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Project BMW M3 Part 16: A rollbar and more testing

Pablo Mazlumian
Feb 25, 2003
0304_01z+1995_bmw_m3_coupe+front_left Photo 1/7   |   Project BMW M3 Part 16: A rollbar and more testing

The car's performance upgrades are almost finished. I can't fit any bigger brakes, the suspension is more than I can handle and the power is downright scary. Last month I made a few upgrades to help the car run cooler and avoid killing the motor during high-performance driving. This month I'm making an upgrade to avoid killing myself.

0304ec_projm3_03_z Photo 2/7   |   Removal of the carpeting and the front and rear seats make it much easier to install the rollbar.

In case of an ugly mishap, I installed a four-point rollcage. And because someday I might decide to remove it, I opted for a bolt-in system rather than having one permanently welded to the car. Since the car is to remain street-legal, the only option was a four-point bar; as it doesn't hinder getting in and out of the car. Editor Brown directed me to Dougherty Automotive Services, I liked what I saw and ordered its bolt-in rollbar for the E36 Coupe.

0304_02z+1995_bmw_m3_coupe+interior Photo 3/7   |   The DAS sportSYSTEM rollbar is a very nice piece and is probably a good idea for any high-horsepower vehicle that visits racetracks.

DAS started more than 22 years ago servicing Swedish cars, expanded into the German car market and eventually became heavily involved with Porsche club racing, supplying rollcages and other specialized safety equipment to its Porsche customers. And just recently it extended its sportSYSTEM line to BMW cars as well.

The rollbar arrived neatly packaged and unpainted. I made a quick trip to Home Depot and picked up four cans of Rustoleum primer and flat black paint. By the end of the afternoon the bar had two coats of each, and I was satisfied with the look--it was time for the installation.

0304_04z+1995_bmw_m3_coupe+interior Photo 4/7   |   Project BMW M3 Part 16: A rollbar and more testing

Because of his near endless journey in completing his own M3 race car, which includes a 14-point rollcage, I contacted friend Terry Best to help me install the bar. It took two hours of wrestling to get it in place, and it was a near perfect fit, which helps explain why it was so hard to get it in the car.

0304ec_projm3_05_z Photo 5/7   |   BMP Design offers differentials and different gearing. This 2.79:1 rear end was great for launches but not quite what I wanted for the street and road course. But it's great for turbo M3s making anything over 18 psi.

To make the installation as easy as possible, the front seats were removed--that's where all those Doritos ended up! The bottom half of the rear seat had to come off as well, and I plan to keep it off for the time being. It doesn't look very safe to have passengers back there anyway. If your car has fold-down rear seats, the center sections can remain in place to give the car a street look, but the side bolsters will most likely have to be removed.

I haven't yet driven the car on the track with the bar, but already the added stiffness to the rear is apparent. With the go-kart-like snap the car has side to side, I may find myself dialing in some understeer next time I head out to the road course. For added stability, each of the rollbar's four points sandwich the chassis with a plate on the other side.

0304ec_projm3_06_z Photo 6/7   |   evosport installed the 2.79 rear end but later swapped back the stock 3.15 for me. This took place before fitment of the Rogue Engineering diff cover (ec 3/03), which can fit either one.

Ever since the car has had a turbo, traction in second gear has been problematic with more than 13 psi of boost. BMP Design custom built a 2.79:1 rear end with 40% lock-up capabilities from an original BMW differential core to replace my factory 3.15:1. The company also offers other, shorter ratios in between for other high-horsepower applications as well as much shorter than stock for the club racer.

My tuning shop in Huntington Beach, evosport, was hired to work on Project M3 once again. Since it was a rebuilt O.E. unit, the diff was a perfect fit.

0304ec_projm3_07_z Photo 7/7   |   The Valentine V1 radar detector can be used as is, or it can easily be rewired to make use of the concealed display. Either way, the V1 is the best I've ever used. I don't leave home without it.

With the 2.79:1 rear end, first- and second-gear launches are intoxicating. Because the top speed in first and second gear are stretched to around 45 mph and 72 mph, respectively, the car actually ends up making more boost, nearly peaking its dialed-in boost by the middle of second gear. In contrast with a stock differential, peak boost over 13 psi isn't reached until third gear. By the end of third gear, the needle is past 110 mph and says goodbye to 140 mph in fourth. The trade-off? Slower high-speed acceleration.

At boost levels over 15 psi, the difference in rpm isn't felt that much; the engine just feels like it can pull forever. But when I drove the M3 around with its minimum 6 psi of boost, it felt no faster than when I had the normally aspirated cam kit in there (ec 1/02), and it was definitely much slower than the stock 3.15:1 rear end.

What to do? Should I stay with this diff and enjoy just high boost settings? Or should I sacrifice some low-mph grip with the higher boost and the stock diff but enjoy lower boost levels at the same time? As much as I liked the idea of having a 186-mph top speed--for what reason I don't know--with the BMP unit, I didn't want to sacrifice the enjoyment of driving in low boost. I reluctantly had evosport swap the old diff back in.

I wasn't so much concerned with the first and second drag-racing gears as I was with keeping my 50-to-140-mph times as low as possible, since those are the speeds I'd be seeing on most road courses. Plus, over 90 mph in fifth gear was registering at a very quiet 3500 rpm, and I was afraid of getting myself into a lot of trouble on the highway. After all, I had been traveling this whole time without a radar detector.

That soon had to change. To give myself a much more comfortable feeling every time I decided to go crazy and rip 5 mph past the speed limit, I ordered a Valentine One radar detector. Not only does it tell you there's radar out there, the brightly lit arrows point in any of three directions to tell you where it's coming from--the side, in front or from the back.

Valentine reports the V1 is tuned exactly to the frequency bands used by all traffic radar--X-band, K-band and Ka-band, including photo. In my experience so far, every time that Ka-band light goes off with its "BRAP BRAP!" sound to distinguish it from the other bands, it's been a cop. And I have yet to spot a radar-armed cop before this unit has, even in the daytime. I have used other radar detectors before, but none of them have come even remotely close to the performance of this one. I don't leave home without it.

Included in the V1 box was a concealed display module. Like the V1 unit itself, it can be powered up by either the cigarette lighter or the car's battery. This works well for people not wanting the radar detector to be in plain view, or if the cigarette lighter needs to serve some other purpose like charging up a cellular phone. But who needs a radar detector when traffic laws are obeyed at all times? I just bought one for the melodious "BRAP BRAP!" it makes when it spots a cop. It gives me a chance to wave to them and wish them well in their busy day at work catching those degenerate speeders.

Dougherty Automotive Services Inc
(610) 692-6039

BMP Design
(800) 648-7278 or (903) 581-8206

evosport inc.
(714) 731-6040
Order: (888) 520-9971

Valentine Research
(800) 331-3030 or (513) 984-8900

By Pablo Mazlumian
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