Here's where we act like we know something technical about cars. Feel free to ask us about your technical troubles. Write us at firstname.lastname@example.org or Super Street c/o Tech Support, 831 S. Douglas St. El Segundo, CA 90245. Feel free to include a picture of your project or tech problem.
I Thought The Map Was In The Glovebox?
Q I am a first-time subscriber and really enjoy your awesome mag and how you cover all types and styles of cars. My question is what is the difference between a MAP system and a MAF? I currently own a '98 Eagle Talon TSI and I know it has a MAF, but I had someone tell me that they go hand-in-hand and you can't have one without the other. Yet, I read in one of your issues that a MAP system is unable to compensate for modifications that increase air flow so doesn't it defeat the purpose of a MAF?
A Somehow all the information you have obtained is exactly backwards. Manifold Absolute Pressure (MAP) and Mass Air Flow (MAF) sensors are similar in that they both monitor air flow, but they go about gathering this information in different ways, and you either have one or the other, not both. A MAF system is more common in Japanese cars and measures the amount of air that flows across the sensor which works great for stock vehicles but cars running a turbo setup w/a blow-off valve that purges into the atmosphere are often confused by the quick loss of airflow after the sensor. A MAP sensor calculates the pressure/vacuum inside an intake manifold or plenum making it less susceptible to failing under differing barometric pressures or boost levels.
Knowledge Is Horsepower
Q I am an avid fan of your magazine and I would like to thank you for attracting me to the import scene. In your last issue, you guys did an article on the kiwi green S13 with an SR20DET. I enjoyed it a lot because I have been interested in swapping out the KA sitting in my S14 for an SR or maybe even an RB. The problem is, I would like to do it myself for the learning experience but I also don't want to bite off more than I can chew. I know about the DIY DVD from Syko Performance but I want to actually know why I'm doing some of the steps required. Is there any website or book I can buy so that when I look under the hood of my precious 240, I know exactly where everything is and what's it doing? I know some basics like the intake, intercooler, turbo, etc. but I feel like I need more.
A One of the most convenient things about the immensely popular 240SX is how easy it is to find information about them. Two websites you should definitely sign up for if you haven't already are nicoclub.com and zilvia.net as they are the larger forums for your vehicle. If you really want to know what everything under the hood does you should find the factory service manual (FSM) for your car and purchase one. You might also be able to find PDF versions online at one of the sites listed above (hint hint).
Q Hey I have a 1987 Porsche 944 Turbo. I know you guys specialize in JDM, but I was hoping you guys could help me out. I've always wondered if it was possible to set-up a Porsche to drift!? Basically, I know that a proper LSD and basic suspension are the absolute minimum to get going sideways right? Well here's my dilemma, no one sells a proper 2-way LSD for my car! Or at the very least I can't find one. I know of a Quaife unit, but that one is a viscous design. Next to that, it's impossible to find an affordable coilover set. I'm trying to find an entry-level coilovers with adjustable damping, yet the only one I've found are the KW Variant 3. I would love to get those, but alas they are out way of my budget. Besides that, I've gone through and replaced the bushings, engine mounts, transmission mount, thicker sway bars, etc. just the coilovers and LSD are the last pieces before I feel confident about taking my ride out to the drift events. Thanks, you guys make the best mag out there!
A We can't remember the last time we went to a track event and didn't see a 944 so there is certainly hope for your nimble chassis. Being front-engine RWD it should be nicely-suited to drifting. As far as LSDs are concerned you have a few budget options to get you started. On the free level, you could weld your differential which would make the car a pain to drive on the streets but easy to drift even with low power. For less than $500, you could get a unit from Phantom Grip that will convert your diff into a LSD or you could look for a factory LSD unit from a Turbo S model. As for the suspension, while the KW units are amazing and definitely worth the price, we understand not everyone has the budget for them. Keep in mind there are many good suspensions that aren't coilovers and not all coilovers are necessarily good. We'd recommend taking a look at Bilstein and Koni basic units as these will offer excellent performance at a fraction of the price.
Cracking The Code
Q I would like to know if you can help me with something that's been on my mind for a while. I know it's a stupid question but that's me! The question is about the VIN number. I would like to know what the characters mean. I know that the 4th, 5th and 6th are the chassis code but I don't know what the rest are. For example can you explain my VIN? JH4DB2XXXNSXXXXXX (censored by SS). Thank you for a great magazine and thanks to all your staff for all the hard work!
A There is no such thing as a stupid question and this is probably one of the biggest FAQs in the car world. Here's a basic breakdown of what the numbers are representing. The first character is the country of manufacture, in your case Japan. The second character is the make of the vehicle, yours being H for Honda (Acura doesn't have their own). The third character indicates the manufacturing division. Characters 4-8 indicate specific vehicle features like chassis, engine, model etc. What we can tell from "DB2" in your VIN is that your vehicle is an Integra (D) sedan (B) GS-R w/B17 engine (2). The 9th character is probably the strangest part of the VIN and is referred to as the check character. Its purpose is to validate a VIN number using one of Einstein's theories and lots of math (no we aren't making this stuff up, google it). The 10th character indicates the year, yours being 1992 (N). The 11th character is the production plant and the remaining characters are your vehicle's unique serial number.
Bored Of Honing
Q I have a H22A4 and I'm going to put new OEM Type-S pistons in it. I was wondering when putting new pistons in do you always have to bore and hone the walls? Here in Tulsa, Oklahoma there's no one that plays with the firm H22 walls. My walls aren't that bad, I cant feel the scratches with my fingernails so what do you recommend? Thanks and keep up the good work Super Street!
A Boring out the block is only necessary if there is damage to the walls or you want to increase the displacement of the engine. However you will absolutely need a simple re-hone to seat the rings. If the walls are smooth, as you've stated they are, the new rings won't seal and the engine won't compress properly.