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BMW Tech Letters

Nov 11, 2004

E36 with a Virus
I recently had the computer replaced on my 1994 318is. After getting it back from BMW the radio is not working, the heat is not working properly, the window rolls up and down a little bit by itself, and the interior light goes on and off by itself.

I have a little bit of heat coming out of the defrost vents, but have to keep the other vents closed off, because there is nothing but cold air blowing out. The button that changes the air flow from outside to inside will not work. Also, the button for the rear defrost and air conditioner don't work. BMW is saying that it's nothing they did, but it all worked properly before having the computer replaced. I really need some help as to what might have caused this and if it was their fault. PLEASE HELP!
Thank you,
Rachel Carnes

2017 BMW 3-Series
$33,450 Base Model (MSRP) 23/35 MPG Fuel Economy

There's not much we can tell you that you don't already know, Rachel. You have to work this out with the dealership, or else pursue it legally, perhaps through your state consumer protection agency. It is unbelievable that they would deliver the car in this condition. With electronic cars come electronic problems, and this car certainly has some. However, from your description and given the sequence of events, the first thing I would check is battery voltage. When these cars suffer from a low voltage condition it's like an unstable event in Windows 98, but usually there is a drivability complaint as well, like poor running at start up. Also, battery voltage can drop pretty low if a new electronic control unit is programmed in the car without a battery charger being used at the same time. You might need a new battery. If you do, don't buy one from BMW -- BMW replacement batteries are overpriced and wear out quickly. Get an Interstate MTP-91 (, which has a provision for the battery vent tube on this car. Here is my advice: Call the dealership and speak with the service manager, not the service advisor. Be polite. Inform him of the sequence of events and tell him your car was delivered to you in horrible condition with problems it did not have previously, and that you think you have a right to expect that the problems be fixed. Tell him you spoke with a knowledgeable person who suspected the problem might be low battery voltage, and ask him to diagnose that and whatever else needs to be done to make the car right. Discuss with him in advance who will be responsible for what charges.
Best regards,
Mike Miller

5 Goes Into 3?
I have a 1987 3 Series. I was wondering if a 5 Series motor would fit into the 3 Series car?

Sure. With enough time, money, and skill, the versatile E30 chassis will swallow almost any BMW engine including the V8s. I've never seen a V12 in an E30, though. You should know a that the BMW 5 Series cars encompass five generations about ten engine types. So, when you ask if a 5 Series motor will fit in the 1987 3 Series car, that's a pretty broad question. It's relevant because there may or may not be other changes required in terms of the gearbox, driveshaft, and differential depending upon which 5 Series engine we're talking about. Often, suspension and brake upgrades are required, too, due to added weight and power.
Best regards,
Mike Miller

Engine Swaps Complicated, Expensive
I have a 1998 E36 328i coupe with a manual gearbox. I have brought a 2001 E46 M3 motor and box complete with pretty much everything. I have all sensors, computers, drive shafts etc. I will be putting the E46 M3 motor into my 328i. I have spent some time on forums looking for some answers without much luck. It looks as though this is a fairly new thing to do. I found a site called siastuning that had done the conversion and contacted them without reply. From what I gather so far the motor box will bolt in without any major dramas.

I recently sat down with the chaps at my local big BMW dealership and the thought of the conversion terrified them, not from the point of bolting it in but by making the systems talk to each other. They were trying to explain to me that the new E46's use a square wave Vs -- something different from the E36. Whilst I was trying to keep on top of the conversation it was all above me. They told me that when I get it running with the computers from the E46 none of this will communicate with my E36 systems, i.e., It will not talk to my ABS, my instrumentation...nothing.

I have two shops that are prepared to go ahead with the transplant but before I give the go ahead I want to make sure that I have as much covered off as possible. My fear is that the car will spend the next twelve months sitting in the corner of a shop whilst they scratch their heads and make excuses, which has happened to me before.

The standard thing I get told is to forget it and go with the E36 M3 motor. Fair call, however not an option. If I wanted this I would have just brought an M3. In Australia turbo's are frowned upon by insurance companies; this swap does not present me with the same problems.
Kind regards,

You won't have a problem bolting in the engine or the gearbox, but you will probably wind up needing an E36 M3 driveshaft for a six-speed gearbox E36 M3, meaning not U.S.-specification. With the electronics, the answer is...who knows. I've never been involved in such a swap, nor would I be involved willingly. I think you're going to spend a great deal of money making the E36 electronics work with the E46 engine ECU, and I think it will require the skills of a master BMW electronics technician. I further think no one but he will be able to diagnose and repair subsequent electronic malfunctions in this car. By the time you're done writing cheques, for a bit more, you might have the E46 M3 engine with the E46 M3 wrapped around it. The S54 engine block and cylinder head in the E46 M3 are not terribly different from the S52 engine block and cylinder head in the non-U.S.-specification E36 M3. The prime differences are electronic, intake and emission control-related. So, I'm thinking perhaps the expedient way out of this is to use E36 M3 intake, exhaust, and electronics for the S52 engine. However, once again, this will require the skills of that master BMW technician, and one intimately familiar with both cars.
Best regards,
Mike Miller

325iX: One Engine Only
I am gonna get a 1991 325ix. Can I put either the S38, M50 or S50 engine in that chassis with the stock gearbox? Also, what would it take to put lets say an S38 engine into an E30 M3 with the ix gearbox? Can you see what I'm trying to do? An AWD inline six E30.

Thanks for any help.

Sorry to rain on your plans, KB, but the only engine that works in a 325iX is the M20 engine that came with the car. The reason is the front axle, which passes through the oil pan. Now, that's not to say you couldn't somehow engineer and fabricate a custom oil pan for one of the other engines given enough time, money, and access to master fabricators. However, I think it's safe to say the economics involved would be staggering. The 325iX gearbox is unique because of the AWD transfer case, and of the other engines only the M50 and S50 would bolt to a 325ix gearbox. In short, it's not a good plan. On the bright side, if you buy a 325ix you'll already have an AWD inline six E30. Forget about the S38 engine in front of the ix drivetrain --that's just not going to work. Can you transplant a 325ix drivetrain into an E30 M3? I don't see why you couldn't. The question would be, why would you want to? I mean, if you've already got a working 325ix, why transplant everything into another body?
Best regards,
Mike Miller

Differential Difference

I am starting to work on a 1998 BMW 528i automatic which I found with 76,000 km. Not bad. I know this is a European-specification 528i, but I believe that it is a mechanical twin to its U.S.-specification counterpart. Either way, this car will basically be updated to an M Technic 5-series. Only factory mod: BMW 17-inch wheels.

My questions should be simple ones for you. 1. Is the differential in this car the same as a 3 Series of the same year. I am considering swapping the differential to a much more aggressive one. Which do you recommend? My average cruising speed on long runs is about 80 to 100 mph (basically 140 - 160 kmh). 2. Would you recommend removing the catalytic converter? With the rear M5 bumper I will get an aftermarket exhaust, but since we have no EPA control, I have no problems removing the "cat".

3. So what is the word on intakes? Thinking of the Autothority intake, is it worth it, or just get the drop-in one? Any other suggestions? Thanks.
Paul Days
Dominican Republic

1. The first step is to determine what differential ratio is in the car now. BMW plays around a lot with differential ratios on the automatic cars to make them accelerate for the U.S. market. If this is a US-specification car, it "most likely" has a 4.10 differential, however the ETK also shows a 3.46 differential in the slushbox column, with no notations or explanations. The European-specification E39 528i uses a 2.93 differential ratio up to 09/98 production and a 3.07 from 09/98-on, while a 3.46 ratio was optional. BMW production dates are noted on a sticker in the drivers door jamb. But bottom line, you're not going to know what ratio you have to begin with unless you get under the car and look at the differential ratio tag on one of the cover bolts. Hopefully it is still there. Now, which ratio to use depends on what you want the car to do, which was not clear from your e-mail. If you want to improve acceleration, then the ticket is the 4.10 ratio without question. The trade-offs are higher engine speeds at any given road speed, and a reduction in fuel economy. If you want to reduce your engine rpms at your long run cruising speeds, then one of the higher (numerically lower) ratios would be the choice. The trade-off there would be some more acceleration time. The differential part numbers are different, E39 5 Series versus E46 3 Series. This does not mean there is no interchangeability, but I've never tried it so I don't know for sure. Other BMWs, for example the E28 5 Series and the six-cylinder E30 3 Series and M3, can swap differentials if the cover and output flanges are also swapped. However, buying a diff for the car you have certainly removes all doubt. 2. There is no performance benefit to removing the catalytic converter by itself unless it is clogged, and the questions arises, "What would you replace it with?" The restriction in BMW exhaust systems is upstream from the catalytic converter, between it and the engine. So, if you wanted to replace the exhaust manifolds with headers bolted to the catalytic converter, I would say that would likely provide some performance benefit. The only headers I know of for this car are made by Supersprint, which are sold by various BMW shops and tuners in the U.S., many of whom advertise in European Car. 3. Beyond corporate puffery and specifically with respect to BMW engines, I don't see any benefit to the in-the-airbox oiled cotton gauze air filter. My feeling is they may afford an airflow improvement for cars equipped with air filters that are too small. But BMW air filters are huge. I have a hard time believing there are any restriction problems with the filters themselves. Now, the BMW airbox is a different question. I can certainly see restriction there.

With a BMW engine, if you were to go to a cold-air intake setup using a cone-type oiled cotton gauze filter filter, then that, combined with performance software, can yield a power increase. Will you notice it? That depends on the car and the driver. Modern BMWs are pretty well optimized right from the factory. Older models can benefit tremendously from a chip and intake program. And drivers? Some guys can bolt on 30 hp and not notice the difference. Other guys will trade their kids for another five ponies and be able to graph the difference.

Moreover, you need to understand the specialized maintenance required by an oiled cotton gauze filter. The element is oiled cotton gauze, not paper. When the filter is dirty, you or your technician will have to remove the filter, soak it with K&N Air Filter Cleaner (no substitutes), painstakingly wash the element with water (never ever use parts cleaning solvent on a K&N filter), wait for the element to air dry, re-oil the element just so -- not too much, not too little -- using K&N Air Filter Oil (no substitutes), wait for the oil to distribute itself throughout the cotton gauze element, and then reinstall it. This is not as big a deal as it may sound especially if you keep two filters and rotate them into service, but if you aren't going to perform this maintenance work yourself and your technician isn't interested or trustworthy enough to do it, then keep the stock BMW air filter. It works just fine.

There are also sporadic issues of mechanical problems because someone over-oiled an oiled cotton gauze filter element, and engine problems because someone under-oiled the element. We also get varying opinions on the filtration abilities of oiled cotton gauze air filters, with some tuners claiming that the regular stock paper filter does a better job of keeping dirt out of the engine.

4. I can see that you want to increase this car's power, and you should know that there are no dramatic increases to be had with bolt-on parts short of supercharging. And what you do get is going to be muted by the automatic transmission, which tends to keep the engine out of the rpm range where performance parts yield their incremental power increases.
Best regards,
Mike Miller

I have, or should I say had, a 1989 BMW 325is. The timing belt broke while I was starting the engine. The shop estimates repair costs at $2,400. I cant afford that. What should I do?
Devin Flannery

The BMW M20 six-cylinder engine is known as a "crasher engine," meaning that if the timing belt breaks the valves hit the pistons. The best case scenario is bent valves, meaning a complete valve job or salvaged cylinder head. At worst, the valves can destroy the pistons, as well. To prevent failure, BMW timing belts MUST be replaced every 50,000 miles or every five years, whichever comes first. Last timing belt replacement should be noted on a sticker in the engine compartment, in the vehicle service booklet, or both. Devin, I'm sorry to hear of your misfortune, but part of the responsibility of car ownership is to educate ourselves on what maintenance needs to be performed and when on the cars we own. At this point, I suppose you should sell the car as is. Speak with the shop. If the rest of the car is in good condition, one of the technicians may be interested. In fact, some 12 years after the last timing belt-equipped Bimmer rolled out of the factory, many BMW technicians would have nothing to drive were it not for customers who break timing belts. Readers should note that very few BMWs have timing belts; most use a timing chain. Here is a chart:

BMW Engine Timing Belt Applications
The Following BMW Engines have Timing BeltsAll others use timing chains.

M20 Engine, 2.0, 2.3, 2.5 or 2.7 liter six-cylinder SOHC

Applications (including Touring and Cabriolet):

E12 body non-US
520, 520i, 525, 525i

E21 body non-US
320, 320/6, 323i

E30 body non-US
320, 320i, 323i, 325e, 325i, 325iX

E30 body US
325e, 325, 325i (1987-1991 [1992 cabrio]), 325iX

E34 body US
525i up to (not including) 1992 only

M21 Engine, 2.4 liter SOHC diesel, normally aspirated or turbocharged

Applications (including Touring and Cabriolet)

E30 body non-US

E28 body US
524tdM40 Engine, 1.6, 1.8 liter four-cylinder SOHC

Applications (including Touring and Cabriolet)

E12 body non-US
518, 518i

E21 body non-US
316, 318, 318i

E30 body non-US
316, some 318 and 318i

E36 body non-US
316i, some 318i (including compact), 316p (propane fuel)

E46 body non-US
M41 1.6 liter SOHC diesel, turbocharged
E36 body non-US
316td (compact)

Test Driving is Good
I recently bought a 2002 BMW 325iT for my wife. The car has everything she wanted--premium package, the right colors, heated seats, and a wagon to boot. She loves the 17-inch wheels that came with the sport package but finds the lowered and stiffened shocks and springs to be a bit rough for daily driving. I own a 528i and agree that her car rides pretty roughly on uneven pavement, which we have a lot of in our area. I'm looking for a good set of "comfort shocks" for her car. I don't mind giving up some handling and even raising the stance of the car is not a problem. Since most aftermarket suspensions are designed to be more aggressive than stock and even manufacturer sport suspensions, I am having a problem finding one focused more on comfort.
Charles Guilliams
via the Internet

Charles, your letter illustrates why it is so important to test drive cars before buying. I can't begin to tell you how many letters I answer from readers who bought the sport package but don't want it, or didn't buy it but desperately want it. The two most common complaints I receive about BMW suspensions are, "It rides too firmly" and "It doesn't ride firmly enough." Someone ought to create a Web site where you guys can all swap shocks and springs.

You can't find shocks and springs focused on comfort because those are the ones already on your car. Aftermarket shocks are either performance oriented or original equipment equivalent, and aftermarket coil springs are all performance oriented. The factory parts are the soft-riding parts.

Unfortunately, if you want to keep this car and soften the ride, your only choice is buying non-sport package shocks and springs and installing them in your car. This is going to cost a great deal of money at the dealership. The car will then need a four-wheel alignment to non-sport package specifications. Make sure the technician loosens the rear trailing arm bushings before the spring installation, and then torques them to spec with the car in its new operating position--otherwise they'll be pre-loaded and will fail quickly.

Speaking of Web sites, you might try posting on the E46 board at I have no doubt you'll find someone who will want to trade you his standard 325iT shocks and springs for your sport package parts. Try to stay away from shocks with many miles on them--try to keep it under 30,000. Otherwise just buy new shocks and trade springs.

Choosing an independent BMW shop
I have a 1988 BMW 325iX and I'm looking for an experienced independent BMW technician. I live in Patchogue, New York (Suffolk County, Long Island). Any shops pop up on your radar? Competition BMW of Smithtown is the closest dealer to me but at $110 per hour for a 16-year-old car I can't stand to pay it.

Also, it is coming time to sell or restore the car. I would really like to restore and upgrade it. Do you know any BMW specialists in the area, or is Korman the only option? Thanks for all you help in advance.
George Garcia
Patchogue, NY

Initially, Korman Autoworks is a fine shop but they're in North Carolina--a bit far afield from Long Island, eh? Word of mouth is the best way to find an independent BMW shop, generally speaking. The question then becomes where to hear those words of experience. Members of the BMW Car Club of America ( have two unique resources at their disposal in this regard. First, you can attend local chapter meetings or call the local chapter technical representative and get in-person advice regarding your fellow members' experience with local shops. Second, you'll receive a regular chapter newsletter in which local shops typically advertise. In my experience, if a shop cares enough to advertise in the local club newsletter, that speaks well of them caring enough to correctly maintain and repair your Bimmer as well.

Another resource anyone can use is, which is the Web site of the International Association of Independent BMW Service Professionals. Membership in this organization gives technicians and shops a "leg up" on BMWs propensity to keep any and all vehicle information secret, because members share information and have access to a communications network among fellow members. Members also purchase access to BMW's Technical Information System and GT-1 computer--significant investments in their businesses. One member shop is located in New York, Bay Diagnostics in Brooklyn.

Of course, non-membership is IAIBMWSP does not mean a shop is somehow deficient--that's not the case at all. I know of two shops in your general area I can recommend personally: Little Garage ( in Huntington, NY, and Performance Service Parts & Auto Body in Dobbs Ferrry, NY (914-963-9830).

Now let's talk about pricing. If I'm a BMW technician and I charge $110 per hour or some similar high amount, there are usually two reasons for it: 1) The geographic location of my shop is such that the market will bear the price--in other words, my customers tend to be well off; and 2) The geographic location of my shop is such that my overhead is very high--in other words, I have to contend with Big Government. Guess what? Long Island has both going for it. Moreover, and this is nothing against any particular shop in your area or anywhere else, the rip-off phenomenon--i.e. money paid, work not done-- is far greater in large urban areas than it is in rural areas or the heartland of America. This is why the independent shop I worked at in Vermont has a customer base about 40% from New York City, Boston, and urban New Jersey.

Traditionally, labor charges only cover a shop's overhead, the costs of doing business. Because these costs are higher in urban areas, labor charges are higher there, as well. Traditionally, parts profit--buying parts and selling them at or slightly below BMW of North America suggested list price --were the shop's only profit. Well, that was then and this is now; parts are no longer as profitable as they once were. So labor charges have, in some places, been bumped up to make the business float. And labor charges go up each time those costs of doing business increase. For example: expenses occasioned by environmental regulation, insurance gouging, state inspection mandates, diagnostic equipment, facilities expenses, real estate taxes, income taxes, the local anti-car Hysterical Society, the zoning board, and the dog lady across the street who calls the police every time you start a car with a broken exhaust before 7 a.m., even though she's up at 4 a.m. to let her dog deposit little presents in front of your shop. It ain't easy having a shop in an urban area, George.So, the further you are willing to travel from your home for BMW service, chances are good the less you will pay, and it is possible you'll receive better work as well.

Heater Troubles
I have a 1988 BMW 325i but no owners manual. I am trying to get my heater to function, and I don't know where to start. I was thinking to check the relays but I don't know which relay goes to what. There is an orange relay under the steering column and there are eight under the hood. Six of them are orange and 2 are silver; the numbers on the case for them are K1 through K8. I need to know the accessories that these power.
Nick Cottingham
via the Internet

You should find an owners manual, but it's not going to help you here. You need the Bentley E30 3 Series Service Manual (, which contains relay and fuse keys as well as blower motor diagnostics. The procedure and circuitry are too elaborate to retype here, and besides you'll need the diagram.

That said, none of the relays in the fusebox control the blower motor. Fuse number 20 (30-amp) sends power. At high fan speed, full power is supplied to the blower motor. At lower fan speeds, a series resistor assembly controls power to the blower motor, reducing voltage in three stages accordingly. This series resistor assembly is integral to the blower motor, and cannot be replaced separately.

The Right Parts for the Car
I own a 1995 BMW 325is. I just got a set of Hamann wheels that came off a 5 Series (low offset). They are 18-in. and stick out in the rear too much, rubbing against the fender. My question is would it work if I replaced my rotors and calipers with M3 parts?
Julian Santos
via the Internet

Julian, the problem is not the rotors and calipers; the problem is you bought the wrong wheels for the car. You haven't told us the offset of these wheels, but we can't take away what is already there. Spacers aren't going to work. Moreover, if these wheels came from an E39 5 Series BMW, then the hub diameter is also wrong. They will not fit hub-centrically on an E36 3 Series, meaning the car is going to vibrate like a Catholic schoolgirl's nightstand. I suspect you have E39 5 Series wheels, because no other 5 Series except the current E60 had 18-inch Hamann wheel fitments. Sorry to bear bad news, but they will never work on this car.

Used 7 Series: BMW Technicians' Work Car of Choice
I am looking at purchasing a 1988 BMW 750iL with what has been described as a malfunctioning computer for the transmission. The current owner states that the vehicle was in "safe-mode," which only enables reverse and the high gear to function. The transmission has already been replaced, so the mechanical variable is out of the equation. I'm curious if what's stated is factual. Can the computer be reprogrammed or can this "safe-mode" be deactivated? I thought it a wise course to ask before making the purchase to prevent wasted money and the frustration it creates.
Shannon Posey
via the Internet

I wouldn't write off the transmission quite so fast, Shannon. The 750iL is an extremely complex car with a classic example of BMW's persnickety automatic transmissions. You need to have this car checked over thoroughly by a professional BMW technician, dealer or independent, at your own expense, in order to have any idea what needs to be done to sort it out and to make an informed purchase.

If things are as the current owner says, then you need to buy a new EGS control unit for the transmission, from BMW, at great expense.

These issues and many others illustrate why the out-of-warranty BMW 7 Series V8 and V12 models make wonderful 150-mph work cars for BMW technicians--they're the only ones who can keep up with the electronic foibles, cobbling together e-boxes from the core pile in the corners of their shops. I know techs who buy these cars for very little money from customers who are at the end of their rope.

Automatics Suck
When my 1989 525i automatic is running reverse gear acts like park and neutral actually works as a drive gear, but when the car is off neutral goes back to normal--in other words, I can push the car and it will roll. I disconnected the shift linkage and reset it but it did not perform any differently. Also, the car will start in any gear and I know it's not supposed to do that. Since it only acts up when it's running, I started thinking that maybe it was a computer problem. Is my problem something major requiring a shop, or might this be a problem I could take care of myself if I were mechanicaly inclined?
Bert Aguayo
Dallas, TX

Your problem does seem link it is linkage relate--or at least hardware related rather than electronic. I'm a bit perplexed by your statement that it only acts up when it's running--when else would an automatic transmission act up? Without having the car here there's not much help I can render, but this problem requires hands-on work. I recommend you take the car to a professional BMW shop, dealer or independent.

On the bright side, if you can get the shifter into a position where the slushbox shifts normally it is unlikely that you need a new transmission, which is normally the diagnosis when a BMW automatic acts up.

Anything fits in any E30...well, almost
I have a 1991 318is with a thrown valve stem. I've been reading through some of your technical questions and answers, and I was wondering about all the possible engine swaps I could perform and all the parts I'll need. Also, what are some good Web sites I where might find these parts?
William Saylors
Bowie, MD

Initially, I'm curious about what happened to the original M42 engine. You say it has, "a thrown valve stem." That doesn't tell us much. What exactly happened--did a valve spring or valve spring retainer break?

The E30 3 Series will accept just about any BMW engine you want to install. I've never seen one with a V12, but I have seen a few V8s and every four and six cylinder engine BMW makes. It all depends on how much money you want to spend, as an engine swap can easily exceed the cost of a replacement BMW with the engine you want already installed. Obviously, the least expensive route is to install another M42 engine. You should know that E36 3 Series M42 engines are different from yours. You can use an E36 M42, but you'll need the engine wiring harness and the DME computer, and possibly the ancillaries.

As for six-cylinder engines that will bolt to the existing manual gearbox, that narrows you down to the BMW M50/S50 engine family produced from 1992 through 1995 for OBD-I. Other mods will still be required, though, such as E30 325i front springs and strut inserts to handle the extra weight. You'd also need a new radiator and exhaust system, a cobbled combo of E36 front exhaust parts and E30 325i rear exhaust parts. You'd need to modify the rear valance panel to clear the dual tail pipes. If this swap interests you, visit They sell an instructional CD that walks you through the conversion, and they sell parts kits for it, too.For used parts in general, visit and

Hard Start Problems
I have a 1994 325is five-speed. The check engine light is on. It suffers hard starting and sometimes dies at idle, but will restart again. After it warms up there no problems. I went to dealer and he said it was the low speed idle control valve. I replaced the valve but the car still has the same problem.

Next problem: If I leave the car sit turned off for 10 minutes it will not restart. I have to wait at least 45-60 minutes to restart the car. I have the shop manual, and am looking for professional direction.
via the Internet

First, you need to download the onboard diagnostic codes to see what's setting the check engine light, then proceed diagnostically from there. If you have the Bentley E36 3 Series Service Manual, it will tell you how to get the codes and read them. There is also a cold start/run diagnostic trouble tree, which you should then follow. There are many things that can cause this problem.The second problem sounds like it may be completely separate, but also requires hands-on diagnosis. While the car will not start, you need to determine if there is power into and out of the main relay and the fuel pump relay. If there is no power at the main relay, then you're looking at either an anti-theft system problem or the ECU. If there is power into but not out of the main relay, then it's the relay. If there is power into and out of the main relay and into the fuel pump relay but not out of it, then you need a fuel pump relay. If there is power all around but no fuel pump function, then you need a fuel pump. There could also be wiring issues, or an ignition problem. On a BMW six cylinder of this vintage I would also not discount ignition coil problems, but I don't think that is the cause of these problems.

Raising the Bar
I want to raise the level of perfromance in my Bimmer. It is in good condition, a 1994 318i. Could I swap my four-cylinder engine for an M3 engine? What kind of engine would I need? I don't how do I go about upgrading my old engine.
via the Internet

I would say if you're daunted by upgrading your existing engine, then an engine swap is going to be well outside the realm of your mechanical ability. If you're paying a professional, then I can promise you it will be less expensive to simply sell the 318i and buy a used E36 M3.A performance chip and exhaust system can free up some power on the M42 318i engine, but the difference is not dramatic. The dramatic difference comes from a Downing/Atlanta Supercharger (, which can produce about 215 hp. It makes the 318i feel like a warmed-over 325i. The bolt-on kit is very nice, and affords you hot-rodded 325i performance at 318i insurance rates.

The engine swap would require a 1995 OBD-I M3 engine or a modified 1996-1999 OBD-II M3 engine. You can use your existing manual gearbox and differential, but you would need to upgrade the suspension and brakes to M3 components at a minimum.

Brake and suspesion upgrades would be very smart on a supercharged 318i as well, however M3 suspension parts would only be viable on a six-cylinder engine conversion due to the increased weight involved. For a supercharged 318i, use aftermarket 318i parts, such as Bilstein Sport shocks and shorter, firmer aftermarket coil springs. I would also recommend E36 M3 front control arm bushings and E46 M3 rear control arm bushings. When installing rear control arm bushings in an E36 or E46, it is critical to torque the control arms to spec with the rear supension in normal operating position, not full droop. Naturally, a four-wheel alignment will be required after the work.

BMW Coil Spring Interchange
I have a 1997 BMW M3 and intend to install lowering springs from Dinan and Bilstein shocks. My son owns a 1994 BMW 318i. Can the original suspension components from the 1997 M3 be installed on the 1994 318i? Does this require a different wheel and tire combination? Are there any other issues to consider?
Fred Striz
via the Internet

The 1997 M3 coil springs and shocks will physically fit a 1994 318i, but they will be wrong and perform poorly due to the fact that they were designed for a car that's heavier in the front. If your son had a six-cylinder E36 3 Series car, it would be no problem. But the four is lighter. These parts are blind to wheel and tire combination--if it fits with the original parts, it will fit with the M3 parts. I would be less concerned about fitting the shocks than the springs, as vehicle ride height is entirely a function of the springs. However, there's no doubt that the front shock damping would be pretty firm for a 318i. Never having done this, I'm not sure what effect that would have on drivability.

Coil springs last for hundreds of thousands of miles. One issue to consider with respect to the shocks is, are they now worn to the point where installing them on another car is pointless? If they have much more than 50,000 miles on them, I'd say forget it.

The Right Parts for the Job
I just bought a 1977 633CSi that needs body work. The front fenders are too badly deteriorated to be restored, and I need replacements. I'm wondering whether the E23 7 Series fenders have the same size and dimension as E24 fenders. Are they replaceable?
Karin Tanphiphat
via the Internet

E23 7 Series fenders will not work. E24 6 Series fenders are unique, although the car itself shares certain mechanical parts with the E28 5 Series. Replacement fenders are available through BMW. To my knowledge, no aftermarket replacement E24 fenders exist.

Square Lamps
I read in an article on the Bermuda show in SCC magazine stating that one enthusiast contacted you regarding the BMW E30 square headlamp kit fitted to one of your feature cars. I would like to know where to find one as well. I've searched the Internet to no avail. Can you help?
R.R. Jacobs
via the Internet

The only vender we know that carried this kit was Racing Dynamics. Catalogs from the late 1980s show it. Personally, I recall that it didn't seem to be very popular at the time. The parts included custom grilles and headlight bucket assemblies. Four 4x6-in. rectangular headlamps were used.In any event, this kit is no longer made. I would say the best place to look for used kits would be Ebay and

E36 Camshaft Timing: Not a Simple Matter
I live in Costa Rica and I own a 1993 BMW 325i (with VANOS). The previous owner installed a pair of stock 1995 M3 camshafts in the car, but since he lacked the proper specs, the camshafts were tuned as stock 325i by the local BMW dealer. I know these camshafts can provide my car at least 20 hp more that would be very useful around the track. I have been searching the Web, and sending e-mails to several BMW Web sites, without any luck, for over a year now. That's until I noticed that Pablo Mazlumian reinstalled stock camshafts on Project M3.By any chance can you provide me the tuning Specs for the E36 M3 stock camshafts? I know several good mechanics here that can tune them up if provided with the right specs.
Juan Rodriguez
via the Internet

The actual procedure for adjusting cam timing on this engine is quite complex and several special factory tools are required. The procedure requires diagrams, so I can't retype it here.

E36 Problems Transcend International Boundaries
I wonder if you can give me suggestions for solving two problems with my BMW E36 1996 318i SE auto. It has just 55,000 miles and a full service history.

1. In the first half minute or so after starting it is only firing on three cylinders. It then tries all four a few times, then sorts itself out and runs normally, (except for the next problem which I'll mention shortly). It has recently had new plugs, so I am inclined to suspect that the gaps aren't correctly set, but are there any other obvious things I'm missing?

2. Driving at a steady speed of about 50 to 70 mph, with a steady throttle, the fuel consumption meter fluctuates up and down, not a lot, varying by about 3 to 5 mpg. It doesn't seem to happen if the consumption figure goes high, on a down slope, or low on a hill. I can't be sure but I think there is a slight, barely perceptible surging, in time with the movement of the meter. I am not concerned with the consumption as such, rather if it is indicating a problem somewhere else.
David Marsden
Watford, UK

These problems do require hands-on diagnosis, but we'll give it shot:

1. Initially, there is more to a tune-up than new spark plugs. If this car is running its original air and fuel filters, replace them now and test drive the car. If the problems are still present, I suggest having the ignition coils "scoped" for secondary resistance testing. This will require a trip to the BMW dealership or a well-equipped independent BMW shop. Ignition coil failure is not uncommon on these engines. If you have a bad one, replace all four.Spark plug gaps are factory-set for this engine; there is no need to set the gap if you are using the correct NGK or Bosch copper spark plugs.

2. This problem could be related to the first if, in fact, there is an ignition miss. If this problem persists after fixing the first, then remove the idle control valve and clean it out using spray solvent and test drive the car. If the problem is still there, diagnose the idle control valve using a digital voltmeter and the specifications in the Bentley E36 3 Series Service Manual.

E36 M3 Bilstein Part Numbers
I have 1997 BMW M3. I bought Bilstein shocks and don't know if I have the right part numbers. Maybe you can tell me if this is right and if not what the correct numbers should be. I have: f4-be5-2453-ho.
via the Internet

We spoke with Doug Mahar at Turner Motorsport ( regarding your question. Here are the Bilstein shock part numbers for a 1997 M3:

VE3-A585-H0 Left front
VE3-A586-H0 Right front
BE5-2453 Rear

Looks like you have the rear part number, sort of.

Running Cars Worth More
I have a 1985 two-door BMW 325es with an excellent engine, and also a 1990 325i four-door with a worn out engine. Each has a five-speed manual gearbox. What is involved in an engine exchange from the 1985 325es to the 1990 325i? I have started to remove the 1990 325i engine but I have not yet done the wiring harness because I was told to get more information before proceeding.
Lonnie Smith
via the Internet

Well, the 325es is a pretty cool car. It has Recaro seats, Bilstein shocks, and excellent aerodynamics right from the factory. The low-revving eta engine doesn't have a BMW personality--at least not from that era--but it does make great low-end torque. By contrast, the 1990 325i four-door has a nice rev-happy engine, but, well, it's a four-door.Does the 1990 325i run, at least? A running car is worth a great deal more than a non-running car, even if it requires engine work or an overhaul. Why not sell the 1990 325i and dump the money into the 1985 325es?

However, if you're set on the engine swap, you will need the engine wiring harness, the electronic control unit, the instrument cluster (for the tachometer), and the differential. The 325es differential is probably a 2.93 (it could be a 2.79 depending upon production date), which is good for the eta engine. The 1990 325i has a 3.73, which is better suited to the higher revving engine and essentially unusable with the eta engine. You will also need to swap the complete exhaust system. The gearbox and driveshaft do not have to be swapped.

ETA to "i" Conversion?
I purchased a 1985 E30 with a 2.7-liter engine supposedly built by MK Motosports in Germany. The MK Motorports logo on the speedometer and gold painted rocker arm cover look original. I contacted MK Motorsports who have no record of the VIN and cannot tell me what went into the engine. They suggested I ship the engine from Canada to Germany and they could rebuild it, but that's too expensive.

I suspect that the conversion uses the BMW diesel forged crank, with possibly changed rods and pistons. The original cam was changed and replaced with a Bavarian Autosport European 323i cam O.E.M. BMW part. The engine pulls from as low as 1,200 rpm and strongly from about 3,000 rpm. It hits the wall at about 4,200 rpm and will continue to rev up to about 5,800 or 6,000 rpm, but there is really no point to it. I'm not sure what the differential ratio is. A dyno test at the rear wheels produced maximum torque of 138 lb-ft at 4,000 rpm and max horsepower of 119 hp.The goal of the project was to build a really nice handling and sweet sounding road car, to use on occasional rallies and the odd autocross event.

I like the torque but would hope for a lot more power from 6,500 to 7,000 rpm. I have the old cam I understand can be reground to mimic the original profile. The exhaust manifold is cracked so a better replacement can be considered. The whole exhaust system needs replacing since the catalytic converter is optional as 20-year-old cars do not have to meet emission limits in Canada. I wouldn't want to do any major machining of the cylinder head other than ensuring that the valve seals and guides and seals are good and injectors are working properly. Given the absence of what originally went into the engine, do you have any suggestions on how to obtain what I want from a 2.7 M20 engine, or should I forget about this as a non-viable project and start with a later model 325i or an M50 transplant. Am I dreaming?
Alan Morris
via the Internet

From your description of the performance of this engine, what you've got there is an M20 eta engine. Whether it was smiled upon by MK Motorsports or someone just bolted on a few of their appearance parts, I cannot say without disassembling the engine for inspection. Building an eta into an "i" engine is pure folly. If you want an "i" engine, remove the eta and install an "i" engine. You'll also need the engine wiring harness and ECU, the tachometer to show the higher rpm scale of the "i" engine, and, if you want to do it right, a lower (numerically higher) differential.

Your current differential ratio is probably either a 2.79 or a 2.93, both eta ratios. The "i" engine was combined with a 3.73 ratio. The hot setup for an "i" engine is a 4.10 limited-slip differential from an E30 M3. Naturally, a 4.10 is totally unsuitable for an eta engine due to its low-revving, low-end torque personality.Have you autocrossed this car yet? Before tearing into the engine compartment, try autocrossing with the eta. You might like that low-end torque.

Lightweight Flywheel HP Gains
Is there a horsepower gain with a lighter flywheel? If so, would it only be at the crank or actually transfer to the wheels? I like the concept of a higher revving engine with a lighter flywheel. Do you as well recommend a lighter crank pulley to release more lost horsepower?Please let me know, as I am looking to purchase one or both of these items. According to the data provided on the Web by different manufacturers, it is an average gain of 2.7 hp per pound shed by these components. Would this equal out to a gain of 33 hp by combining these two components together? Am I being overly optimistic? Should I just purchase a bigger turbo?
Michael Czok
via the Internet

Reducing an engine's reciprocating mass will facilitate faster revving, but not necessarily higher rpm. There is a slight horsepower gain because reciprocating mass causes parasitic power loss--the energy it takes for the engine to spin its own parts. I'm not sure where they got the 2.7 hp per pound figure, and I think the only way you'd know for sure would be to dyno the engine before and after flywheel installation. Yes, you'd have an increase at the wheels, but faster revving would be the chief benefit. I think 33 hp would be a bit optimistic. Also, lightweight flywheels don't always mesh well with forced induction. You want to let the blower work for you, and making the engine spin quicker can work against that to a degree. I'm not saying don't do it, but I'd stay away from the very light aluminum flywheels. If you want to get rid of a dual mass flywheel, which is truly a boat anchor, and replace it with an earlier steel version, I think that would be fine even with a turbocharger. However, I'd also recommend that you run this past the turbocharger manufacturer and get a second opinion. In particular, the manufacturer's engine management software may count on a certain amount of flywheel weight, depending upon the model BMW we're talking about here.

Mass is mass and if it spins it can be lightened, so a lighter crankshaft pulley would have the same effect, only to a lesser degree than the flywheel. Be careful about the construction of the pulley, though. Lightweight alloy pulleys may be fine for limited race duty but not necessarily sturdy enough for forget-about-it street use.

M20 Turbos Available Again
First, great work for the inspiration and knowledge you guys give that has helped with my project a 1991 BMW 325i. I have seen many editors and techs say that there is no forced induction available for the BMW M20 engine. I would like to inform you guys that the Mossleman turbo system for $4,850 does exactly that. Check out Ireland Engineering. It goes from 170 hp stock to the 240 hp after the kit is installed.

I would like to know if there is a past or future issue where you explain how to swap a 1998 BMW M3 (S52 engine) into an E30? Also, do you have any recommendations for tuners in Colorado (preferably in Denver)?Graham Lee Shepard
via the Internet

Mossleman turbos have always been available for the M20, but the question was always, "where?" It has always been difficult to find an outlet for these systems, and your letter may explain why: You can bolt an S50/S52 engine into the car and get that same 240 hp, probably for the same amount of money, and without the complications of turbocharging.

For a while Mossleman turbos were simply not sold in the United States. We're glad Ireland Engineering stepped up the plate on this, as they often do.We've never done a story on the S50/S52 into E30 transplant, but Zionsville Autosport ( has an instruction CD for precisely this project.

Indentifcation, Please?
I have a 1998 323is with 30,000 miles on it. I've had a small leaking of the transmission fluid, which I've fixed and now want to top off the transmission. The caution tag specifies a OEM Dexron III number 83 22 9 407 858 or 859. Since it is Dexron III, can I top off the transmission with an off-the-shelf name brand? And if so, what is the best match for this particular transmission?
C. Yanni
via the Internet

Initially, we cannot tell from your letter whether this car has a manual gearbox or an automatic transmission. If it has a manual gearbox, I would recommend draining the ATF and filling the unit with Red Line D4 ATF (a synthetic Dexron III product,, or Red Line MTL, if you are OK with babying the shifter until the gearbox warms up in cold weather. I recommend changing manual gearbox and differential lubricants every 30,000 miles, the later using Red Line 75W-90 synthetic gear oil.However, you can top up the gearbox using any Dexron III ATF.

If it is an automatic transmission, then it has to be topped off at the dealership. It is filled with BMW's so-called lifetime fill ATF, and there are very specific top-off procedures. The procedures are set forth in the Bentley E36 3 Series Service Manual if you can get your hands on the BMW ATF.

Sudden RPM Jump
I have a 1988 BMW 735i. When I drive at 65 mph and over 70 miles the rpm jump to over 3,500. This is a new condition; before the rpm stayed under 3,000 revolutions at these speeds. We checked my transmission, fuel pressure regulator, fuel filter and cleaned my distributor. Everything seems OK. What is the reason for this sudden jump in rpm above the normal reading?
via the Internet

This 735i has an automatic transmission, correct? If so it is a ZF 4HP22EH four-speed overdrive transmission. To the left of the shifter on the center console, you will see a switch with an "A" and an "M". "A" is for automatic mode; "M" is for manual mode. In manual mode the transmission will still shift automatically if the shifter is placed in "D", but the shift points are at higher rpm and fourth gear is locked out.

I suspect you have inadvertently moved the switch to "M", locking out fourth gear, so that your highest gear is now third, which is a 1:1 ratio. Check the switch.If the transmission is in fact in automatic mode, then I suspect you are still in third gear at the speeds you noted, except it is the result of an internal transmission malfunction.

Popping Out of First and Second Gear
I own an E36 325i 1995. One day, the gearbox began to pop out of first gear without apparent reason. The problem began to get worse with time. Today, it occurs nearly 70-80% of time. I discovered the problem was exposed in BMW's Service Information Bulletin 23 02 99. I live in Ecuador, and the local BMW dealer did not want to take the repair. We contacted Getrag in Germany, the gearbox manufacturer. The cause of that problem, they say, is a faulty first and second gear guide sleeve. An updated part was available, which we requested. We installed the new parts in the gearbox, but the problem remains.The local BMW dealer insists the only solution is to replace the gearbox at a price near $4,000. I have read a lot on the Internet, and this problem appears to be very frequent on BMW's Getrags (316/18, 325).
Eng. Diego Picon
Quito, Ecuador

There was a problem with the guide sleeve on first and second gear in the Getrag 250, as detailed by the Service Information Bulletin you reference. The factory solution was to replace the gearbox with an original BMW rebuilt unit, and if the problem occured under warranty the replacement would normally be done free of charge. Post warranty, replacement is still the dealer solution; BMW dealerships no longer open drivetrain components for repair--their new policy is to replace instead.Now an updated guide sleeve is available, and that's apparently what you installed.

BMW's replacement advice is not entirely unfounded. We spoke with BMW gearbox expert Jim Blanton of regarding your problem. Blanton has been rebuilding BMW gearboxes for about 30 years, so he knows what he's talking about. He says there are other causes besides the guide sleeve defect for this gearbox to pop out of first and second gear:

"I have seen a change in the synchro mechanism from early to late. The vast majority of the time, popping out of gear has to do with shift fork wear, which I have seen and heard about, especially for the first and second gear fork in this model (Getrag 220/250). Assuming that a new shift fork is not part of this kit, then if the wear surface thickness is not 4.4 to 4.5mm, it should be replaced. Of course, if the fork is worn then the question is `why did it wear?' So replacing the fork might only be a short-term solution. It's never simple."

No crystal ball...
I need help. I did motor swap in our 1986 325 and now it barely runs. Is there a site out there to post this and get ideas to make it run? I have a manual and just started checking around, but I'm getting nowhere.Randy
via the Internet

You haven't given us much information to work with here, Randy. Your 1986 325 had an eta engine. Did you install another eta, an "i" engine, or some other engine? What other parts did you replace? Is your ECU compatible with the engine you installed, or did you swap that, too? Have you verified fuel delivery, spark, and electronics on the replacement engine per the manual? We're pretty good, but we don't have a crystal ball.As for Web sites, try

325iX: See Your Dealership
I have a 1988 325ix and I think it's better in snow than the new XI's. Unfortunately, I need to replace/rebuild my transfer case. The chain slips when I shift hard at 5,000 to 6,000 rpm. Also, I now can spin my rear tires without the fronts engaging. Does that mean the viscous coupling is toast?

What are my options? Is there a company that reengineered it to perform better--faster lock? Is a factory BMW remanufactured unit my only option? Can I get a pump and cooler for it? If I have it rebuilt, is there anything I can change to it to improve it? Can I have the viscous coupling pressurized more to increase lock-up like they do on the remanufactured Mitsubishi Eclipse unit?My rear differential has a viscous coupling also. Is this better than a LS differential or an ATB Quaife differential? My front differential is open, can that be changed to a LS or ATB?

Also, can you tell me where I can get E30 M3 fenders and rear quarters? I did some searches and came up with nothing. I remember years ago a company in New Rochelle, NY made fiberglass ones. I think they were featured in your magazine. Not sure what year or month, I'm talking about 7-10 years ago.

Is there a company that makes equal-length shorty headers for my car? I know the full headers from SuperSprint and Stahl wont fit. I found MSDS shorty headers but they are not equal length. The shorty headers from Ireland Engineering say it's close to 1:1 but the primaries are not mandrel bent tubes. Some of the primaries are tubes welded together and have some sections of the pieces welded protruding into the ID of the tube (reducing ID and flow characteristics) and the ports in the flange are out of round (1/4-in. off) so it would most likely leak, I think. How important is it for the primaries to be equal lengths? Is a custom set the only way to go? Will a set of shorty headers for a M50 engine work on a M20 engine if you change the flange? They look like they line up.
George Garcia
via the Internet

George, I hate to torpedo your battleship, but you're not going to be able to do anything you want to do-- at least not without spending many thousands of dollars to pay a professional race engineering team to perform the necessary research, development, and prototype testing. So, unless you're building Team 325iX with financial backing from Halliburton, it's time now for you to develop a relationship with your local BMW dealership.

There is no need, nor is there any precedent for, modifying 325iX drivetrain components. The car was built as an alpine region snow car, not a track car. As you have discovered, it works quite well in snow--that's its forte. I don't know any technician in the United States who rebuilds 325iX drivetrain components, but you might want to check with My feeling is you're going to wind up buying a factory BMW remanufactured transfer case. Maintenance-wise, transfer cases usually fail for lack of oil changes. They also tend to leak. I recommend Red Line D4 ATF in the transfer case, Red Line 75W-90 synthetic gear oil in the differentials and the transfer case, and Red Line MTL in the manual gearbox. Change it every 30,000 miles.

Forget about M3 fenders and quarter panels. Keep the ones you have. Same with headers, unless you can pay a race shop to create a custom set for you. That would require a great deal of dyno testing to get it right, or close to right. You could have the stock exhaust manifolds honed, though.The 325iX is a great car right out of the box, but you have to recognize the purpose for which it was built and work within that mission or you will be out a great deal of money. For engine power increases, anything you do past a computer chip is going to require a rebuild using high compression pistons, a sport camshaft, cylinder head porting, and exhuast manifold honing.

Mystery Chassis
I just bought a 1991 BMW 318i and need to repair the power steering rack and pinion unit, but I don't know which body style the car is. The parts list I'm looking at lists both the E36 and E30 models for the 1991 model year. How do I tell the difference?
Aaron Partlow
via the Internet

You didn't tell us your location or the country specification of this Bimmer, but if it is a U.S.-specification car then it is an E30 3 Series. The E30 3 Series was imported to the United States from the 1984 to 1992 model years, convertibles only in 1992. The E36 3 Series coupes and sedans began to show up in the United States for the 1992 model year.

325i Sport
My dad recently purchased a 2003 BMW 325i with no options but the sport package and sunroof. I was wondering if there are any bolt-ons worth buying that will give the 184 hp engine a nice little boost.
via the Internet

Sounds like your dad and I think alike, although I probably would have nixed the sport package (it's only seats, wheels, and tires, which I'd be replacing anyway) and the sunroof in favor of xenon headlights.Forced induction is the only way to get major power gains out of this engine. Your one-stop shop for the 2.5-liter mill is

Why Swap?
I am an Aussie and I have a 1985 323i, which is very stock standard. I have very little knowledge of the engine. I want to work it a little bit, and it was suggested that I put a 325e engine in it. Would this have many advantages? What degree of difficulty and cost is involved?
Nathan Bush
via the Internet

Sure, you can install a 325e engine. Why would you want to? I am not sure of the power specifications for the Australian E30 323i, but I think it's safe to say the 325e engine will have less horsepower. Its low-revving nature (redline of about 5,000 rpm) will be incompatible with your differential ratio, which I would think is a 3.73 or 3.91. You'd be better off working with the engine you have, or if the car needs a new engine, a 325i engine. If you do go with a 325i engine, you will need the engine wiring harness and electronic control unit.

M20 Turbocharging: Mossleman's the Name, Blowers are the Game
I'm the proud owner of a 1987 325is. I'd like to turbocharge it, but I am kind of at a loss for what to do. I'm not sure anyone makes a turbo kit for the M20 engine. This is going to be a long time project car, so any suggestions would be appreciated, like should I do the M50 engine conversion like BMP Design, etc. I was also wondering if I could change my four-lug hubs to five-lug.
Paco Rockenmacher
via the Internet

Your turbo kit is available from Mossleman. Visit Whether to turbocharge the M20 or install a later twin cam engine, for me, depends on the condition of the M20. If it's in good shape, then why not work with what you already have? If it needs a rebuild, well, then the question becomes can you find a twin cam motor (M50/M52, S50/S52), and how much will it cost? If you go this way, visit for their instruction CD on the conversion. In the end, either route is going to cost a great deal of money--probably about the same amount.

Sure, you can convert to five lugs. All you need to do is convert the car to E30 M3 front strut housings and rear trailing arms. You'll also need to do an E30 M3 full brake conversion including the master cylinder, and install an E30 M3 front sway bar (actually, you wouldn't have to do the bar, but it would be cool). Sounds simple; costs a lot. The thing is, there's really not much benefit in a five-lug conversion. There are E30s out there with 300 hp running four-lug hubs.

Let BMW Build It!
I have a 1993 325is. I will soon do a manual conversion because I'm tired of the four-speed automatic. Before I do that I want to know if I should do an engine swap for an M3. This swap will probably run me $3,000 to $4,000 for the engine alone. What is the big difference between the two engines? I know the 50 hp is what separates them. But could I do some internal engine mods or use an M3 engine management computer to reach that extra 50 hp, without having to install an aftermarket intake and such?
South Bend, IN

Let's say your Bimmer is can be sold as-is for $5,000. You want to take this $5,000 automatic transmission Bimmer and convert it to a manual gearbox, which is certainly a noble undertaking. For the sake of argument, say those parts are going to cost you $2,000. Now, you're also thinking about an M3 engine. We'll split the difference at $3,500. You now have $10,500-worth of Bimmer sitting in your garage, and you have not yet upgraded the suspension or the brakes to handle the added power. Let's say you get away cheap and spend $2,000 on these upgrades. You're now up to $12,500 and you still don't have a nice front air dam, the 17-inch wheels and tires, or the sport seats. OK, now let's say the dismantler's phone number is on your speed dialer. He feels sorry for you, so he cuts you a deal on these parts-- only $3,000, for a total investment of $15,500 to build your own M3. And all this assumes you will incur $0 labor charges doing all the work yourself.

Guess what, Thy--you can just sell the 325is and buy a competently maintained M3! Why build it yourself when BMW has already built zillions of them? The U.S. version S50 engine in the 1995 M3 is a special version only used in this market. It was down 42 hp from the European version, used the VANOS system from the M50 engine, and used only one throttle body as opposed to six. Our version also had a less sophisticated cylinder head. The 3.0-liter U.S. S50 is essentially a "stroker" version of the 2.5-liter M50, with hot cams and a forged crankshaft.

E30 Fuel Pump Scoped
My problem started when I heard a whining noise just in front of the left rear tire after driving for a few minutes. I believed it was the fuel pump and changed it along with the fuel filter and most of the fuel lines as they were all cracked and hard. The problem was still there. After about five minutes of driving the pump would whine. A Dutch mechanic told me it was a bad pump and I returned it and installed another new one. I had the mechanic set the timing and fuel ratio. The car ran fine then. Well then everything went wrong and to keep it short I found a bad coil wire and fixed that. I also ran the fuel down low and filled up with premium gas. Now the car starts and goes 1/4 mile then jerks and sputters until it is warm. The whining comes and goes. I have had to leave it parked. The car is not worth much and I only need it for one year. I am curious as to if the fuel regulator would cause the fuel pump to whine?
Donald Hulett
via the Internet

It's not the fuel pressure regulator. I suspect what you are hearing is fuel cavitation caused by failure of the auxiliary or "helper" fuel pump located on the sending unit inside the fuel tank. Diagnosis is simple. Remove the rear seat bottom and remove the fuel sending unit access hatch. You will see the top of the sending unit assembly, with a wiring harness and two fuel hoses. Run the engine, and use a mechanic's stethoscope to listen for the auxiliary fuel pump. You can also remove it for bench testing, but sometimes they work fine until they are immersed in fuel. The fuel resistance is just enough to stop the pump because the mechanism is worn out. Also clean the fuel pickup screen at the bottom of the sending unit.

You should also replace the fuel filter any time you replace the fuel pump. I suspect you've got a tankful of dirt. Inspect the fuel tank contents while the sending unit assembly is out, using a flashlight (not a cigarette lighter).

You should have a new O-ring seal ready for the sending unit assembly before removing it. It's also possible that the drivability problem is completely separate from the noise you are hearing.

E30 Tach-no-meter
The other day the tachometer and vacuum gauge in my 1987 325i quit working. Do you have any ideas of what the problem might be?

It could be the instrument itself, but I think the problem is more likely the instrument cluster motherboard. I recommend removing the instrument cluster so the motherboard can be inspected for any obvious problems like scorch marks or melted parts. Replacement motherboards are available from BMW. The instrument itself can be refurbished by

I need to know where I can get an M3 engine to swap with my engine. Also, where can I find and good gearbox to swap from automatic to manual.Dre
via the Internet

Go to and search "BMW dismantler." Also check out and

Replacement Battery Choices
I have a European-specification 1988 320i, and was wondering what type of battery would be available here in the United States. The vehicle is not listed in the parts catalog as having been imported in 1988.
via the Internet

Replacement original BMW batteries, which are very expensive, do not seem to live long. It's not uncommon to hear of failures after only two or three years. For this reason, when it's time to replace an original BMW battery, we'd rather turn to an aftermarket alternative for cost savings and/or greater durability.

The problem is that modern BMWs must have vented batteries due to their mounting locations, usually in the trunk or under the back seat. Vented batteries have a provision for a vent tube, which leads outside the car and functions to vent potentially explosive gases from the battery compartment. Failure to install a properly vented battery in these cars can result in a battery explosion. Underhood battery mounting locations do not require a vented battery. For aftermarket replacement BMW batteries, we've always preferred Interstate Batteries (, usually the Interstate MTP-91 for most contemporary BMWs. The MTP-91 has a provision for the battery vent.In the case of this car, I would recommend an Interstate MTP-91 battery. If it is mounted under the hood, then there is no need to employ the vent feature.

Automatics Suck; Manuals are Cool
I just bought a used 1992 525i BMW, my third BMW. The car drives very well on the highway, it's clean inside and out, and well maintained, but when I'm on local roads, using lesser gears, it does not kick into the next gear smoothly. It drags and eventually it will kick in. Today on my way to work, TRANSMISSION PROGRAM appeared in the multi-information display and that gave me a lot of concern. Do you think I've been sold a lemon or do you think is can be fixed with no major problem?
Kafayat Danmole
via the Internet

It depends upon your definition of "major problem", Kafayat. It is possible there is an electronic problem with the transmission, or that it is low on automatic transmission fluid (ATF), or that an ATF and filter change may cure things or at least ameliorate the problem. However, if I had to guess, I'd say you've simply got a worn out transmission there, which will need to be replaced.We tend to see BMW automatic transmission failures between 80,000 and 120,000 miles. BMW manual gearboxes are far more durable, given appropriate oil changes and using a high quality synthetic product.

I recommend you have this transmission diagnosed at a BMW dealership or an independent BMW shop with experience with automatic transmissions. At replacement time, I recommend only original BMW rebuilt automatic transmissions. If you are offered a choice between the "value line" transmission and a more expensive one, pick the "value line." There is no difference except for price.

Best Way to Improve Performance
I got the family 318i for my 16th birthday. I am 18 now and I was wondering what I could do in terms of performance. I am really clueless on this sort of thing but I have been fishing around on the Internet and, well, I haven't found much to help me with my specific car. Also, there doesn't seem to be many performance parts for BMWs in Corpus Christi, Texas.

I was wondering if an engine swap would be possible and if so what would it take. If not that then what else could I do? Any parts recommendations and tips would be most appreciated. Of course, I will be working on a limited budget but I would like to keep my car for a few more years.
via the Internet

Want to know the absolute best way to increase the performance of any car? It's to increase the performance of the driver. My best advice to you is to join the BMW Car Club of America ( and attend a local chapter driving school. In fact, attend about five of them before spending any money on performance upgrades. Short of supercharging (, there is not a great deal of performance to be squeezed from the M42 engine. Does this car have an automatic transmission? If so, I'd simply drive it until you can afford to replace it with something more sporting. For what you'd spend on setting up a 318i automatic with a 5-speed manual gearbox conversion and the 215-hp from supercharging, combined with the value of the car, plus the suspension mods required by the power, and you could almost buy a halfway decent used M3. Now, if you had something more sporting to begin with, like a 318ti or a Z3, our advice would be different.If the car is a five-speed manual, see if your budget will allow a Conforti chip and a Supersprint exhaust system. This should net you about 15-20 hp, which is not much but a significant difference on an engine so underpowered to begin with.

Dump that Slushbox
I was wondering what would be needed in a automatic transmission to manual gearbox swap in a 1997 Z3 1.9, how much it would cost, and where I can find the parts and service.
Dwan Dwans
via the Internet

Good idea. The car would probably love you forever, like removing a thorn from a lion's paw. You would need the gearbox, flywheel, clutch parts, pedal assembly parts, interior console parts, shifter assembly, driveshaft and the engine electronic control unit. The original could be reprogrammed, but then you would need to find a manual Z3 1.9 to bring to the dealer with the subject vehicle so it could "donate" its programming.

Some parts, such as the clutch parts, should be purchased new. Used parts can be purchased from any BMW dismantler. A good BMW dismantler would be able to sell you a package deal with everything you need. Check out and Cost depends upon labor charges in your geographic location. I would estimate labor time to be approximately 20 hours.

You would need to find an experienced and well-equipped independent BMW shop to perform this swap. Dealerships would probably not be interested. To find a good independent, your best bet is to join the BMW Car Club of America ( and consult the advertisements in your local chapter newsletter, attend chapter events and get word-of-mouth recommendations from the chapter technical representative and your fellow club members.

325Ci Tweaking
I'm looking to improve airflow on my car for better performance. I have a K&N air filter and a B&B performance exhaust. I've been informed that getting the Dinan air intake can't be done without the software so that's $800 for what, 10 horses? I hear that dropping the stock resonator is not as expensive and it gives some extra boost, but my question is do I replace it with an aftermarket unit or leave it resonator-less? I am not looking for a louder system at all; I don't care about a loud sound. What brand would you recommend for an aftermarket resonator, and what's your opinion about the catalytic converter?
Jordan Leitner
via the Internet

Short of supercharging, there are not great power gains to be had from this engine. BMW has optimized it that well. Forget about removing the resonator if you're not looking for a louder exhaust note. With the resonator, it will be incredibly loud. The catalytic converters cannot be removed without violating federal law.If you want to consider supercharging, I recommend you visit

Due to the difficulty in extracting signficant power increases without forced induction or other big money mods, contemporary 325i/Ci buyers need to flesh out the issue of whether they will be able to live with the power level of the 2.5-liter engine BEFORE deciding not shell out the additional money for a 330i/Ci. The 2.5-liter engine is perfectly fine for drivers who don't mind spooling up the engine to get what they want, but drivers addicted to low-end torque and beholden to 0-60 and stoplight-to-stoplight acceleration need the 3.0-liter engine.

Australian E21 320 needs help
I have a 1977 BMW 320 that cost only $2,000 Australian, and I want to know if there is anything much I can do to help it make more power. I really don't want to go the turbo/supercharged route, as I think that's sacrilege. One idea I did have was see if I could fit a later model engine (possibly a 6-cylinder M3), but I'm unsure if this is a viable option. Also, I'm wondering if 15- or even 16-inch wheels will fit it, without me having to modify the wheel arches or anything.

The current engine is a tired old 2.0-liter three-speed automatic (original) with no idea how many km on the clock--the odometer has stopped on 376,098km. The body is in excellent condition, with only one minor rust spot on the boot-lid (trunk for you lot), one on the driver's door (right-hand side), and one on the bonnet (hood). The only real problem with all this is I am a student, and so I don't have much cash, and no insurance agents want to cover me, as young drivers in European sports cars are apparently liabilities. If this M3 engine does indeed fit my vehicle's engine bay, would I be correct in assuming that I will have to put in a newer five- or six-speed gearbox?
Darwin, Australia

I can't tell from your letter whether you have a four- or six-cylinder 320, as both were available in Australia, and both have 2.0-liter engines. There was also the 320i, which is a fuel-injected version of the 320. That affects my advice, but I'll try to wing it just the same.

First, the M3 engine conversion is possible, but forget it if you don't have much cash; you'd need quite a bit. It's not just the engine--you'll need the radiator, exhaust, electronics, gearbox, custom driveshaft, and a custom differential installation if you want to have a speedometer. And your speedometer would have to be reworked to electronics. Then you'd need rear disc brakes and a full suspension upgrade. By the time you were done, you could have an M3 engine with the M3 it came in wrapped around it. Besides, a 320 is a perfect car to learn how to drive. Driving, even fast driving, is 95% suspension and brakes and 5% engine.

Now, if you have a four-cylinder carbureted 320, you'll want to remove the existing carburetor and air intake system (especially that whole Australian-specification zyklon pre-separator--what was that all about?), and replace it with a Weber 32/36 downdraught carburetor and a K&N air filter. Remove the original distributor and replace it with a Bosch ID48X rebuild, which is a mechanical advance unit for a 1972 2002ti/tii-- the best one BMW had. Also buy a Bosch blue ignition coil. You'll now have about another 20 hp, which is a big gain in a 320.

If you have a four-cylinder fuel-injected 320i, get the same distributor and ignition coil, and set the percent CO to about 2.2. In either case, if you can score a set of exhaust headers for a RHD car, so much the better. Use an exhaust manifold gasket with integral heat shield for a 1984 318i (E30).If you have a six-cylinder carbureted 320, then the performance parts are pretty much non-existent. Tune it up and be happy. Both engines require valve adjustments and tune ups about every 20,000 km.

Put your money into the brakes and suspension. I'd recommend Ferodo brake pads, Bilstein sport shocks, and H&R coil springs for the four-cylinder cars; there are no springs currently available for the six cylinder version. Or, at least not here. I'd also recommend a set of larger anti-roll bars such as Supsension Techniques offerings.The E21 3 Series BMW has a unique wheel offset so nothing but original 13-inch wheels will bolt right on and work correctly. However, small hub-centric spacers (5-8mm) can make E30 3 Series 14- or 15-inch wheels work. Your correct tire sizes are 185/70-13, 195/60-14, or 205/50-15. H&R makes 8mm spacers and longer lug bolts that will work. Now, regarding that K&N air cleaner if it is applicable, you need to understand the specialized maintenance required by an oiled cotton gauze filter. The element is oiled cotton gauze, not paper. When the filter is dirty, you or your technician will have to remove the filter, soak it with K&N Air Filter Cleaner (no substitutes), painstakingly wash the element with water (never use parts cleaning solvent on a K&N filter), wait for the element to air dry, re-oil the element just so--not too much, not too little--using K&N Air Filter Oil (no substitutes), wait for the oil to distribute itself throughout the cotton gauze element, and then reinstall it. This is not as big a deal as it may sound, especially if you keep two filters and rotate them into service, but if you aren't going to perform this maintenance work yourself and your technician isn't interested or trustworthy enough to do it, then keep the stock BMW air filter. It works just fine. With a Weber carburetor, this may require an adaptor.

Last, you need to ditch that godforsaken automatic transmission and get yourself a proper manual gearbox before someone thinks you wear dresses in private. I'd convert to a manual gearbox before anything else.

Reinventing the Wheel...Again
I have a 1993 316i and I am thinking about converting it to an M3. I would like to know if the chassis of my car is the same with M3 and if I will have any problems with the stability on road or about fitting the parts (engine, gearbox, etc.). I am ready to buy a 1997 M3 3.2-liter and put all parts on my car, except its chassis of course. (I need the VIN of my chassis; this is the reason for doing this conversion.)

I assume you are doing this conversion in order to save money on insurance or taxes. This is about the only way it would make sense over just driving the M3. I hope it is legal.

The chassis is different, but that doesn't mean you can't install the drivetrain, suspension, brakes, aerodynamics and other relevant parts. It will be an enormous job, so I hope you have a good place to work on the car, many tools, good BMW knowledge and above average mechanical skills. This conversion is much more than just the engine--in order for the car to drive correctly, you'll need the entire drivetrain, suspension, and brakes from the M3. I suppose you can take the 316i parts and put them on the M3 then!

E21 Parts Interchange
I was recently given a 1983 320i. In my quest to fix this car, I would like to know if any parts from other 320i models will interchange. Anything from 1977 to 1983 320is or any other models--interior, exterior, engine, etc.
Seraphim Nichols
via the Internet

Well, it depends upon your definition of "interchange." Theoretically, all the parts interchange, but many of them are different. The biggest difference lies in the drivetrain between the first and second generation U.S.-specification 320is.

Generation I lasts up to 09/79 production, and used a 2.0-liter K-Jectronic CIS-fuel injected M10 engine backed by a Getrag 242 four-speed manual gearbox and a 3.64 differential (limited-slip optional).

Generation II starts at 09/79 production and used a 1.8-liter K-Jetronic non-CIS fuel injected M10 engine. From 09/79 up to 09/80, the gearbox was a Getrag 245 five-speed overdrive with a four-bolt output flange. From 09/80 up to 09/82, the same 245 gearbox was used, only with a three-bolt output flange. But from 09/82 production-on, BMW installed the lighter Getrag 240 five-speed overdrive gearbox.

There are four different 49-state exhaust systems: Generation I manual, Generation I automatic, Generation II manual, and Generation II automatic. However, there are only two rear mufflers, Generation I and II. Whack-job California, predictably, has its own funky exhaust E21 parts.

Note that four different driveshafts are used in the U.S.-specification 320i: Up to 09/79 (four-speed gearbox), from 09/79 to 09/80 (Getrag 245 five-speed overdrive manual with four-bolt output flange), from 09/80 to 09/82 (Getrag 245 five-speed overdrive manual with three-bolt output flange), from 09/82 (Getrag 240 five-speed overdrive manual), and last and least, the automatic transmission driveshaft.Due to the overdriven fifth gear, Generation II U.S. 320is use a 3.90 differential, and again limited slip was optional. It was included with the S-package, which was only available in Generation II.

Up to 09/77, Generation I U.S. 320is used excellent large vented front brake rotors and two-piston ATE calipers. From 09/77-on, both Generation I and II units went to non-vented front rotors, and different strut housings, hubs, and calipers. The rear drum brakes are all the same.The fuel delivery systems went though at least three changes, although this is unlikely to affect your work unless you need new fuel tanks. If you do, you should buy them new from BMW and make sure you give the dealership your production date, which is located on a sticker in the driver's door-jamb.

Suspension-wise, the design is all the same regardless of year. But Generation I cars tend not to have a rear anti-roll bar. Shock absorbers were horribly underdone on all U.S. 320is, and they benefit hugely from a set of Bilstein HDs (with stock coil springs), and, if you want, a set of aftermarket anti-roll bars.

There were interior changes made in nearly each year of production, relating to the dashboard, instrument cluster, and center console. However, any configuration can be installed in any 320i. As far as mixing and matching, you're on your own there. It would be a trial and error process, probably with lots of error.

All 320i wheels are the same size: 5.5x13-in. with a unique 18mm offset. You can get into a lot of trouble and waste a lot of money trying to fit larger wheels and tires on an E21 3 Series. It is certainly possible, but if you don't know what you're doing then you're going to need to follow professional direction specific to what you want to do, or the thing is going to be all jacked up. If this is just a "driver," then trust me when I tell you to stick with the stock wheels and 185/70-13 tires. Plus-one sizes are 195/60-14 and 205/50-15, but the trick is all in the offset, which would likely have to come by way of hub-centric spacers--it's not easy. Plus, if anything is off or not exactly "true," you'll experience the dreaded E21 front suspension vibration at 50 to 60 mph. Do not scrimp on tires, either, or it will shake. The tail light assemblies changed from 09/79-on as well. I think that's about it, at least for the big stuff.

Google for Bimmers, Part II
I have a 2001 BMW 330Ci, which I would like to supercharge, but I can't seem to find a system for my car. I have read an article on the Ralph Kehlenner's conversion and another article in a different magazine. You guys are the experts--can you please point me in the right direction?
Ray Haniff
via the Internet revealed your supercharger in less than three seconds:

We have experience with Active Autowerke in Miami, and can recommend their products without reservation. The nice thing about supercharging a 330Ci is that the factory suspension and brakes are so tight and strong that it is not, in my opinion, always necessary to upgrade the rest of the car, depending upon your service demands.

Importation Costs Lots
I would like to find out the cost on converting a 1994 518i from German specification to American specification. It already has ABS brakes and catalytic converter.
Billy G. Locklear
via the Internet

From your letter I'm going to assume you want to ship the car to the United States and register it here. The cost is quite a bit; figure on upwards of $7,000 for inspection and certification, not including shipping. However, not much work actually needs to be done on a contemporary BMW that already has a catalytic converter and U.S.-specification crash bumpers. It's mainly a question of removing the vastly superior German-spec headlights and replacing them with lackluster U.S. version lights--best to do that before you ship the car, so you can keep the good parts and install them later. A conversion garage will not give them back to you. The car also needs the U.S. bumper covers that incorporate side marker lights.

The only glitch I foresee is that the 518i--a 1.8-liter four-cylinder version of the E34 5 Series--was never imported to the U.S., so I'm not sure how they'll compare it to those that were. It probably won't matter. But at the end of the day, I think you should consider that there are oodles of E34 5 Series cars already in the United States that do not need to be imported or certified.

Visit for detailed information.

Upputtender der Windows
I have a money pit called the BMW 633csi and was wondering if you could tell me a manual way to put up power windows that do not function.
T.J. Dellatorre
via the Internet

To get those windows up, you'll have to fix the problem, T.J. The first step is to make sure you don't have a blown fuse controlling the power window circuits. If not, the second step is to make sure you don't have faulty power window switches. Remove the switches by prying them out of the console using a small screwdriver or similar implement. Unplug the harness connector and for power at the pins using a test light or a digital voltmeter.

If you find power, clean the switches by dowsing them with electrical contact cleaner, refit the harness and try the switches. This usually fixes the problem. If there is no power and no blown fuses, then you have a wiring problem but this is unlikely.

If you have power at the switches and you cleaned them but still have no window function, the possibility exists that you have a bad switch. They cost about a dollar at the average BMW dismantler, so you might want to get a known good one as a tester.

If the switches are all good and have power, then you have seized power window motors or perhaps a broken regulator. Your regulator on the driver's side may be worn, but the most likely the problem is the motor(s). With the older motors, sometimes you can fix them. Sometimes the internal lubricant dries out and the electrical part of the motor does not have enough torque to spin the mechanical part. Disassemble the motor, clean the parts, and coat everything with some nice grease. It might work. If not, then you will need to purchase replacement power window motors from BMW.BMW now has a repair manual on CD for the E24 6 Series, part number 01 56 0 030 285, available from any dealership. The Historic Vehicle Parts CD, part number 72 00 0 301 255, will provide you with parts information.

There's a price to be paid for owning any car, T.J. You can perform whatever repairs your 633CSi needs, replace it with another used car that needs different repairs, or replace it with a new car and pay interest and depreciation up front. We pay one way or another.

Timing Query
I have just bought a 1996 BMW 318ti compact. This is the first Bimmer I've owned. It has done 96,000 miles. Does this engine have a timing chain or belt and when does it need to be replaced?
Jo New

The M44 engine has a timing chain. Replacement interval depends on wear, but normally shows up around 150,000 miles.

You Never Forget Your First
I have a 1992 318is. It's my first car and I love it. I've started to have problems with it, including the radiator, water pump, and some knocking noise from beneath the car. I would like to do a lot to this car, but I don't know where to start. Having things in mind and jumping ahead of myself made things a lot more confusing.

I've thought of buying a new car like a Nissan 350Z, but I think I should keep this car because it's already paid off. I have done a lot of research and made a list of things to do, which includes overhauling the engine, Downing Atlanta supercharger, adding a limited-slip differential, overhauling the manual gearbox, new clutch including resurfaced flywheel, bigger brake conversion, and a Bilstein suspension setup.

I wonder if I get a Jim C chip now, will it affect the Downing Atlanta supercharger when I have the chance to buy it further down the road? Also, I wonder if doing these things would affect the chances of passing a smog test. If so, is doing all of these things worth it? Or should I invest in converting it to a M3 engine?
via the Internet

You never forget your first Bimmer, Con. Many of us also spend way more than we should restoring our first, in part because we love the car and in part because we don't know what we're doing yet.

The problems you've had--radiator, water pump and the knocking noise (that was rear shock mounts, right?) are typical E36 3 Series problem areas. However, the M42 water pumps are much stronger than the six cylinder water pumps, so I'm going assume your friend there has many miles under his body side moldings. Attached is a short article on enhanced BMW maintenance, which should help you to preserve things.

There is much to be said for working with the car you already own rather than buying new when cash is tight--and for most of us, cash is always tight. For example, the unknowing may scoff if you execute a $600 repair on a 1992 BMW. Remind them that the monthly finance-to-purchase payment on a new German car would likely be at least $600--month after month, for several years. At the end of the day, there's a price to be paid for driving a car, and the price is higher for cars that drive well. You can pay when they're new or pay when they're mature, but you're going to pay.

If your engine and gearbox are in need of rebuilding, then this is going cost a great deal of money, especially if you want to follow on with a Downing Atlanta supercharger, a $4,000 expense right there. Con, let me tell you something: The M42 engine is not powerful. You can supercharge it and get about 215 hp out of it. The average self-respecting minivan today has more than 215 hp. This does not mean the M42 sucks--quite the contrary; it is a very good, if underpowered, BMW engine. But the 318i is a momentum car that encourages the driver to learn the benefits of momentum driving, working the gearbox, and carrying speed through corners. It is not and never will be a stoplight racer; that is not the nature of BMWs.

Sure, you can install an M3 engine--and drivetrain, and suspension, and wheels, and tires, and brakes, and aerodynamics, and interior. Or you could just buy an M3. It's a wonderful thing--BMW has already built the car, so you don't have to! BMW created so many E36 M3s you can't stop fast without one bumping into you from behind. And they are falling in price. The 1995 model year M3s are falling faster, because people stupidly want the staggered wheel and tires sizes from the later cars, not realizing that the original version is better.

My advice is, if your engine and gearbox do not need to be overhauled, then keep the engine in good tune and service the manual gearbox and differential by resealing any leaks and changing the oil in them to Red Line MTL and Red Line 75W-90 ( Install a short shift kit; you'll love it. If you need a clutch job, do it. You can't resurface a dual mass flywheel; just use 600-grit sandpaper on a DA sander and clean it before reinstallation. Install that Jim C. chip and forget about the $4,000 supercharger if you can't afford it because yes, Downing Atlanta includes their own chip with the kit. Do basic maintenance to sort the car out--change the brake fluid and make sure the front and rear suspensions are up to spec. When you have the money to spend, buy a set of Bilstein Sport shocks, aftermarket sport coil springs, E30 front control arms for the stronger ball joints, E30 M3 offset front control arm bushings, E46 M3 rear trailing arm bushings (tighten with vehicle in normal operating position, with the short springs installed), and install a set of large anti-roll bars. Buy the lower front X-brace from, and also their anti-roll bar reinforcements. Engine wise, the chip and a sport exhaust system is about all you can do, and it doesn't make much difference with the M42-- maybe about 10 hp or so. But you'll feel it, because the engine is so underpowered to begin with. When you need brakes, upgrade the rotors to ATE Power Discs and get some cool brake pads. I like Ferodos (

Cap that off with a set of very serious tires--you can even mount them on the stock wheels. Check out the Yokohama AVS ES100 in 205/60-15. Even in this size, it will outperform many other larger tires.

Now, enjoy the car and don't listen to people who harp about its relative lack of power. You will become a better driver by learning momentum driving on a lower powered car. You will also be grooving on about 32 mpg. Then later, if you want, buy a higher powered BMW like an M3 and sell your 318i.

This is the road to not overspending on your first BMW!

Perhaps a Justifiable Engine Swap
I have a 1992 E36 318i 5-speed. I have done many mods, from a Hamann body kit, fiberglass interior, racing seats, to a complete coilover suspension. I know I've been told it's too much to put into a 318i. But it's what I had to start with. Everyone else was doing Hondas but I wanted something different. My problem is that I have the original 1.8-liter M42 engine still.

I want the 1995 S50 M3 engine because of OBD-I, but I am in the dark about the swap. I do everything myself; it's the only way to learn. My dad used to build racecars for a living so I grew up around cars. I've spoken with a local foreign car parts store/shop. They told me that it wouldn't be that hard. All I would need to do is swap the motor, gearbox, ECU, and instrument cluster. They said that the differential and all the rest would be OK. But I don't know if I believe that.

The other option I thought of was supercharging the M42 1.8 that's in the car now.
Darrell Bellar
Huber Heights, OH

Engine swaps are rarely worth the time, money, and effort vice buying the car with the engine you want already installed. However, once you've got so much into other modifications on a given car, the pendulum starts to swing the other way, perhaps in favor of an engine swap. Relatively speaking, you've picked a fairly straightforward swap. You'd need the engine, radiator, ancilliaries, engine harness, ECU, and instrument cluster. Of course, you'd also need a complete exhaust system and the rear valance panel might have to be modified to accommodate the M3 tailpipes unless you've already fitted a coffee can back there. You can actually use the smaller gearbox in the car now--it'll bolt right up to the S50. How long it will last is a different question. Same for the small housing differential.Depending on your front shocks and springs, you might need to upgrade them too because of the extra weight. If you're running stock 318i brakes, you'll definitely want to upgrade there, at least to M3 brakes.

Supercharging the M42 engine means about 215 hp ( and about $4,000. Bear in mind the newest S50 is now nine years old, so you may be looking at rebuilding an engine, too, especially if you want to modify that, as well. But a normally aspirated S50 can produce about 300 hp if you have a healthy VISA card. Speed costs money, Darrell. How fast do you want to go?As with any modified E36, I would recommend the rear suspension mount reinforcement upgrade from These cars sometimes crack apart in the back. Although installing the reinforcements is a huge job, it's worth it if it keeps your car from disintegrating.

Facing Reality
I have two questions:

1. I own a 1991 E36 316i with M40 engine (99.23 bhp), and that's a problem because the M40 engine uses a method of metering the air only to idle to 3000 rpm, after this the air is not metered and any intake flowing more air than the standard setup causes the engine to run lean as it uses pre-programmed fuel curves. This leads to lost power and increased emissions because the air/fuel ratio is wrong! What do I have to change, or from which BMW should I take the necessary parts to address this problem? I know it would be cheaper and easier to install a more powerful engine, but I want too get the most out of this 1.6-liter engine.

2. This question is actually from my friend, who owns the same BMW as I do. He would like to build in a BMW 318is M42 engine (140bhp), and he would like to know if that is possible, and what else should he replace?
Ales Kasjak
via the Internet

Ales, you should listen to your friend. Trying to get more power out of an M40 engine is like giving your grandmother a boob job. The modification would be counter to the intended purpose of the engine (or grandma), and the money would be better spent on a more suitable subject.The M42 is also not exactly a stellar performer, although it is a very robust and durable engine. You don't mention your country, but from the fact that you have an M40 engine I can assume it is not the U.S. If the M42s in your country have knock sensors, then you may be able to install the excellent Downing Atlanta superchargers available for the later M42 and M44 variants. Check out for more information. This would be the utlimate M42 modification, as well as the only one that really makes a great deal of power output difference.

Island Bimmers
I live on Aruba. I bought a 1991 M Technic 325is. I want to know if you have any information about this car.

Sure do. The M Technic package included excellent high-speed aerodynamic parts including a front air dam, side skirts, rear valence panel, and a large two-piece rear spoiler that was a smaller version of the one on the E28 M5 and E24 M6. Also included are upgraded shock absorbers and coil springs. The springs are about 10mm lower than the standard springs.

In the U.S. market, the E30 M Technic package was only available on late production 1991 and 1992 325i convertibles. It was quite expensive, with the body parts alone costing over $3,000. You can still buy most of it, I believe.

Supercharging the M Roadster
I have a BMW M roadster 3.2-liter with 321 hp. I installed a supercharger, and I am looking to make some modifications in the cylinder head. I would like to know the benefits of cylinder head porting and new camshafts in terms of horsepower and torque.
Hussain Habib
via the Internet

Assuming you have installed a Dinan supercharger (, that is generally regarded as the most power we can get from the S54 engine and still maintain durability and reliability for street use. Once you go to forced induction, the pressure does all the work for you, and things like performance camshafts and cylinder head porting take sidestage.This cylinder head comes from the factory very clean--there is not much porting to do.Another thing is that the 321-hp engine is at the limits of the E36 chassis, especially in the rear. The E36 BMW chassis is inherently weak.

Now, if you had not supercharged the engine and you wanted a camshaft upgrade, Schrick has one. Visit and click on engines/schrick camshafts. The power gain is 15 hp, with no loss in low-end torque.

Tired 320i Turbo Isn't Done Yet...
I am writing you to see if you could lend a helping hand as to where I might turn up some more go-fast parts for my 320i. It's a Callaway turbocharged car with a Garrett T-36 instead of the KKK turbo. Current modifications include Cup racing seats, Blitz b.o.v,, Turbo XS boost controller, TiAL 36mm waste gate, and some different driving lights that I fitted because the old ones were crap. It also has all of the original stuff from Callaway, like the microfuel controller and in-car boost controller which is inoperable, and some kind of basket weave 15-inch three-piece wheels on the back and stock as far as I know on front.

I would like to drop it some and set the suspension up for drifting but I can't find anyone who still has sway bars and suspension stuff for the car like strut tower braces and the like. I would also like to do a roll cage and some lighter larger diameter wheels. All that being said I come to the body. The floorboards are on their way out, so I would like to get a rust free donor car and swap it all out this winter. What do you think?
Sam Clough
via the Internet

The first thing you should do is put the same size wheels and tires all around before you kill yourself! If those "some kind of basket weave" wheels on the back are actually BBS RS wheels in the correct E21 3 Series offset, then you have the Holy Grail of E21 wheels even if you don't want them. You can probably finance a whole set of wheels and tires just by selling those two wheels if they are in good condition.

The problem with wheel upgrades on the E21 is the unique offset. Back in the day, we could buy correct offset 14 and 15-inch wheels for the E21, and BBS was one company that sold them. But that was then and this is now. Today, to get new wheels to fit an E21, we've got to use spacers and longer lug bolts. Try not to use spacers any larger than necessary, as anything you do with wheels and tires beyond stock on this car is likely to create or worsen the E21's characteristic front suspension vibration. Your correct 15-inch tire size is 205/50-15, although some people stagger sizes 205/50-15 rear and 195/50-15 front to deal with the oversteer in this car, but if you're into drifting you'll want to keep them all 205/50-15. Anything larger than that on an E21 is just bling-bling, in my humble opinion. Check with and

Since you have a Callaway turbo, I suspect you already have shorter, firmer aftermarket coil springs and upgraded shock absorbers, probably Bilstein Sports. It's no problem finding performance parts for the E21, Sam. You can buy H&R coil springs from Turner Motorsport (, BMP Design ( or Bavarian Autosport ( They'll have Bilstein Sport shocks, too. BMP Design and Bavarian Autosport will also carry sway bars from Suspension Techniques. You can get the trick suspension parts for drifting and the roll bar from Top End Performance ( BMP Design also has front and rear strut braces for the E21. While you're at it, buy a set of BMP Design's polyurethane steering rack bushings for the E21. They are excellent, but a real bitch to install. A rust-free 320i, eh? Good luck, Sam. You'd be better off cutting out the rusted floor areas and welding in new metal. The only rust-free 320is I ever see are not likely to become donor cars.

Camber Quandary
I need help on a camber issue. My camber for rear right and left do not match even after maximum adjusting. The front also doesn't match, but no adjustment is possible. I went to a few tire shops but both also say this is a mechanic's job, not theirs; they have no equipment.Please advise. My rear now reads one side +2.5 and the other -.05--a huge difference. I want to fix it soon.
via the Internet

You didn't tell us what model and year BMW we're talking about here, so it's kind of hard to get a handle on the question. My guess is you have damaged parts at the rear, most likely a bent control arm, trailing arm, or rear axle carrier depending upon the model and year BMW. If possible, bring the car to a BMW dealership and have the rear suspension components inspected and measured. Then compare the measurements with the factory dimension specifications. However, if you are off that much, they'll probably be able to tell something is bent by looking at it.Now, that said, BMW only recently got onboard with camber adjustment. Traditionally, camber was not adjustable at all on BMWs without aftermarket parts that were of questionable durability on the street. It is normal for BMWs without camber adjustment to have uneven amounts of negative camber side-to-side. However, it's usually a question of less than 0.75 degrees.

Weber Carbs: Easier than iDrive
I have a 1972 3.0CS with dual Weber 32/36 carburetors. I've had it since 2000 and don't drive it much. I adjusted all linkages and had it sounding perfect at idle, CO at smog test was half of allowed in Colorado and right on spec. But the car is way too lean at 2,500 rpm. I just can't figure out what to adjust for that.

How do I adjust the two short (three-inch) linkages with the nylon cups at the end, how long should they be? How do I adjust the carbs so that at full throttle the two secondaries are open? I have new hardware on there so I can easily adjust the location of the arms on the main two shafts, but I'm lost on the small linkages and the rich/lean adjustments off idle.
Jim Connell
via the Internet

Your engine probably has dual Weber 32/36 DGAV carburetors, which are the most common Weber conversion for the early M30 engine. The first thing you need to do is stop guessing and buy the Haynes Weber Carburetor Manual, which is inexpensive these days. It's not perfect but it's better than nothing.

The two short linkages or control rods are adjusted simply so that there is no slack. These are factory BMW parts, so f you want the actual procedure buy the BMW Mobile Tradition Repair CD for the E9 coupe, BMW part number 01 56 0 004 535. You should have this manual for other work on this car, as well.

You say the engine is way too lean at 2,500 rpm. How do you reach that conclusion? Does it run well at that speed? If so, leave it alone. If it doesn't, you need to start over with the basic adjustment procedure, as there is only one mixture adjustment on these carburetors. Do you mean it runs lean at 2,500 under full throttle acceleration? If that's the case, then one or both carbs probably have issues with the accelerator pump diaphragm assembly or the throttle valves are not opening fully, which you alluded to in your letter. In that case, check for anything that prevents the secondary throttle control lever from fully activating the secondary throttle valve on each carb. There could be wear between the secondary throttle control lever and the primary throttle control lever, or there could be an issue with worn springs on the loose levers or the bush retaining springs. There is an adjusting stop screw on the secondary throttle, which should yield a gap of 0.05mm between the outer edge of the secondary throttle valve and the secondary barrel. There could also be incorrect float level adjustment.

If it gets to be too much, don't hesitate to take the car to an old school BMW technician with experience adjusting these carburetors, and ask if you can watch him at work. I'd recommend an independent BMW shop for this purpose.

E9 CS Coupe Revival
I have a 1972 E9 CS coupe with no rust. I know that's unbelievable, but there are downsides. It was repainted with a GM paint which is totally different from original, so I am not planning the desecration of an icon. Rather than remove and rebuild the original engine and four-speed manual gearbox, I lean toward replacing the engine with as late a fuel injected engine as is practical, plus a five-speed overdrive gearbox.

I have no wish to make a rocket ship of the vehicle, just to update engine reliability, increase fuel mileage, have at least 200 horsepower, and have emission controls in place which are effective and socially sound. My goal is to keep the project as simple as possible, e.g., no tin cutting to accommodate new manifolds, no exotic fabrications, no new holes in the transmission tunnel, etc.--just a reasonably straightforward swap. I am aware that I'm fantasizing in my oversimplification, and that there would be many accommodations necessary just to utilize the emissions controls, but I'm willing to do what it takes in the interest of having a reliable modern drivetrain.
J. Williams
via the Internet

Your letter doesn't mention how much money you want to spend on this project, your level of BMW savvy, or the nature of your working facilities and tool collection. What you propose to do is not straightforward, and will require a trial and error process--probably more error than trial. Unless you are intimately familiar with the E9, BMWs in general, and the BMW parts system, you're in for quite an ordeal--the sort of ordeal that, in my experience, sometimes never sees the light of day. Let me first try to talk you out of it.

Initially, there is much to be said for using the parts you already own. Assuming the engine and four-speed gearbox are in need of rebuilds, let's not assume that a replacement engine and gearbox would not be in similar condition. The newest 3.5-liter M30 engine and accompanying five-speed gearbox from an E34 535i is now eleven years old. It is an unfortunate reality that most people do not maintain their cars, and those who do rarely have drivetrain components for sale. So, the worst-case scenario is that you would toil endlessly only to wind up with two worn out engines and two worn out gearboxes. Moreover, it is a lot less expensive to rebuild a Getrag four-speed than a five-speed.Part of the beauty of a 1972 car, at least for most of us, is not having to worry about invasive emission control devices. You social conscience is admirable, but there may be aspects of this question about which you are not aware. A fresh 2.8-liter carbureted M30 engine in good tune is not a high pollution emitter. More than a 1993 535i? Yes. But the first indifferently maintained V8 Buick that passes you in blue smoke emits 5,000 times more bad stuff than your engine. I would put forth the proposition that rebuilding your 2.8-liter and ensuring it's in good running condition IS the socially sound thing to do.

The 2.8-liter M30 can easily be made to produce 200-220 hp in the course of a rebuild. I recommend 9.0:1 JE pistons in place the U.S.-spec units, a Schrick 284 camshaft, Stahl headers, a lightened flywheel, and duel Weber DGAV downdraft carburetors in place of the original Zeniths.Most people who want to covert a four-speed BMW to a five-speed overdrive wish to do so to lower engine rpm at highway speeds. As drivers, we have grown accustomed to cars that lumber along barely over idle speed at 70 mph or so. This is not the car you own, J. Vintage BMWs are designed to rev. This car has a 3.45 differential, which is just about the perfect performance gearing for a 1:1 fourth gear. If you install a five-speed overdrive gearbox, your effective final drive will drop to a 2.76:1 ratio. This means you'll be downshifting into fourth gear every time you want to pass someone or ascend a steep grade. Bear in mind we can do much to increase power in the M30, but what we cannot do is make it a low-end torque motor like an American V8. BMWs of this vintage are not about low-end torque.

If you convert to a later M30, you will have to mix and match oil pans until you find the one that works, wire the entire engine bay, rig fixtures for engine hardware, rig a larger radiator, custom build a driveshaft and the complete exhaust system, and mount the engine management computer in the glovebox. And that's just what I can come up with off the top of my head. BMW shops in California often have experience in this sort of thing due to their state air bureaucracy essentially legislating older cars out of existence. Shipping the car there would probably save money in the end.

Here are some Web sites: rebuilding, flywheels, engine rebuilds parts, engine rebuilds parts, engine rebuilds parts headers

E30 M3 vs. 325i
I'm a car enthusiast posting from the Philippines regarding the choice between an E30 325is and an E30 M3. Neither car is easy to come across here but they show up now and then in the classified ads. Whenever they do, they surely are overpriced. But I have made up my mind to choose between these two cars, as I am a big fan of BMW E30s. I will be limited to M3 availability, and might regret having to pay the price the seller asks for (at the very least $11,000 in terms of your market). Could you please give me some strengths of the 325is over the M3? I'm sure it still doesn't come close to an M3 in terms of performance, but is it still a great performing car?

If I do get the 325is, I plan on using the extra money modifying it with what you usually recommend (air filter, chip, exhaust, suspension, lightened flywheel, brake upgrades, etc.). What I really want to do is reduce as much weight as possible wherever I could. I'm also considering reducing the rotational mass of the engine later on. Is it really worth adding lightweight components such as pistons, valve retainers, rods, and pins, while still having an M20 engine? Any other engine components I could upgrade, like a lightened crankshaft? I want an engine which is lighter and revs more freely. About how high can I expect the M20 to rev with an aftermarket chip and the other mods?

Finally, regarding compression ratio on the 325is: What would be the highest ratio I could use (I think the stock ratio is around 8:1) while still retaining the stock camshaft and fuel injector sizes? Do I really have to change them?
Andrew Alarcon
via the Internet

The E30 represents one of the last real driver's BMWs in my opinion. With emphasis clearly placed on engineering and performance rather than styling, the car is the product of engineers in the traditional BMW way, not marketing weenies. I think the M Coupe was the engineering rebels' last gasp against the Empire, who wants BMW to be a luxury car manufacturer.

Although similar, the E30 M3 is a completely different car from the E30 325i. The entire drivetrain, suspension, brake system, body parts--even the body skeleton is different--massaged by BMW Motorsport for performance. (Today's BMW M was formerly known as BMW Motorsport. Enthusiasts joke that "M stands for Marketing.") Production numbers are extremely low. The street E30 M3 was built simply to homologate the car for European Touring Car racing, in which it was the most successful car in the history of the series. Street versions have an enormous following around the world, but their appeal was lost on the vast majority of U.S. market buyers, many of whom are impressed solely by torque and 0-60 acceleration, neither of which is the E30 M3's forte. As a result, two types of E30 M3s in the U.S. are most prevalent: scrappers that need $15,000 worth of engine rebuild and other work, and those that have been cut up into racecars. Nice, well-maintained examples bring big money--a lot more than $11,000--and prices seem to be edging upward. Finding one with less than 100,000 miles is pretty difficult.

The 325i is totally different in that God made zillions of them. It has more torque and feels faster at the low end than an E30 M3, but some 12 years after the last 1992 325i convertible was built for the U.S., it's now regarding as just another old car by the great unwashed out there. This means scrappers, lots of them, that need lots of work. However, they are also cheap and worth the repair investment in terms of performance and durability. The E30 3 Series is widely regarded, even among E36 aficionados, as the most durable and reliable 3 Series to date. On the downside, it's probably harder to find a pristine 325i than a pristine M3. Both will cost you lots.

Functionally, one of the biggest differences between the two car is that the M3 suspension was nearly perfect right off the showroom floor, whereas the 325i cried out for Bilstein Sport shocks, shorter, firmer aftermarket coil springs, larger aftermarket sway bars--and the big secret, E30 M3 offset front control arm bushings.The E30 M3's S14 2.3-liter DOHC four-cylinder engine is more race than street, making power in the upper end of the rpm range, and is not as durable as the M20. It also requires costly tune-ups and valve adjustments every 15,000 miles. Vibration from this engine kills intake manifold gaskets, motor mounts, and eventually even wears out the shifter linkage parts. However, the aftermarket and the factory have solutions to the gaskets and shifter. Rebuilding an S14 will run you upwards of $10,000. In the U.S. market, the E30 M3 runs a massive Getrag 265 five-speed overdrive gearbox spinning a 4.10 limited-slip differential. The 325i runs a smaller Getrag 240 five-speed overdrive and a 3.73 differential, with limited-slip optional. One of the biggest acceleration secrets for the 325i is a swap to the M3's 4.10 differential. The overdriven fifth gear makes either diff viable at higher speeds, although today drivers are accustomed to cars that lollygag along at 2,000 rpm--that is not the case with the E30. Remember, we're talking about Real Man Bimmers here, not status symbols.

In terms of which car to choose, it really depends on what you want out of it and how much you can spend to maintain it. Every part for an M3 that is not shared by the 325i--and that's most of them--will cost at least twice as much as the corresponding 325i part, usually more. I don't know what the parts situation is on the island, but I'd say you can plan on buying everything you need from the BMW dealer, and much if not all of it will have to be special ordered. You can't expect a dealership in the Philippines to stock E30 M3 parts.

I don't know how you drive or what you expect from the car, but a 325i will require a complete suspension upgrade along the lines mentioned previously to yield M3-like handling. The M20 engine modifications you're talking about mean a complete professional high performance rebuild costing upwards of $10,000. Mahle European-specification pistons for this engine are 9.7:1 compression, although JE can build you whatever you want. No camshaft or fuel pressure regulator upgrade is necessary, but why stop there? I would recommend a Schrick 288 cam. Many other special parts will be required to build an engine of this sort, so I would recommend you have it done in the U.S. and shipped to your location unless there are BMW performance engine building experts on the island.

Rebuild or Repair?
Is it better to get a rebuilt engine or have the existing engine repaired for $1,650? I'm looking at engine rebuild prices from $1,300 to $1,600.
via the Internet

You haven't given us much to work with here, Ben. What exactly is the problem with this engine? If you can get a complete rebuild for the same price as the repair, then why not get the rebuild? However, we suspect the price range you're quoting does not include boring the block and replacing the pistons with oversized units, so that's not a complete rebuild. On the other hand, we don't know if that work is needed on this engine, either.

E36 S50 Swap
I have recently returned from a brief deployment in the Middle East and was planning on buying an E36 318is. For this particular car, would it be possible and somewhat easy to swap in an S50 3.0-liter engine? I know I would have to probably put an M3 exhaust system on and maybe a new gearbox. What is your input?
Nick Ellert
via the Internet

Welcome home, Nick, and thank you for your service.Sure, you can install an S50--why would you want to? Why not just buy an M3 with the S50 already installed by BMW? If you think it's going to be cheaper to build it yourself, you are incorrect. It's not just a question of the engine, which, by the way, would bolt to your existing gearbox even though it is smaller. You'd be looking at a full brake and suspension upgrade as well to handle the extra power. Plus the M3 has better seats, better aerodynamics, 17-inch wheels, and the stronger gearbox.

More 318i Power
I have been trying to find a way to get more power out of my E36 318i but I don't have the money. I was wondering how much an E23 745i turbo engine swap would cost and if I could swap that engine in.
Daniel Lee
via the Internet

I'd say it would cost quite a bit, Daniel, but that's just an estimate. I've never seen an M30 engine installed in an E36, but there's certainly enough room and with enough money anything is possible. It wouldn't just be the engine, though, as no E36 gearbox will bolt to the M30; you'd need an M30 gearbox and, no doubt, a custom-made driveshaft. You'd also have to fabricate the shift linkage and the exhaust system.

The car would have weight issues due to the M30, probably best solved with a coilover front suspension in terms of hardware, but it would always be nose heavy. You'd have to upgrade the brakes to M3-specs or beyond to handle that much power, not to mention the rest of the suspension. Frankly, you'd be better off just driving the 745i.The best way to significantly increase power in an E36 318i is by supercharging. Check out Downing Atlanta at

Free-Flow Exhaust: Quiet Please
I own a 1998 BMW M3. I am in the market for a cat-back exhaust system. I understand that as a magazine that depends on advertisers for revenue youmay hesitate to recommend one over another. I've read the issue that covered many systems that are currently available. Also, I've seen the SuperSprint was chosen for the turbo M3 build-up.

My concerns are probably typical. I want a good sound, and understanding that is subjective, it's probably the main thing stopping my from writing a check today. I have read that the SuperSprint and Borla offered by Turner Motorsport are not as loud as, say, a UUC System U or TSE. Additionally, I don't want issues with fit or installation or a droning sound at steady throttle. The systems I am considering are SuperSprint, Borla, UUC System U, UUC TSE, and Active Autowerke.
Mike Ruth
Richmond, VA

You're right. Exhaust sound is entirely subjective, and that makes it extremely difficult to recommend one over another. However, our advertisers understand that we make recommendations tailored to a reader's needs.Mike, your well-written letter is sufficiently wary of exhaust sounds that we will recommend what is clearly the quietest system: the SuperSprint. Whenever quietness is key, look for a European-made free flow exhaust system. European exhaust manufacturers are constrained by noise legislation pushed through by the radical anti-car Greens parties. Still, there's that subjectivity--no warranties are given or implied.

Freshening a 325i
I was recently given an 1987 325is (6/87 production date) with an automatic transmission. The interior and exterior is in sad shape. The motor is relatively leak free and was just freshened up by your truly. I want to do the exterior with color keyed trim and bumpers. The chrome does nothing for this car. How do I find out what fits? I was told I was SOL on the bumpers, as they would require major modifications to make later year color keyed bumpers fit. Also, I want to add later factory wheels. Which ones will fit correctly?
Fresh Fish
via the Internet

You're far from SOL. It is true that the later (1988-1992) E30 bumpers will not work on this car without modificatons rising to the level that would pay for a 1988-1992 E30. But if you want to color key the existing parts that's no problem. All you need to do is remove the bumpers, center rub strips and end rubbers from the car and make sure they are squeaky clean. The aluminum bumpers themselves will have to be sanded or bead blasted prior to painting, and the rubber parts will require use of a flex additive in the paint. Regarding the bumpers, personally, I think they look best powdercoated flat black, which is often less expensive than painting.

You're less fortunate with the wheels, due to the 4x100 lug bolt pattern. Your choices are thus limited to aftermarket wheels or non-M3 E30 3 Series wheels (the E30 M3 used a 5x120 lug bolt pattern). The choice is "bottlecap style" wheels or BBS cross-spoke wheels, which came with the "s" cars like the one you have. Both are 14-in., and both will easily accommodate 205/60-14 tires including Yokohama's outstanding AVS ES100 high performance tires. If you want to do this on the cheap, I recommend you consider keeping your cross-spoke wheels and using 205/60-14 AVS ES100s. Other factory alternatives with 4x100 bolt patterns did not come on U.S.-spec E30 3 Series cars: the Star Spoke wheel and the BBS cross-spoke both came in 7x15-in. sizes, which can accommodate 205/55-15 or 225/50-15 tires. However, the only place you are likely to find either one is brand-new special order from BMW, at considerable expense. You can also check and for aftermarket wheel fitments.

More Weight, More Spring
I have a European-specification BMW 318i four-door sedan originally equipped with the M40 engine. I recently installed a European-specification 320i 2-liter DOHC M50 engine with gearbox, differential, wiring harness, computer, etc. Everything works well. My question concerns my front struts. My tires are 215/60-15 and they are touching the wheel housings. What front struts do I need to install to overcome this problem?
via the Internet

Your tire-rubbing problem is not the struts per se but the coil springs. You need coil springs for a 320i. You should also use the front struts for the 320i due to upgraded damping. I believe the rear shocks are the same, but the springs may not be. Investigate this at a BMW dealership; you may need rear springs, too.Also, I believe your correct 15-in. tire size is 205/60-15, but I don't think this is causing the rubbing problem.

BMW SMG: The Manual Gearbox Meets Rube Goldberg
I am driving a 1997 BMW M3 3.2 SMG cabrio with 131,000km. Lately I have experienced that sometimes the gear-position indicator on the dashboard starts flickering. Sometimes it goes away by itself. Twice, after stopping the car, it was not possible to drive away again. The car is in first gear on the dashboard but nothing happens when applying the accelerator. After some minutes the flickering goes away and the cars acts normally again.The gearbox oil level and electrical circuits check out OK. My BMW dealer has checked the computer, which states no failures. Can you give me a direction in which I should look for the problem?Charles Leeflang
Zeewolde, Holland

With sequential manual gearboxes, car manufacturers have taken what was perhaps the most dependable and durable transmissions in the world and turned them into electro-hydraulic Rube Goldberg contraptions. In one fell swoop, the manual gearbox went from dream to nightmare--at least, from a technician's standpoint. With this many electronics, electrics, and hydraulics, it is inevitable that cryptic failures would occur, and they do. BMW dealerships like to plug the car into their computer and read a fault code, which is great if the failure sets a fault code, but not every problem does. In these cases, the technicians need to employ good old-fashioned diagnostic snooping. This is what has to happen here. Or, you can wait until the problem is chronic, in which case it will still be present when the technician has the car in his service bay.

Meanwhile, I would recommend verifying battery voltage under static and loaded conditions, as a low voltage condition can wreak havoc on these electronic cars. But my feeling is this problem is electronic in nature. When it happens again, try shutting off the engine for 15 seconds or so, and then restart it. This can be like rebooting Windows on these cars.

Nitrous Oxide: No Laughing Matter
I have a 1994 production M3 3.0-liter which was equipped with a Hamann Motorsport package, including a chip and an exhaust system that increased the performance of the engine fron 286 hp to 330 hp. Now I'd like to install nitrous on the engine, but I need your help with this.Do you have any technical data on the Hamann Motorsport chip? Does it advance timing? Any recommendation how to install nitrous on this engine?
Thomas Szene
Perkasie, PA

Initially, the U.S.-specification 3.0-liter E36 M3 engine produced 240 hp in stock form, not 286 hp. I'm not familiar with the Hamann parts you installed, however I'm skeptical of their horsepower claim and I suspect it relates to the European-specification S50 engine, not the U.S.-spec engine. On the other hand, you didn't tell us whether or not you have a U.S.-specification car.In any event, most of the BMW letters we receive that mention nitrous oxide injection also mention "blown engine." So my advice is proceed very carefully. The only BMW parts company we're aware of that sells a nitrous kit for BMWs is Bavarian Autosport ( It is not a bolt-on deal; this kit will require expert fabrication and tuning tailored to each specific application.

Probably because nitrous is far less popular or common amongst Bimmer drivers, we do not have the bolt-in-gas-n-go kits that are available for the Fast and Furious crowd. My reading is that BMW enthusiasts tend to be more interested in consistent high performance over the long haul of ownership. To the extent they are into competition with their cars it involves time trials on road racing courses, rather than the sort of stoplight-to-stoplight racing that lends itself well to nitrous and that's so popular with the Fast and Furious kids.

RHD E30 Headers
I'm looking for a set of headers for a right-hand drive BMW E30 323i. Any ideas where I could get one and what horsepower gain I should expect?
Tony Patmore
via the Internet

That's a tall order, Tony. I'd recommend you visit in England, and see if they can point you in the right direction. If anyone will know, they will. The German tuners had E30 six-cylinder RHD headers at one point, but these cars are museum pieces to the Germans. We have no dyno figures on a stock E30 323i with RHD headers versus stock. However, I suspect the horsepower gain would be low-to-moderate and not dramatic.

Get with that Manufacturer!
I recently replaced the ECU in my 1995 BMW 318ti with a Haltec controller. The new controller works fine but the instrument cluster now does not. The fuel and coolant temperature gauges are behaving quite erratically. It appears to me to be a grounding problem. Apparently these gauges were grounded in the stock ECU. Anyway, I can't get a proper wiring diagram to tackle the problem. Can you offer any help?
via the Internet

My best advice is to contact Haltec. This sort of thing is almost to be expected when putzing around with BMW electronics; they are problematic enough in stock configuration. If Haltec cannot help, and in the absence of the services of an electronics engineer, I'd return the unit and put the stock ECU back in service.

Mini Voyages Abroad
I'm hoping you can answer a question concerning the Mini USA vs. European models. I would like to purchase a Mini here in the United States, however, I might be moving to Europe and was wondering how much difference there is between the two versions. Will service and parts be available? What kind of safety specification changes might be needed for a U.S.-spec Mini?
Seattle, WA

Much depends on which European country will be this Mini's new home. Usually, the only thing you have to do to register a contemporary U.S.-specification car in most European countries is upgrade the lighting to whatever standards exist in the country of registration. Germany, for example, requires you to install the far superior European-specification lighting. Germany also requires elimination of the side marker lights. Some parts of France require that plus yellow headlights. Some countries, including Germany, require a rear fog light. Other countries require no modifications at all.The same applies to parts and service. If you're in one of the larger European countries, it shouldn't be much of a problem. Find yourself in some of the former Eastern-bloc countries, and you'll be lucky to find a shop that can maintain a European-specification Mini, let alone a U.S. car. And of course you can forget about the warranty.

The Skinny on Mini
I'd like your opinion on upgrading the Cooper S. Should I buy an aftermarket kit from Mini Mania like the stage two, or should I use the John Cooper works kit and not buy MOMO seats?
Kit Keyser
via the Internet

Mini Mania has some very nice stuff, and to be honest with you I'd probably buy a lot of it if I had a Mini. But there's no doubt I'd go with the John Cooper works kit. I've seen it in action, and I know that a tremendous amount of R&D was put into it. There's also the historical aspect--it's kind of the right thing to do. And down the road when the parts are no longer available, that cylinder head will be worth its weight in gold. Well, maybe not that much, but it will be a highly prized item that will probably be responsible for more than one divorce after Ebay auctions of the future.

Seats are a totally individual choice. I like the sport seats in the Mini, and I'd only change them to reduce weight or to facilitate safety harnesses. Just make sure slider brackets are available for whatever seat you buy as this is sometimes an issue with MOMO.

God Makes Mustangs, Too
I have a 1984 BMW 318i. I want to put in a Ford 302 but I don't know where to find a conversion kit.
via the Internet

No problem, Chris. The conversion kit is called a Mustang, and it's as close as your local used car lot. But there's no need to install a truck engine in a BMW when you can buy the truck with the engine already installed!Seriously, there is no conversion kit and for good reason. A Ford V8 would totally ruin the car. It's way too heavy for effective weight distribution, and possibly for the engine carrier as well. None of the drivetrain components would work. Everything would have to be completely fabricated at great expense. For any purpose other than straight-line acceleration it would be a step backwards. And for straight-line acceleraton, it would make a great deal more sense to buy the Mustang instead.

Welcome to the Race Track
I have a 325is and have upgraded the rear brakes to 328iC assemblies. However, I find the pedal still going long and front pad wear excessive. In a two-day school at Road America I went completely through a front set of Pagid Blues while the rears barely burnished the rotors. Is there an upgrade for the brake master cylinder? The part number for the 328iC master cylinder is different from that of my 1992 325is. Will the 328iC master cylinder work on my 325is? Any other suggestions?
Ron Clarkson
via the Internet

Welcome to the track, Ron. It is not unusual to tear through a set of front brake pads in two days. Service demand is the primary factor, backed up by the track, speeds, tire type and size, ambient heat, braking style, cooling provisions, and cool down procedures.Regarding the pedal feel, probably what you've got there is a tired brake master cylinder, plain and simple, which you could replace with the original part number. Upgrades are always nice, but the BMW parts information doesn't tell us the difference between one E36 brake master cylinder and another, or whether they are interchangeable.

Project 325is Suspension: A Bit Much for the Street
In Part 4 of project 325is you were installing T.C. Kline suspension components on the car. You said, "For alignment specs, T.C. recommended the following: Front camber, 2-degrees negative for street, 3.5-degrees negative for track. As noted, this takes just minutes with the camber plates. Front toe, 1/16-in. total in for street, 0-1/8-in. out for track, caster, all you can get, rear camber, 1.5 to 2.0 degrees, rear total toe 3/16-in.

Because I don't have camber plates yet, but I know my camber is close to -2, I'm wondering if it's OK to just set the rest of the suspension to these specs accordingly. Is it safe on the tires and how is the turn-in and high-speed stability? Thought I ask before I do anything stupid. Hope I hear from you since T.C. Kline never e-mailed me back regarding this. Also, I wasn't able to find a source for the factory alignment specs for this E36 325is. If you have them handy can you e-mail them my way please?
Iliyan Palikarev
via the Internet

Dan Barnes, owner of Project 325is, has moved on to greyer pavement; he no longer writes for us. But before he left, Barnes told me that the T.C. Kline polyurethane components he installed were a bit much for the street. T.C. Kline's suspension setups are legendary at the track, but I tend to agree with Barnes regarding the street. I also think -2 degrees negative is a heapin' helpin' of camber on a street car. It's fine, not dangerous or anything, and will provide great cornering power. The trade-off will be some significant inside tire tread wear, though. I'd go with -1.5 degrees on the street--just my opinion.

There is no problem with setting up your suspension to Kline's specs and waiting until later to install the adjustable camber plates. Rear camber is adjustable on this car only with aftermarket adjustable control arms.All E36 alignment specifications are set forth in the Bentley E36 Service Manual ( It's too much to retype here, but you need this book if you're going to be working on this car anyway.

Alfa Who?
I have been an avid reader for years. I desperately would like to purchase a new Alfa Romeo, but obviously they are not available in the U.S. Is it possible to purchase cars not officially imported to the U.S.?John Beechy
via the Internet

It is possible, but not inexpensive. With respect to new cars in particular, personally imported cars may only be brought to the U.S. for racing or display purposes, and they may not be registered or driven on roads. There are, of course, certain ways around this. Car manufacturers can bring in non-conforming models for testing purposes, and car dealerships and others in the automotive industry may have "roving tags" than they can switch from one car to another. However, you have a long and expensive road ahead of you if you want to drive a new Alfa in the U.S.Intially, please visit this Web site: is tailored to BMWs, but marque really does not matter.

E36 M3 Stuff
I have seen some silver colored carbon fiber interior products. Do they make a silver-colored carbon-fiber hood? If not, is there a good source to buy one from for 1997 M3?Who do you recommend for upgraded brakes, including calipers? Is Brembo the way to go? I would like to keep the cost down a little.
Rick Brown
via the Internet

There are many companies out there building carbon-fiber body parts for the E36 3 Series, and if you page through an issue of European Car you will find most of them. A search on will likely reveal the rest. Bear in mind that not all of them will use the factory hood mounting and lifting mechanisms--some attach with hood pins.Carbon fiber is, well, carbon-fiber-colored. You can paint it any color you want, and not all carbon fiber is "finished" for a nice unpainted look. That stuff costs more.

You can't walk down the street without stumbling over an E36 M3 big brake kit. StopTech, UUC Motorwerks, Turner Motorsport, Active Autowerke, Bavarian Autosport, BMP Design--these companies all sell big brake kits for the E36 M3. I recommend visiting their Web sites and finding the one that meets your needs. Brembo makes great brakes, too, and don't discount the company as unaffordable without checking your particular fitment and comparing it with other kits.

S50: Any Pre-1996 E36
Would it be possible to put a 1995 M3 S50 engine in to the engine bay of a 1993-1995 325is?
Nicholas Ellert
via the Internet

Sure. The 1995 S50 will work in any pre-1996 (OBD-I) E36, and six cylinder cars do not require spring and shock conversions to M3 parts, although it is highly advisable, along with M3 brakes.

Shark Injector: Reusable, But Only on the Intended Engine
Is there any way you can reuse the Shark Injector? I bought my Shark Injector for my 1998 323is, but I just got a 1997 3.2-liter M3 engine with ECU and wiring harness to swap in. I want to take the program back into the Shark Injector from my 2.5-liter engine and install on my 3.2l engine. Is any way I can do that?
Cristian Diaz Arata
via the Internet

OK, the Conforti Shark Injector is a reusable tool in that you can download the original or the performance software for the intended vehicle application as many times as you want.

However, what you want to do is different. If I understand you correctly, you have a Conforti Shark Injector for a 1998 323is, and you want to use it on a 1997 M3 engine. Is that correct? The answer is no; it won't work.We spoke with Doug Mahar at Turner Motorsport regarding your question. His reply: "The software load is completely different for the 3.2. I'm afraid there is no way to reset it once it has been used, so in order to "shark" the 3.2, he'd have to buy a new unit. To prevent EWS code theft and Conforti software theft, this was the only way this unit could be designed."

Alaska is Lonely for Bimmers, Too
I have a 1985 325e over 200,000 miles and still running. When I step on the gas my car hesitates a little. I've replaced the distributor cap and rotor, spark plug wires and spark plugs. I've replaced the fuel pressure regulator and hose, the hose going from the valve cover to throttle body, the hose going from the idle air stabilizer to the throttle body, and a couple fuel hoses. I really hope you got some good advice because I really would love to have that power and speed back.
Jahmal Coulson
Ft. Wainwright, AK

The first thing you need to do is buy the Bentley E30 3 Series Service Manual. In it, you will see that among the prime suspects are the reference and speed sensors on this engine. I would elevate that to THE prime suspects. You will need the manual for the diagnostic procedures as they are too long to retype here, and you'll also need it for the drivability trouble tree if I am wrong about the sensor issue. Also, if it's not a sensor problem, verify that the flywheel ring gear teeth are all present and in good condition. I am especially concerned about the speed sensor given your description of the problem. The speed sensor can check out OK and the problem could be the flywheel. See, the speed sensor counts the flywheel teeth to gauge engine speed, which it then sends to the Motronic engine management computer. If there are flywheel teeth damaged or missing, well, that screws up the whole message to the computer. The common result is a miss exactly as you described. Flywheel teeth can be damaged by running the car with a sticking starter drive, which is characterized as a "ching" sound upon starter engagement.

Sigh: Engine Swaps
OK, this is going to be messy: In 1991 BMW came out with a straight six, 3.6 liters, with 311 hp. I bought a 1988 735i. I don't like automatics. I don't like 200 hp. Can the motor swap in? Do the mounts fit the same? Do I have to modify anything? If so, what would you recommend and from which companies?
Ragnar Jubany
via the Internet

The engine you refer to is the S88 M5 engine. My question, which is far less messy than yours, is this: Why would you not simply sell your 1988 735i and buy a 1991 M5 with the engine and gearbox you want already installed by the experts--BMW-- and combined with the brakes and suspension to handle the extra power? You would still have a large four-door sedan, only one that is among the most capable sports sedans in the world, and one that you don't need to build yourself. If the answer is money, then I can guarantee you it will cost less to buy a 1991 M5 than to build one yourself, however interesting a car that may be from an editorial perspective.

While the S88 is theoretically related to the M30 engine in your 1988 735i, very little would bolt up and much fabrication would be involved. In particular, you'd have to fabricate the exhaust system. The M5 used a unique beefed up Getrag gearbox, however you could probably get by using a regular one for the 735i or a 535i or 635CSi. That would be easier, as the E32 7 Series was available with a manual gearbox, so you could order the driveshaft from BMW. Most of the parts you would need in terms of pedal linkages and interior parts would need to come from BMW. In terms of a shop to do the whole deal, I'd recommend Koala Motorsport in Ohio (

You also have the option of converting your 735i to a five-speed manual, and tuning the engine for some more power. I'd recommend a Conforti chip, with your high compression pistons, a Schrick 284 cam combined with a nice three-angle valve job and Extrude Honed exhaust manifolds.

Automatics Issues II
I have an E46 BMW with a ZFHP19 transmission. How would I go about making the transmission stronger, so that it would hold more power without failure or slippage? I would like it to hold 300 lb-ft of torque with no problem.
Yousif Abbas
via the Internet

The best way would be to remove the automatic transmission and replace it with BMW's infinitely more durable manual gearbox. Apart from that, there's really nothing you can do. This transmission already has a big oil cooler, and I don't recommend messing with BMW's proprietary automatic transmission fluid. If you are against converting to a manual gearbox, then my advice is to run it until it breaks and buy a replacement BMW automatic transmission.

Automatics Issues III
I drive a 1999 323i with an automatic transmission. The car came from a BMW dealership with 25,000 miles last December and now I have little more than 30,000 miles. From beginning I noticed a clunk when downshifting down into second and first gears, especially when the engine is warming up and again when I drive in stop and go traffic with engine at full operating temperature.The dealer checked the car, but did not find anything wrong. Please tell me what it could be.
Zibby Piwowarski,
Vancouver, British Columbia

This problem is detailed in BMW Service Information Bulletin 24 09 98 as being caused by excessive axial play between the output shaft and the output flange. A relatively simple repair kit is available, part number 24 21 7 515 388, which includes a new flange and some washers and clips. Tell your dealership to review the bulletin.If you had complained of this problem within the warranty period, the work would have been done for free. However, out of warranty, this is a customer-pay job.

It's All in the Diagnosis
I own a BMW 325i 1995. It's an automatic car I purchased from an elderly lady in mint condition. She never really drove it on the highway (only city driving). Lately, my front wheels shudder if I reach a speed of 120 km or 75 mph. I believe it is the tie rods. When I go over slight curbs or bumps it makes a knocking sound, especially when I go up the ramp of my parkade. I haven't taken it to the shop yet as it drives normally in the city on smoother surfaces. Could it be anything else?
via the Internet

It is impossible to say for sure without having the car for diagnosis, but I can tell you that the overwhelming majority of BMW steering wheel vibrations are caused by simple wheel balancing problems. Bent wheels will certainly do it as well, and sometimes worn out front control arm bushings will lead to a shake. I don't know if your tie rods are worn, but I seriously doubt they are causing the vibration. Time now to bring the car to a professional BMW technician for road testing and diagnosis.

Need a Clutch
I have just purchased a 1988 320is. I love the car, but it needs a clutch. I have found little information on the car other than only around 4,000 of them were made between 1987 and 1991, and they were only sold in Italy and Portugal. It is identical to the 1988 320i in terms of the body, however it has a 2-liter S14 Motorsport engine and the same gearbox as the M3. Will the clutch be the same as the M3 for that year?
Petty Officer Second Class George Lock
United States Navy
Sicily, Italy

Nice find, AO2 Lock. The Italian-specification 320is was a factory homologation so that the 2.0-liter version of the M3's S14 engine could be used in European Touring Car racing. Yes, it uses the same 228mm clutch as the E30 M3. The BMW clutch kit part number is 21 21 2 226 854. The clutch kit includes a clutch disc, pressure plate, and release bearing. Be advised that other parts may be worn in there as well, such as the clutch release fork, release fork pivot, and release fork spring. If the kit contains the new style plastic release bearing, no lubrication is required. If the release bearing has a metallic housing, lubricate the input shaft housing with high-temperature anti-seize compound mixed with a few drops of engine oil. Always lubricate the input shaft splines all contact points of the release fork, pivot, and spring. Also, dot the pressure plate fingers with this anti-seize compound and motor oil mixture. This will give you a happy clutch.

Wheel Quandary
My questions are regarding wheels, in particular the ideal wheels for my recently purchased 1996 328i. I understand that 17 inches is an ideal size for all around aggressive street driving, but I was wondering what an ideal width would be, and also what an ideal tire size would result in a stock diameter. Also, I've been debating with my WRX friend the importance of manufacturing processes and weights. Obviously forged is ideal, but I'm looking at spending about $200 per wheel. I'm wondering how much weight should be considered, and will I notice a difference in street performance between a 16 lb. wheel and a 21 lb. wheel?
via the Internet

First off, understand that if you are running the stock suspension you will want to at least upgrade your shock absorbers before going to larger wheels and tires. I recommend Bilstein HD shocks if you are going to keep the stock coil springs and Bilstein Sport shocks if you're going to install shorter, firmer, aftermarket coil springs. You'll also want to replace the rear shock mounts and gaskets.

Check out the new Meyle design rear shock mounts from Bavarian Autosport ( You should also verify the condition of the rear trailing arm bushings and replace them if necessary with E46 M3 units. Bear in mind these bushings must be loosened while installing new rear springs, and then torqued with the suspension in normal operating position, not full droop, otherwise they will be preloaded and will fail quickly. Also if you lower the car, I recommend E30 M3 aluminum front control arms and E30 M3 offset front control arm bushings. Finally, if the car is lowered, align it to E36 M3 specifications.

Now on to your wheel question. Your correct upgraded tire sizes are 225/50-16, 225/45-17, or 235/40-17. You are good to go with the first two assuming the correct wheel offset, but I cannot promise you that 235/40-17s will fit without clearing the rear quarter panels. For wheel size, 7x16, 7.5x17, or 8x17 in. will be ideal with these tire sizes, repectively. Personally, I'd go with 7x16-in. wheels and 225/50-16 tires, just for economy's sake and a wider choice of less expensive, high-end tires. For an excellent discussion of the affect of wheel weight upon performance and ride, visit this link at Tire Rack's Web site: wheel weights are listed here:

Wheel weight information is not always readily available when we discuss wheels in print--or even when you buy wheels. But your question is a good one; it's a savvy enthusiast who wonders about wheel weight. I'll never forget BMW Car Club of America's Gateway Tech 1993 in St. Louis, when BMW of North America sent two technical representatives to discuss, among other things, the upcoming GPS navigation system. The leader said, "This guy here can answer any question you might have about the new BMW GPS Nav system..." One guy in the back of the room raised his and and said, "How much does it weigh?" If you've never seen a German engineer squirm in front of his boss, it's worth just about any price.

Aiming High
I am wondering if I can put an S54 M3 motor into an E30 3 Series. I know E36 engines can bolt up to the stock E30 gearboxes, and E36 cars carry over engines into the E46. I have a complete wrecked M3 with the SMG transmission to use for parts. I personally do not want the SMG because a computer controls the clutch--personal taste, no arguments please. I know it would be wiser and make more sense to put the S54 into an E36, but I blew all my money on the M3 so all I can afford is an E30. Imagine the potential of a 2,800-lb car with 333 hp.

What will I have to do to perform the conversion? Will I need to custom fabricate mounting locations for the engine? Is the engine ECU a stand-alone system where all I need to do is swap the E46 ECU and all the interior lights, etc., will be working? The differential is still in working order on the M3, so can I swap with the E30 unit? Do I need a custom driveshaft? What kind of performance do you think I can expect? So far, suspension-wise I'm thinking PSS9 coilovers, but I have seen some nice TW racing coilovers for a lot less. I can weld, so chassis strengthening will be up on the list alongside making sure this car stays true to its European roots.

My original plans were to stick an M70 into an E36, but the E36 is gone and I feel there is more potential with the E30 due to its lighter weight. Last but not least, I don't want a big wing on the car but I can't imagine how much lift would occur at speed, especially with this much power. The E30 M3 piano spoiler is already a little much, but increasing the angle (60 degrees max) should perform as good if not better if the wing were as wide, wouldn't it? I intend this car to be a sleeper with the capability of winning bets with NSXs and leaving some non-skilled Ferrari drivers in awe at the track.

Oh, by the way, is there anything wrong with doing a brake stand where the speedo is showing 160 yet the car is stationary other then melting rubber? My friends are doing it a lil' often...
via the Internet

What you propose is certainly possible, but an enormous project. Initially, I would recommend you contact with respect to the engine conversion, because they have already installed several S50/S52 engines in the E30 3 Series. Some fabrication will be required in terms of engine fitment and the exhaust system. There is no way to make an S54 not an OBD-II engine, so you'll most likely have to live with an eternal "check engine" light.

You won't get any arguments here regarding your decision against the SMG, godforsaken infernal contraption that it is. You can use an E30 Getrag 240 five-speed overdrive gearbox (you don't say which E30 you have there), which I believe will bolt to the S54, but Zionsville will know for sure. There's no telling how long this unit will hold up behind an S54, but it's pretty beefy and if you run good synthetic gearbox oil like Red Line MTL it'll probably be OK depending upon service demands. If you use the E30 gearbox then you can keep the driveshaft and the differential. Whether that differential is going to have the ratio you want depends upon the E30 you have, which we don't know. Forget about using the E46 differential; that won't work.

You'll also need the biggest E30 radiator you can install, which would be a 325i radiator. I'd say PSS9s would be a good choice if you want adjustability, but you could save money by simply installing Bilstein Sports and H&R coil springs for a 325i. Make sure you use E30 M3 offset front control arm bushings, and if you buy larger anti-roll bars, I'd recommend every reinforcement sold by Turner Motorsport (

Rear axle lift is clearly an issue on the E30 3 Series, but only above about 110 mph or so. So, if you're building this car to drag race or "sit and spin" like your brake-stand friends, then rear axle lift won't be an issue for you. But if you're gonna pull heavy Rs with the big boys, you're going to need a rear spoiler or wing, no question. Forget about the way it looks and get one that works. The M3 unit is a good choice, but depending upon how fast you want to drive, the BMW M-Technic rear spoiler would work, too, if you can find one. This unit resembles the E28 535is/M5 rear spoiler, and is larger than the 318is/325is rear spoiler, but it's no longer available from BMW last time I checked.I think you can expect performance that will flatten your eyeballs, and the trick will be not flattening the car and yourself in the process. Bear in mind the E46 has a far more advanced suspension than even a performance-modified E30. And there's only so much tire you can fit in the wheel housings of an E30. I know that 215/40-17 or 225/50-15 are the most you'll get under there, and these are the correct sizes for speedometer/odometer integrity.

Last, in my opinion, "brake stands" serve absolutely no purpose other than to wear out drivetrain components and tires, get you beat up or killed by testosterone-enraged onlookers, or arrested by testosterone-enraged police officers.

Stroker Searching
I'm searching for a stroker kit for my 1991 318is. It has 170,000 miles on it. I was wondering if there are any kits that offer high compression plus a bump in displacement, maybe 2.0-liters or more. Here in Pennsylvania there is no emissions testing so I'm OK on that part.
Eric Sierra
Bushkill, PA

The German tuner Hartge once had a 2.1-liter stroker kit for the M42 engine, but today their scientific name is "unobtanius familiarus." They are long gone. You already have pretty high compression at 10.5:1. If your M42 is like most of them, the bottom end is fine even at 170,000 miles, but you need a timing chain, oil pump, and valve job, or at least new lifters, valve guides, and valve guide seals. If you can stomach the expense of a valve job and a set of Schrick cams, that combined with a chip, intake, and exhaust system will yield about 165-170 hp, which is about all you're going to get out of an M42. And it still won't have much low-end torque. Keep the stock cams and do the rest, and you'll wind up with about 150 hp or so. If it's acceleration you're after, your best best is a 4.27 limited-slip differential from a 1991 318i convertible. This is a bolt-in modification, and it won't affect the speedometer/odometer reading due to BMW's electronic speedometer pickup.

Surging Idle Problem:Usually the Idle Control Valve
I did an engine conversion on my 1993 318i sedan with a five-speed manual gearbox. I installed an M50 engine and wiring harness out of a 1992 325i into the car last month. Everything went very smoothly except one thing. It idles at approximately 1,700 to 2,000 rpm and constantly surges. From time to time it will surge up to about 4,000 rpm and stay there until I turn the key off and reset it.I took it into the car doctor and they diagnosed it as having a bad throttle position sensor; the diagnostic machine said that the digital motor electronics had no signal in the idle position from the throttle position sensor. I went home and took the throttle position sensor off my 318i engine (which has the same sensor) and I still have the same symptom. I took a volt/ohm meter and tested the three wires going to the throttle position switch. One wire was a common ground, one read constant 5 volts, one wire read 0 volts in the closed position and moved to 4 volts as I turned the throttle to the full position. I think the fault lies somewhere in the throttle position sensor circuit. This is very frustrating.
Tracy Hahn
Monroe, OR

The throttle position switch test specifications are set forth in the Bentley E36 3 Series Service Manual, which you need to buy if you are going to be working on this car. With the harness connector disconnected and the ignition switch on, terminals 3 and ground should have 5 volts. With the harness connector disconnected and the ignition off, terminals 1 and 3 should have 4k ohms resistance. With the throttle plate rotated from idle to full open throttle position, terminals 1 and 2 at the sensor should vary between 1 and 4k ohms without interruption.

However, I can tell you that 95% of surging or fluctuating idle problems on BMWs result from a faulty idle control valve, not the throttle position sensor.



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