Last-modified: 1 December 1995
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---------------------------------------------------------------------- Frequently Asked Questions for Water Cooled VWs -- Performance -- rec.autos.vw Date: Version: 1 Feb 94 = Creation and copy from tech faqs. 1 Mar 94 = First posting. 1 Apr 94 = Conversion to MsWord for easier maintenance. 1 May 94 = Solo I & II added. Books to read. 1 Jun 94 = Relocating batteries, shock stiffness table, lights, alignment 15 Jun 94 =performance updates, Sound insolation. 1 July 94 =Edits, stressbar updates. 12 Oct 94 = Lots of new stuff. 27 Jan 95 = Partially updated 10 Feb 95 = Finally included Mark's additions. 1 Oct 95 = Updated distribution, formatting. 1 Dec 95 = Updates (note formatting is a bit screwed up) Moderator: Jan Vandenbrande, email@example.com See also the list of contributors at the end. Please feel free to submit any additional info. ------------------------------------------------------------ Copyright Notice (c) -- 1994, 1995: All Rights Reserved The information contained here is collectively copyrighted by the authors. The right to reproduce this is hereby given, provided it is copied intact, with the copyright notice inclusive. However, the authors explicitly prohibit selling this document, any of its parts, or any document which contains parts of this document. ------------------------------------------------------------ Index: ====== GENERAL 1 Q: I want to go faster? Where should I start?1 Q:I'm interested in eventually changing from autox to obtain the SCCA Competition license on and do some amateur weekend racing?. 2 Q:What type of car racing are available (for normal mortals) in the US? 2 Q: What is autocross (Solo II)?2 Q:What are the allowable mods for each auto-x category? 4 Stock: 4 Street Prepared: 4 Prepared: 5 Modified 6 Q: What are the Solo II Classifications for VWs?7 Q:What are the addresses for some of the performance related clubs?7 Q:What are the some of the performance driving schools? 7 Q: Will performance equipment void my car warrantee?8 CHEMICALS 8 Q: What is Rain-X? Does it work?9 Q: Can and should I use synthetic motor oils?9 Q: Is synthetic oil compatible with other oils.10 REFERENCE MATERIAL 10 Q: What are some of the Performance books to Read?10 Q:Whar are some of the Monthly/Quaterly Publications? 11 ENGINE 11 Q: How can I get more power out my VW?11 Q: What's a K&N air filter?15 Q: How do I service a K&N air filter?15 Q: How do I keep my engine cool?15 Q:How can I improve heat transfer/what are alternative coolant fluids? 16 Q:Do "Split Fire" (= name of a plug sold in the US, not a type of plug) plugs live up to their advertised claims? 16 Q: What net wisdom exists on exhaust systems?17 Q:Removing the restrictor in a VW Fox to get more power? 17 Q:What is the relationship between torque and horsepower?17 Q: Should I remove the catalytic converter?18 Q:Are the performance chips interchangeable between cars with similar engines, e.g., VR6 Corrado and Passat? 18 Q: Which performance chips are recommended for VWs?18 ELECTRICAL 18 Q:How can I improve night visibility/increase light output? 18 TRANSMISSION 19 Q: Should I change to a racing clutch?19 Q:What transmission fluid should I use (manual cars)? Why is it important for racing? 20 Q:What's the difference between the normal wheel bearing grease and Spectro SPL grease? 20 BRAKES 21 Q: What and why vented rotors?21 Q: Why cross drilled rotors?21 Q:Is it worthwhile changing my rear drums to disc brakes?21 Q:What are the benefits of steel braided brake lines? 21 Q: What pads should I use?22 TIRES/RIMS/SUSPENSION 22 Q:I want to improve the handling of my VW? Where should I start? 22 Tires & Rims: 22 Q: What are the rim width ranges per tire size?23 Q:What is the largest rim/tire sizes that will fit on my VW? 23 Q:What is rim offset? [D="EinpressTiefe" or "ET" Value] 24 Q:What are the "standard" VW wheel offsets (the amount the rim is offset from the hub)? 24 Q:What is the proper tire inflation for my car for performance driving? 24 Q: What are examples of proper tire inflation autoX?25 Q:How can adjust over/under-steer behavior of my car? 26 Q:My VW lifts its rear inner wheel in sharp turns. Is this normal? 26 Q: Are VW rims interchangeable?26 Q:What are the current preferred tire choices for VWs? 27 Normal 27 Snow 27 Perfomance 27 Race 28 Q:What are "standard" (factory) tire sizes for my VW? 29 Q:How can I tell the characteristics of a tire by just looking at it? 30 Q: Will wider tires help my performance?30 Q: What is a performance alignment?31 Q:What does toe-in, caster and camber mean and how do they affect the car's handling? 31 CAMBER: 31 TOE: 32 CASTER: 33 Q:My stock shocks are shot? What should I use to replace them with?34 Shock valving comparison chart 35 Q:How can I make my car quieter? What kind of sound insulation is available? 39 Q: Is moving my battery to the trunk a good idea? What effect will it have? 40 GENERAL Editor's Foreword: This FAQ is geared at improving the performance of watercooled VWs based on the Golf Chassis (A1- A3: Golf I/Rabbit, Golf II & III, Sciroccos, Corrados, Jettas, Ventos, Convertibles) using predominantly the "1600 type" and larger 4 cylinder engine block and the new VR6 2.8/2.9l engine. Because of this FAQ's origine, most improvements are aimed at the US/Canadian market. The above cars also share many components with Dashers/Passats/Fox's (e.g., engines), though they differ in many other aspects such as suspension and exhaust system. Some of these cars may actually have more in common with Audis. Performance improvements encompasses a wide field of subjects, most commonly referred to in the context of increasing power and improving handling. This FAQ intends to go beyond these traditional meanings and include changes that improve upon the stock design. Performance often is achieved at the expense of something else often not mentioned with the advertised component such as fuel consumption, harsher ride or noise. This FAQ intends to reveal some of these as well. One of the things to keep in mind is cost. In some cases the improvements will costs as much as a new stock part from VW, but in other cases it costs more. Generally you will never recover the cost of these improvements. Unlike real estate, most cars are not investments and therefore the reason for spending money is for pure pleasure. For that reason, you need to make a decision on whether it is worth it to you for the amount of time you want to keep the car. Also, it makes little sense to buy the most expensive suspension system if your engine is about to blow. Fix the rest first perhaps with better components. Not covered in this FAQ are the engines/fuel systems available outside North America such as engines less than 1500 cc and carburetors/mono-throttle FI systems. Another good thing to keep in mind is: "Speed costs money, how fast can you afford to go?" [?] Q:I want to go faster? Where should I start? A:Yourself. Most people only utilizes a small portion of their car's capabilities, and often do not know how the car handles under emergency conditions. Almost EVERYONE can benefit by taking a performance "Driving School" from one of the local clubs (e.g. SCCA, ~1/2 day, inexpensive, fun) or from a performance driving school (e.g. Skip Barber, Bob Bondurant, etc, expensive, fun). It is probably the biggest single improvement you can make and it's a skill you take with you no matter what car you are driving.. In every day driving it may make the difference between an accident and avoiding one! The next question you need to ask yourself is *why* you want to improve your car's performance. Do you want to impress your friends? Do you want to blow away other cars on the street? Do you want to compete, and if so, what type of competition? There are all kinds of car competitions: Autocross, road racing, rally, concours, drag race, and so on? Will you be using this car for your daily commute or will it be purely used for competitions? Depending on what you want to do, you may want to follow a very different path to enhance performance. What runs well on a track may not be acceptable or barely drivable for a street car (clearance, noise, hard ride, rough idle, bent rims, the law...). Additionally, if you want to race in a club, cars are categorized depending on their power and handling, and to what extent they have been modified. For example, it may be better to leave your car stock than to make certain modifications. Most classing structures allow only certain modifications, and if you do somethign else, you'll be bumped to the next category. For instance, in SCCA Solo II autocrossing, Stock- category cars must run on rims that are the same size as the originals. If you go with a wider rim, you will have to run in the Street Prepared category. There, you would also have to lower and stiffen your car and replace your entire intake system in order to be competitive. Q:I'm interested in eventually changing from autox to obtain the SCCA Competition license on and do some amateur weekend racing?. A:I'd suggest starting out in a Stock vehicle. An option, if you really intend to eventually go road racing, is to look for an inexpensive road racing vehicle like a Vee or an IT car, and run it as an autocrosser while learning; then when you're ready for SCCA racing school, you should already have a reliable, well understood vehicle in your possession. Note that it's *very* hard to learn to drive in a formula car. People just starting in driving competitions should be in two-seat sedan-type cars -- things happen more slowly, and they can take passengers and ride as passengers with better drivers. Note that formula racing is also a lot more expensive. Q:What type of car racing are available (for normal mortals) in the US? A:The SCCA defined several types of racing, open to the "public": Solo I is a high speed event, using cars prepared to road racing safety standards; it covers both hill climbs and race track based events. Solo I (and Solo II) are time trials; there is no wheel-to-wheel action involved. Solo II is a moderate speed event; it corresponds roughly to what other clubs call autocross. Safety equipment is not mandated, except for roll bars in heavily prepared convertibles (stock convertibles do not require roll bars in Solo II.) Q:What is autocross (Solo II)? A:Autocrossing (or, Solo II) is timed racing in a controlled situation where the agility of your car, and your ability as a driver, are more important than raw horsepower. Autox courses are usually setup in large parking lots with orange traffic cones. Unless the course is pretty long, only one car is allowed on the course at any time, which means that there's no possibility of going fender-to-fender with another car. Cars are classed, either by the local group (if they're independent) or by the Sports Car Club of America (SCCA), according to their level of vehicle preparation/modification called categories (Stock, Street Prepared, Prepared and Modified, or S, SP, P, M) and by their performance characteristics, i.e., class. There are 9 stock classes from SS (Super Stock) down to H Stock, SP and M go from A-E, but P goes A-F. There is a category that some SCCA regions are using called SM or Street Modified (aka "Open Street Prepared" in some regions). This is for cars that do not fit in Street Prepared but are not competitive for Prepared class. (Note that this is not a nationally recognized class). Stock class was originally intended to be a place for novice autox-ers to "run what they bring", and many local clubs have special classes for novice competitors to compete in for their first year. The current situation for the Stock Category is that it has become BY FAR the most intense competition, followed by either Street Prepared or Modified (depending whether you look nationally or regionally). The two other categories are Prepared (mostly race- prepped production cars) and Modified (open wheel cars and production cars with major engine transplants, etc.). The preparation allowances for Stock Category are somewhat more liberal than one might guess: any front swaybar may be used, and adjustable suspensions are not required to be adjusted to factory specs. As an example, the VW GTI that I run typically is set to 2.25 degrees negative camber and 3/16" toe out at the front. In addition, you need autocross tires to be really competitive, and these tires are worthless for any street use. Most serious competitors in Stock Category buy a second set of wheels and mount autocross tires. The above notwithstanding, autocross competition is amazingly challenging and fun, as long as you understand that you won't be winning any trophies until you get some "seat time". I highly recommend the activity. At the beginning of the autox season most clubs also hold novice driver and performance driving schools which teach you the basics (how to follow the course, how cars are staged on the grid, how to be a course worker, safety issues, etc.). All you need to compete in most places is a street-legal car that can pass a basic safety inspection and a valid drivers license; you're required to wear a helmet (Snell 75 or ANSI Z90.1b (1979) approved) when you race, but there are usually loaner helmets available for you to borrow when you're first getting started. (Note: DOT only approved helmets are not allowed). There's an Internet-based group of autox-ers called "Team.Net" (the "dot" is pronounced) who have a mailing list and an ftp archive to promote discussion of autox- related issues. Send email to "firstname.lastname@example.org" or in case of failure, use email@example.com (the former hoosier address has been decommissioned) to be added to the list. Their URL for WWW access is: http://triumph.cs.utah.edu/team.net.html. They also have a fairly extensive set of archives, pictures and mpeg movies. Also, call the SCCA ((303) 694-7222) and ask for the Solo II contact person in your region; they should provide you this person's phone number, and you can call this person to find out when events are scheduled. Contributors: [Blake Sobiloff <firstname.lastname@example.org>] [email@example.com (Jay Mitchell)] [Jonathan Dove <firstname.lastname@example.org>] [Mark Sirota <email@example.com>] Q:What are the allowable mods for each auto-x category? A:There are four major auto-x categories: Stock, Street Prepared, Prepared and Modified. It is relatively important to avoid spreading the misconception that the four categories are a linear progression -- they're not. Modified is not for "production based cars that have been modified beyond Prepared allowances," because that suggests that Prepared is beyond SP, and Mod is beyond Prepared. It's not so. It's better to think that there are two progressions -- Stock -> SP -> Mod, and Stock -> Prepared -> Mod. I generally phrase the Modified description as "two for production-based cars that only barely resemble their original configuration." Stock: Cars must run "as specified by the manufacturer," with the exception of specific allowances. These allowances include [jay.mitchell]: 1.The use of any front swaybar. 2.Any suspension adjustment IF the manufacturer makes provision for adjustment for non-competition purposes. 3.Any shock absorber that is does not change suspension geometry or alter the range of travel (i.e., must use original mounting position). I [jay.mitchell] use Konis on my A2 VWs, and the Nationals-winning cars have all used Konis as well. 4.An aftermarket steering wheel within 1" total diameter of the stock wheel. Wheels with airbags may not be changed, and cars made after model year 1990 must retain the stock steering wheel. <Note: this allowance may be withdrawn soon>. 5.Road wheels of the stock diameter and width with offset within +/- 1/4" of stock. This means that wheels with 6mm less offset than stock are allowed, resulting in a track width increase of 1/2" For example, it allows wheels with 32mm offset on 8V GTIs and Jettas (stock is 14x6 with 38mm offset), widening the track by a total of 1/2". 6.Any brake lining material. 7.Certain engine "blueprinting" practices, although these are rapidly being phased out. Balancing and blueprinting is only allowed if done by the parts-bin technique; no machining is allowed. Cars model year '92 and newer may not overbore/balance, and all cars starting in 1/1/95 this is not allowed. 8.The use of any DOT-legal "street" tire. The hot setups are BFG COmp T/A R1s or Yokohama A008RSIIs, and these tires are stickier than pure racing rain tires were five years ago! [Jonathan Dove]: 9.Ignition timing must be within factory setting 10Can change the exhaust system behind catalytic converter (if equipped) or exhaust manifold. 11Allows the use of bolt in roll cages. Other than the above modifications, you have to leave your car pretty much as it was manufactured in Stock, including the original driver's seat, body trim (you could add non-aerodynamic appearance bits, but you could NOT remove original trim), battery location and size, except for loose items, such as the jack and spare tire which may be removed. Street Prepared: (Basically the same as stock except for these) Street Prepared was originally intended as an incremental step beyond Stock prep levels. As it now stands, a really competitive Street Prepared car may neither be street legal nor practical for street use. (Note that older cars are subject to less stringent EPA/NHTSA regulations and therefore may be street legal in SP class). Tires must still be DOT legal. In addition to Stock allowances, Street Prepared allows the following: 1.Replacement or modification of stock springs. Replacement springs must be of the same type (coil, leaf, or torsion bar) and in the same location, as original, but the rate, free length, and coil diameter may vary from stock. 2.Installation of camber plates in strut suspensions. 3.Installation of body stressbars. There are strict limitations on the type of "strut brace" that may be installed, but some of the most common ones (Neuspeed front bars, for example) are legal. 4.The use of any wheel size and/or offset. 5 The use of any intake and/or exhaust system that will attach to the original, unmodified engine, i.e., the cylinder head may not be mcahined or drilled to accept a non-stock manifold. 6 The alteration or removal of emission control devices. 7 The installation of any fully padded and upholstered driver and front passenger seat. 8 The installation of any steering wheel. 9 The use of a limited slip differential with the same factory ratio. 10The use of any flywheel, clutch, pressure plate, etc., that will bolt to the stock crankshaft. 11The use of any ignition system, including a crank fire system on a car not originally so equipped. 12Ignition timing can be set outside factory specs. Prepared: Prepared Category is structured around SCCA club racing preparation allowances for Production and GT class race cars. Prepared cars typically have all interior trim removed (not allowed in Stock or Street Prepared), roll cages, full racing suspensions, highly modified engines, and they can run on racing slicks. A list of allowances would be far too long to itemize here, and you have to have both a Solo II rulebook and the General Competition Rules to determine the legality of any particular modification to a car. The following was supplied by Richard Welty: Production is a road race class; although stagnant for many years, there is now change occuring here. the cars in production are substantially different from their road-going cousins. GT: these are generally tube framed cars with sheet metal that resembles a road going car; there are 5 classes, GT- 1 through GT-5. GT-1 contains corvettes, camaros, etc., and GT-5 contains things like Minis, and there are various cars in between. Sports Racers: these are single-seat, closed fendered, special purpose race cars. there are a number of subclasses which are quite different from each other: Sports 2000, C Sports Racer, D Sports Racer, Spec Racer, Shelby Can Am, and so forth... Formula Cars: these are the single seat, open fendered, special purpose race cars. like sports racers, there is a lot of variation in the subclasses, which include: Formula V (based on air cooled VW parts), Formula 440 (based on 2 stroke motors and CVTs), Formula Ford (based on 1600cc Ford motors), Formula Continental (a conglomeration of various older winged Formula cars), and Formula Atlantic. Showroom Stock: a class where theoretically stock vehicles of recent vintage come together and do experiments in clever, difficult to detect cheating. Supposed to be cheap, but ends up being expensive. A more elaborate entry by Bob April: SCCA has a form of racing, Showroom Stock, that purports to be exactly that. Outside of a roll cage, fire extinguisher, and competition harness, the car is supposed to be dead stock. Even the adjustments (such as front wheel camber) must be set to factory specs. Cars must be relatively new. In my experience (some years back) 1/3 of the cars were legal, 1/3 had fudges which probably didn't matter, and 1/3 cheated like hell. You can be in the first third (I was) and still have fun. You get to race at places you see on TV (Watkins Glen, Road America, etc.) I drove the car to the track, put numbers on with contact paper, and had a ball. In circa 50 races I had to get the car towed from the track three times (one head gasket, one destroyed clutch, one large hole in engine block with rod sticking out), although I also once drove an X1/9 back 400 miles in 3rd gear (only), towing a small trailer with race tires and tools. The driver must join SCCA, have a routine physical, and have a helmet, firesuit, and gloves. Figure $1000-$2000 to prepare car and driver. Major maintenance costs are tires and bodywork, and you have some control over the latter. Totalling the car is rare, but it happens. Getting hurt is much rarer, but it happens. You go through two weekends (schools) of supervised practice and mock races and get to enter Regional races. Successfully complete these and you get to enter National races. Once you have the license, you can show up in a Formula Atlantic (the worst safety flaw in the whole thing). Improved Touring: a class where battered, rusty sedans built between 1968 and about 5 years ago come to trade paint. Everybody is sure that the guy who just beat him is cheating, but nobody can afford to post the tear down bond. loads of fun, actually, but watch out for Volvos from Hell. Improved Touring allows for typical (wheels, bars, etc.) mods. The drawback is you'll work on the car, and not learn racing nearly as fast. Be like a Formula 1 driver; just show up and drive. For more info, call SCCA. If you can't find the number, you don't have the proper attitude to do this; it takes a _lot_ of perseverance. American Sedan: Big bore version of Improved Touring; Five liter Mustangs, Camaros, and Firebirds trade paint. Modified Modified Category has five classes, including three intended primarily for open wheel race cars and two for production based cars that have been modified beyond Prepared allowances. In this class, the sky is the limit (almost). In my region, we have two Datsun Z cars with Chevy V8s and a heavily turbocharged Miata in Modified, as well as a fiberglass GT-40 lookalike kit car. Popular Modified cars include Formula Fords, Formula Vees, and F440s. The SCCA publishes the Solo I and II Rules in a book that costs about $10 (for nonmembers, less if you are a member). The rules are updated annually and the current year's rules are available beginning in January. The above descriptions are general and NOT comprehensive: if you are contemplating modifications to your car for Solo competition, I strongly recommend that you buy a rulebook. Happy conehunting! Q:What are the Solo II Classifications for VWs? A:Here is a list of popular VWs, along with their Solo II Classifications: Car Stock Street P Prepared Rabbit/Jetta, GTI (A1) ES DSP EP Rab PU/Fox HS DSP EP 8V Golf/Jetta, GTI(A2) ES DSP EP All 16V ES CSP EP Corrado G60 DS ASP EP Corrado SLC (*) CS ASP EP Passat GL HS DSP EP Passat VR6/GLX GS DSP EP Golf/Jetta III, HS N/A N/A Note: Prepared is currently being massively restructured. (*): Being considered for a reclassification in GS. Q:What are the addresses for some of the performance related clubs? A: Sports Car Club of America, SCCA, (General Car Club), USA, (800) 255 5550 SCCA Cal Club, LA/OC area, Hotline (818) 988-RACE, or contact: Lin Jensen (818) 309 95 91 Renee Angel (909) 947 06 44 Ric (310) 496 39 50 Solo (714) 539 22 57 SCCA Cal Club, San Diego, Hotline (619) 441 13 33 Q:What are the some of the performance driving schools? A:Some testimonials from Ed Priest: If you can afford it go to a Track Time driving school. Cost approx $500 for two days of instruction and time on the racing track of your choice. You learn a lot and it's a hell of a good time. I've gone twice at Road America and am going to take the class at Laguna Saca this fall. The cost is a lot less expensive then Skip Barber and the rest because you drive your own car - which is what I wanted anyway. It's really good to find out what your own car feels like and does at the limit. The good news is that most of the insurance companies cover you during the class for no extra charge. Comment from Mark Sirota: I've taken both TrackTime and the BMW/Skip Barber Advanced Driving School. I took TrackTime in 1988 and Skippy in 1987, so things may have changed -- but I think the two-day BMW/Skippy street-driving school is probably the best for anyone who has never done any real racing. It's currently $975, but worth every penny (and if it saves you from one accident, it paid itself off). Next time you buy a car, spend a thousand less on the car and a thousand more on the driver. And you can take the gains with you into every car you drive. TrackTime and similar schools are great fun, and you can learn things, but not the sort of things that Skippy teaches. Skippy is much more applicable knowledge, and just as much fun. Courses taught on real racetracks are a blast, but are really only relevant if you're gonna be racing on real racetracks. Bondurant Firebird International Raceway Complex P.O.Box 51980 Phoenix, AZ 85076-1980 (602) 796 1111, (800) 842 72 23 Russel Racing School Laguna Seca, 1023 Monterey Hwy, Salinas, CA 93908 (408) 372 72 23, fax (408) 372 0458 Skip Barber Racing School 29 Brook Street Lakeville, CT 06039 (203) 435 1300, fax (203) 435 1321 For additional Schools, see <A HREF="http://www.autosite.com/library/drivschl.htm">Drivi ng Schools</A> Q:Will performance equipment void my car warrantee? A:It depends on what and how extensive you modify your car and whether the parts are street legal. It also depends on what country/province/state you live in. In the USA, car warrantees are not automatically voided if you use street legal (i.e., approved by the applicable authorities such as the EPA/CARB/NHTSA) components. For example, changing to Bilstein shocks will not void your warrantee and neither will changing your muffler to a Leistritz or Gillette muffler. Things become a bit more difficult with engine modifications.Your warranty is not voided unless the dealer can prove that your modification caused whatever damage your car has. However, it may be extremely difficult to convince them to do so, and more than likely they will not want to help you. CHEMICALS Q:What is Rain-X? Does it work? A:It's a chemical to treat your windshield to repell water. Above certain speeds raindrops will just slide off the windshield making wipers almost redundant. This product is used on airplanes. Peoples experiences vary with this product. It works well on some windshields or types of glass (most VWs seem ok) not too well on others (for example, it will have no effect on headlights). In all situations, it will only last for a couple of thousand miles. Some have reported that it forms a haze on the wildshield. I believe that part of the trick to apply this product right is to start with a very clean windshield (use alcohol as a final degreaser), at temperature (18C or 70F) and use extremely clean soft non greasy cotton cloth. Q:Can and should I use synthetic motor oils? A:First have a look at the archive on this. In short, synthetic motor oils are superior in all respect to mineral based oils. However, with regular oils being very good already, the chances of you experiencing engine failure because of oil viscosity breakdown or other factors have become extremely rare under normal driving conditions. Usually, the rest of the cars wears out first. However, under higher stress conditions, synthetic oils will provide you with better protection. Because of their better flow properties, synthetics are also better at start up, better in colder climates, and consequently provide a bit more power (measurable, possibly not noticable). If you use a transverse engined car at a track for speed events (as opposed to a parking lot autocross), you may actually be in a corner long enough to slosh oil clean away from the pickup, with possible bad results (please don't ask how I know: [Editor: I did ask Bob April, and he managed to push a rod through his engine block. The failure was traced to inadequate lubrication due to hard acceleration. He was using Castrol 20W50 in his race prepped Scirocco]). The real solution is to get a baffled oil pan, but synthetic oils will do better than dino oils in this situation. One of the major concerns with synthetic oils is compatibility with seals. The newer cars definitely have seals which are compatible, with older cars this is less certain. In addition, with older cars using conventional oils, false seals will have formed (i.e., gunk) thereby also drying out those seals. Synthetics often have superior detergent qualities and will often wash away those false seals causing leaks through the dried up seals...Sometimes the old seals will recover (because they are exposed to oil again), but sometimes they won't hard. So, it's hard to blame synthetics for causing leaks, it's really the conventional oil that caused the harm. The general recommendation with oil change intervals is to remain with the car's recommendations. With current VWs this is every 7500 miles or 12 000 km. The extra cost of synthetic oils is negligable when compared to other vehicle operating costs including fuel, insurance, maintenance, and depreciation. Mobil claims that the superior engine protection, and reduced strain on batteries and starters, synthetic oils will easily pay for itself over the life of the car. Some additional interesting sites to visit are: <A HREF="vw/FAQs/faq.oil">faq.oil</A> All you wanted to know about oil/synthetics <A HREF="http://www.mobil.com/"> Mobil Oil Corp:</A> Synthetic Oil, FAQs, interesting. <A HREF="http://www.xmission.com/~gastown/amsoil/index.html" > Amsoil:</A> Synthetic Oil Products Q:Is synthetic oil compatible with other oils. A:Here is a blurb from Mobil, and it is probably true for most other synthetic oil. Compatibility With Other Oils Mobil 1 is fully compatible with conventional oils. The two types can be mixed with no adverse effects. Mixing, however, will reduce the level of benefits Mobil 1 offers. Precautions for Mixing with other Sythetic Oils Mobil 1 should not be mixed with any other synthetic products or oil concentrates. The chemistries could be incompatible which can lead to a dangerous reduction in lubricant performance. When switching from other synthetics to Mobil 1, it is recommmended to flush the engine first with a conventional oil prior to the change. REFERENCE MATERIAL Q:What are some of the Performance books to Read? A:A nice contribution by Bob April [Edited]: The following books have been worthwhile to me. In general, they are like a college education; after you have read them you will be better positioned to make specific decisions. "Volkswagen Water-Cooled, Front-Drive Performance Book" Greg Raven, Available from US mailorder houses. Probably the most relevant book for Water Cooled VWs. Note that Greg is on the net at firstname.lastname@example.org "How to Make Your Car Handle", Fred Puhn. Explains the basics of car dynamics, why you would want to make certain modifications, and how to do some of them. [Ed: This book is pretty old by now and except for the "theoretical" issues, which are very good, may be a bit outdated. There is however another book available by the same name but different author that is more up to date. I have seen copies at better bookstores and Auto parts "supermarkets"]. "Performance Handling, How to Make Your Car Handle, Techniques for the 1990s", Don Alexander, Motor Books International, Osceola, Wisconsion, 1991, ISBN # 0-87938-418- 2. This book seems to be a modern day version of the Fred Puhn's book though it lacks some of the "do-it-yourself" procedures (e.g., how to adjust toe, how to make the tool). "Prepare to Win", "Tune to Win", Carroll Smith. After reading "Prepare to Win" you will know how to modify your chassis safely, i.e. why banging bolts in place with a hammer is bad, and what to do instead. You will also learn to recognize quality performance parts as compared to cheap junk. "Tune to Win" is the postgraduate follow up to the Puhn book. I never would have considered accelerating a rear wheel drive car to get out of an oversteer situation. Learn why a Formula V race car has a rear roll bar where your car has an _anti_roll bar. "Racing Engine Preparation", Waddell Wilson and Steve Smith. Old, and discusses V-8s, but there's a lot of stuff you can use. Waddell's engines have been around Daytona many thousands of times. "Bosch Fuel Injection & Engine Management", Charles Probst. Incredibly clear descriptions of the systems, way too conservative in describing and valuing modifications. "Brake Handbook", Fred Puhn. If you're going to do more than change fluid and pads. "Clutch and Flywheel Handbook", Tom Monroe. In conjunction with the shop manual, explained why it was a really bad idea to speed shift my X1/9 at autocrosses. "Secrets of Autocrossing", Watts. "The Front-Wheel Drive High-Performance Advantage", by Jack Doo, ISBN # 0-87938-298-8, Motorbooks International, Osceola, Wisconsion Q:Whar are some of the Monthly/Quaterly Publications? European Car (formerly VW Porsche): Argus Publishers Corp, P.O. Box 452, Mt. Morris, IL 61054-0452 800-877-5602. Most relevant mag in US, [W-VWs & other European cars] Addressed from here on as [EC]. EuroSport Car, McMullen Publishing, 774 S. Placentia Ave, Placentia, CA 92670, (714) 572 22 55, fax (714) 572 1864. New magazine. First issue published in fall 93, published quarterly. A direct, though less refined (busty babes), competitor of [EC]. Many articles are almost direct duplicates of what appeared in [EC]. Addressed from here on as [ESC]. ENGINE Q:How can I get more power out my VW? A:Buy a VW with a VR6 engine :->. It's an FAQ that's worthy of a book, and that's probably where you should start. After you go through this FAQ to give you some general idea, look at the info archive under power upgrades: http://www.cis.ohio- state.edu/hypertext/faq/usenet/autos/vw/performance- faq/faq.html The actual archives are mirrored at a variety of locations also mentioned in that FAQ. Following are a couple of old known modification which are easy & relatively inexpensive that will increase the power of the car. In general, the older the car the more room for improvement. Newer VWs have much less room for easy improvements because many of the components are already near optimal. One easy upgrade path for older VWs is therefore to look at newer VW (Audi) models, see what they did, and see if you can swap parts. For example, older VWs have the restrictive exhaust systems, swapping it with a large diameter one from a newer model (if possible) or using the catalytic converter from an SLC will help. Also be aware when buying "performance" components on their true benefit. Usually the top horse power gain is quoted while ignoring the rest of the power band. Your car may have more top end (high RPMs) while sacrificing power at the low end (low rpms) which is where most street driving occurs. The over all effect may therefore be that the car may actually feel slower off the line, but be great when passing another car. So first decide where you want to improve, then research whether the component in question really achieves that. Also select performance parts that fit in the stock position over those that do not. This is probably more true for suspension components than engine components, but is a good general rule to follow. Parts that deviate too much may require extensive modifications, sacrifice reliability, make more noise, or may even render you car unsafe. In general: Reduce the exhaust backpressure (performance exhaust) Advance the timing (recurved distributors, chips...) Improve breathability (K&N Filter, head port, throttle body, compressor) Add a hotter cam Enlarge the engine (change head, pistons, crank) Replace the engine with a more powerful one. All cars: Use a K&N Filtercharger air filter element (some will argue whether this makes any difference). High end improves a bit. Corrados: 3 HP gain at top. Replacing the airbox with a filter at the end of the air intake also provides some additional gain (but you'll also hear more engine noise...). Use synthetic oils (motor and transmission). 83-84 GTI: Change throttle body with a bigger one (Audi?). [From Peter Tong]: You can get one from a later Audi 5000 of the aerodynamic body style. I think 82 and up. Another good donor car is the '85 Golf or a Golf that had CIS-lambda. You have to seal/cap off a vacuum line coming off it, and in almost all cases transfer your throttle linkage from your '84 TB to the new TB. Just make sure that the newer throttle body has a screw adjustment for the idle speed. You also want to purchase a really small l screw driver/flat bladed screwdriver bit to adjust the idle. On the 84s the idle adjustment was a hex that was easily adjusted on the newer TBs its a screw and with the TB mounted on your current manifold its harder to adjust the idle. You also want to make a plate to put between the new TB and your old manifold to smooth airflow (your 84 manifold has a TB opening that doesn't match the newer larger TB). Buy an old style TB gasket, and a newer style gasket, perhaps new 6mm allen bucket bolts to attach it, and make the plate to go between it. If you want a plate cheap just send me $5 and I'll send you my old one (I had my intake manifold ported and the opening opened up). BTW, even with a Fox manifold the TB is good for at most 4hp. 84-87 Scirocco (US): For the JH 1.8 big-valve engine, use a dual-outlet exhaust manifold from any early car up to '81, get the short TT's downpipe (retain cat) for 10 HP, with a 17% gain at 4200 rpm and more torque Optionally: replace exhaust system from the cat back (US$150) & factory VW g- grind camshaft (Autotech, $99) [From Peter Tong]: What is the difference between the TT downpipe and the downpipe that come stock with the dual outlet manifold on earlier cars? The length is different. The diameter is smaller. The bends are slightly more abrupt in most cases (some aftermarket replacement downpipes aren't mandrel bent even with inner side radius' slightly pinched in). On most of the earlier cars with cats the stock downpipes mated before the cat with a flexpipe. The flexpipe doesn't hurt flow much but is of smaller diameter. Also the position of the collector on the stock pipe is such that it would help at higher rpm - the problem is the dp diameter is too small to support the flow at that rpm (this is from my experience). In the end count on the stock dp getting really restrictive around 115hp. When I first put my 2.0 in and was really revving it - the back pressure from the stock dp combo was so much that I blew a nickel sized hole it it! This happened even though I was running a 2" exhaust and supertrapp rear of the cat. Kind of funny but it happened to seak out the weakest pt on my stock dp and took it out. The stock dps also have two welding methods that I've seen holding the exhaust manifold flange mating surface. One uses a small metal "brace" the other type is just welded to the pipe. The TT downpipe is nicely made and has worked well on my car. It is stiff in many ways compared with the stock system, and tends to transmit more vibrations than the stock system (perhaps due to the stiffness). The collector joins about 2.5-3" before the cat and is 2" diameter pipe. Tubing is mandrel bent and the angles aren't quite as severe as on the stock dp. Also you eliminate the flexpipe with the TT cat dp. What did it do? When I installed it - the midrange really improved. Top end also to a lesser degree. As for actual #s for what they did on my car: 40-60 in 3rd gear: 4.6s before and 4.3 after. This tests 3k to 4.5k rpm. 50-70 in 4th gear: 7.9s before and 7.5 after. 3rd is 1.29 and 4th is .91. r&p is 3.89. So you can see it improved the midrange by about a 6% average. Is it worth $115? It is I guess - it depends on if you are a geek like I am at trying to extract as much out of your engine as possible. As it is that pipe, the G-grind and the TT adjust cam sprocket are the only aftermarket items that were necessary for me to purchase. Oh BTW, fuel economy should improve slightly as well. Fox: Remove exhaust restrictor (see also further and EuroCar: April 89, Aug. 89, Dec. 89, Apr. 90, Aug. 90) 90-92 Passat (4 Cyl): Remove air-intake restrictor, APS Chip, cam. APS chip for automatics that is supposed to do wonders for low end and shift points. Applicable to all cars with 9A engine (inc. 16V GLI). 85-92 8VGolfs/Jettas: The biggest gain can be had with a better down pipe and exhaust system. 85 GTI: Change ignition map by cutting wire #11?? on the ignition control unit and grounding #3 (which was connected to #11). Yields 2 HP additional, torque peak occurring at a lower rpm. See also 85-87 GTI for additional power. 85-87 GTI: KE-Jetronics: Advance ignition idle timing to 12 degrees BTDC or until knock. (factory specifies 6 degrees +/- 2). Gains 5-8 HP with >= 92 octane fuel, very noticeable at the low end. Note, it may reduce the life of your catalytic converter. 90-92 16V GTI/GLI: Motronic Power chips from Autothority & APS. Corrado G60: Stage 1, 2 & 3 chips/packages from APS & Autothority (& others). Stage 1/P-Chip: Chip swap, improves low end by torque 18%, high end by ~5%. Gas consumption improves but you do need Super Unleaded. One of the BEST improvements you can make to this car. Stage 2: Pulley change, chip & fuel pressur regulator (AT) or exhaust (APS) => Power boosted to 180 (APS) or 200 (AT). Noisy, too powerful for the car, APS is more drivable, AT's not CARB approved. Gas consumption near stock. Stage 3: Like Stage 2 but with a cam, affects mostly high end. Remove cold air snorkel (too restrictive) => 1-2 HP gain at the top end (Note: WAY too noisy). Use Neuspeeds Generation 2 system. It solves the airleak created by the idle stabilizer valve. This mod seems to work with most of the above mods as well and provides better boost under all conditions. See also archive G60_Power_Upgrades and Air_Intake_Mods. VR6 2.8l & 2.9l Models (Corrado SLC/VR6, Passat GLX, Golf III, Jetta/Vento): Power chips available from both APS & AutoThority & others. Stage I/P-chip: Gain of 7-10 HP at the top end. Most people reported little or no gain. Some have complained that AT's chip seems to produce knock. Replace throttle body w/o internal air ramp (10% more airflow). This is nothing more than the European progressive TBody. It does make the low end a tad weaker, which, combined with other enhancements will make the car less jumpy. K&N P-Flow filter. APS recommends the above 3 combined to produce the best effect to produce an additional 30 HP. Remove cold air snorkels (too restrictive). Their technical name is "Helmholtz resonator", and it's indeed a sort of muffler. Get a new set of cams, such as those from Schrick. Note: Mostly improves the top end. Use VW Motorsport's Variable Inlet Manifold (VSR). See archive on this. An alleged gain of 30-50 HP at 3000 rpm! Expensive (2300US$), but chances are that certain shops may produce a low cost immitation. Buy a turbo charger kit. VW is about to release a Van called the Sharan that uses a 250Bhp Turbo VR6. Other turbos on the Vr6 have produced around 300Bhp making the car virtually unmanagable. There are a few 3.1 liter conversions available. Not enough info on that as yet. >>>Probably LOTS MORE... Caveat: Most of the above are merely small fixes that do not require replacement of a major engine component such as the cam or the exhaust system, which is usually the next step towards major engine improvements. Those enhancements require a lot more work and expertise to install. Caveat II: Most of the above improvements are approved by the air resource boards for street legal use, but some are not (Stage II, Corrado). Before you install any equipment, make sure that you understand the full implications. Tampering with pollution control equipment is a serious crime, punishable with a 20 000 US$ fine in many states of the USA. Q:What's a K&N air filter? A:It's a washable (i.e., reusable) air filter made out of an oiled cloth like material over a wire mesh matrix. It is supposed to let through more air while retaining the same filtering capabilities. More air => more power, especially at higher rpms. In practice however, the reviews have been mixed. Hot VWs (Dec 92) reported a 3-5 HP gain on the high end in a Jetta. Others have reported no difference or even a slight degrade in performance. My *speculation* is that some cars require to see some vacuum to get the right amount of fuel, kind-a like a choke (e.g., carbureted cars). The same is true with some FI cars (measure vacuum) while other FI cars measure air flow. By the way, a 3-5 HP difference is within normal daily variance of an engine because of external factors such as gas quality, viscosity of the oil, ambient temp, etc. You can probably gain as much from pumping up your tires harder to reduce rolling resistance (but increase wear). From Mark Sirota: I put a used K&N on a flowbench against a couple of other filters, including both types of Bosch filters. The used K&N flowed FAR better than anything else I tried -- by a very significant difference. So the K&N filter alone is definitely an improvement, *if* the air filter is the most restrictive element in the system. I have no idea if that's true. Q:How do I service a K&N air filter? A:You can buy the K&N chemicals (cleaner and reoiler) or you can use a detergent called Formula 409 (used for cleaning kitchens in the US) to save some money (the K&N cleaner is rumored to be the same as Formula 409). You should always use their oil though. Also do not rinse the filter in hot water. It'll shrink the cloth. Q:How do I keep my engine cool? A:Keeping your engine sufficiently cool is needed for all the obvious reasons. VW engines like to run hot, and are more efficient that way. However, under high stress or race conditions, the factory system may not be sufficient. If you run too hot your power is reduced due to engine knock. There are several ways to aleviate this problem: 1) Increase heat transfer with a different cooling fluid or wetting agent. 2) Increase the cooling capicity of your car with a larger radiator. The reason why I do not mention changing the thermostat to a lower temp one is because it merely reduces the average operating temp (which may be too high), but does not change cooling capacity. In extreme conditions the temp rating on the thermostat is not going to matter because they will all be fully open. It is however a good idea to make sure that your thermostat still is capable of opening fully at the intended temp. Q:How can I improve heat transfer/what are alternative coolant fluids? A:Redline sells a "wetting" agent calleed "Water Wetter" as an additive that improves heat transfer. It comes in two forms solid (discontinued), which contains phosphates, and liquid w/o phosphates (OK). People who have used it can't tell any difference under normal driving conditions, but it does make a difference if the problem is that hot spots in the cooling system are causing localized boiling Under normal street use you will not see any change because the thermostat is regulating the temp. It's only when you exceed the capacity of your system and the thermostat is all the way open that the wetting agent will have an effect. The wetting agent is supposed to improve heat transfer by reducing surface tension. This is important near the head where the coolant my locally boil. The little gas bubbles however impede heat transfer, which in turn may lead to knocking and reduced engine performance. Redline claims it can reduce engine temp by as much as 30F (depending on the anti- freeze/water ratio, for a 50% mix it's closer to 10F I think). The performance shop I bought it from said that its good insurance when your car is put under heavy duty (stuck in traffic on a hot day, making a desert run, autocross). Another issue is that glycol raises the boiling point, but reduces heat capacity. With Water Wetter, you can hopefully use less glycol, resulting in higher heat capacity. You want to use as little glycol as you can while still avoiding boiling (and still getting enough lubrication for the water pump, which glycol provides). Note: In certain old high mileage cars, the Water Wetter scavenges out some of the contamination in the cooling passages and holds them in suspension in a way that resembles motor oil. The stuff even "feels" like oil. Redline said this was quite harmless otherwise, and I shouldn't have any problems with hoses or the like. They said because it only happens in a few cars, they didn't feel justified in putting out a warning notice (especially if it causes owners of cars with REAL problems to ignore it). An other alternative described in European Car (Oct 91) is to use !pure! propylene glycol that has a higher boiling point than ethylene glycol though worse heat transfer properties. [email@example.com.HP.com] The higher power VW engines have a problem with pinging under heavy load. This is due to the coolant boiling inside the head. Coolant vapor is a very poor heat conductor. This loss of cooling causes hot spots to form on the combustion chamber side of the head, causing pinging. The propylene glycol does not boil, and this cools the hot spots better. Thus, pinging is avoided, and more power is available if the timing is set to take advantage of the reduced chance for pinging. The cooling system is NOT pressurized, but vented to boil residual moisture away (which lowers the boiling pt). A kit to make the switch is available from: MECA Cooling Company [See the first general FAQ for address] Q:Do "Split Fire" (= name of a plug sold in the US, not a type of plug) plugs live up to their advertised claims? A:Responses from the net & tests by TT indicate: NO, they are actually worse than the recommended Bosch plugs. Note that VW recommends the use of tri- cathode Bosch plugs for some of their cars...so this split-fire idea is rather "old". Apparently it's covered with Techtonics "Amazing Dyno Stories: Parts to get and parts to forget". There's an article in the August 1994 issue of EC where they talk about ignition systems and specialty spark plugs. They interviewed Dr. Chris Jacobs of Jacobs Electronics. The gist of the article is that, cars with weak ignition systems get the most benifit form these special spark plugs (SplitFire, V-groove, etc.) However, the same cars perform better with stock plugs and an improved ignition system than with the specialty plugs and the stock system. [Ed's Note] Most newer VWs have a pretty efficient ignition system, and may see little or no benefit from such plugs or an enhanced ignition system by Jacobs. Q:What net wisdom exists on exhaust systems? A:Gilette: Good balance for street and autocross & last LONG. Some will debate that this is the best (stainless). OEM supplier to VW. Leistritz: Good balance for street and autocross. Galvanized. Note: Stock on VR6 Corrado & Passats. Supertrapps: GREAT for road racing and autocrossing but way too loud for everyday life (rgolen@UMASSD.EDU) OEM: More recent VW mufflers have improved to the point that little can be done to improve them in street legal performance or durability. Also keep in mind that VW now offers lifetime warrantee on their replacement mufflers. Remus makes some interesting exhausts with dual cat- converters. Expensive though. Remus mufflers are easthetically pleasing and almost too nice to use as mufflers. Remus is much better known in Europe than the USA. Borla: Insufficient data. I believe New Dimensions is using their final muffler. Some of the performance shops now also make their own exhaust systems [e.g., EuroSport, Techtonics, AutoTech, Velocity Tuning] with galvanized or steel tubing and 3rd party mufflers such as DynoMax. The quality of these systems vary, and it's therefore hard to make a sweeping generalization. Some work well, others don't. Check around before you buy. Unless you drive a beater and don't really care, avoid Midas. Their mufflers are cheap, reduce power, don't always fit right and they only offer a life time warrantee on the mufflers and not on the tubes (which are expensive, and the first to go). See also the Exhausts archives on this! Q:Removing the restrictor in a VW Fox to get more power? A:There is a steel doughnut going right before the cat. This stock doughnut has a two inch (approx) hole in the center for the exhaust to flow thru. It can be replaced with a doughnut with a 2 1/2" (approx) hole to make the exhaust breathe a bit easier. Not a significant power increase, mind you. [mgm@royko.Chicago.COM (Marty Masters)] Q:What is the relationship between torque and horsepower? A: RPM * torque(ft-lb) HP= ---------------------- 5252 Anyone have the metric version? I am too lazy (i.e., kW = Nm * RPM / 60?) Q:Should I remove the catalytic converter? A:Not if you want to remain street legal, and unlike in the early 70's, these devices have improved so much that the loss because of it has become minimal or in some cases removing the cat will rob you of power. Note: The Catalytic converter on the SLC is rumored to be one of the most free flowing of any VW, and will provide gains when used on a Passat (or possibly other cars). New Dimensions is toying around with this. Note: In the US there is 20 000 US$ fine for messing around with emmissions control equipment. Of course the chance of being caught is rather minimal. Q:Are the performance chips interchangeable between cars with similar engines, e.g., VR6 Corrado and Passat? A:NO, Almost all the chips are different, even within one model. For example, the 92-early 93 US Corrado VR6s have compatible CPUs and chips, but are not compatible with later (distributerless) VR6 Corrados. The chips are ordered by the box number on the CPU and are not interchangable. Q:Which performance chips are recommended for VWs? A:See the archives on Performance improvements as well as the Wired article. The two most trusted companies for VWs chip makers are Neuspeed and AutoThority. There are some disputes that one is better than the other, but it's mostly a matter of compromises. In regards to SuperChips, their reputation has been tainted by some questionable claims and 300$ improvements that had nothing to do with reprogramming the chip (you get back the stock chip!). AMS is also trying to enter this market, but so far there is insufficient data on this. ELECTRICAL Q:How can I improve night visibility/increase light output? A:It all depends what you are starting from, and in what country you live. USA: Sealed beam units till 84 required, "aerodynamic" allowed thereafter but must still conform to a rather pointed spread. 3 DOT nipples for alignment required. Canada: Same as USA. Northern Canada has slightly different regulations. Europe: Sealed beams forbidden. Light is more evenly distributed. Some countries require yellow lights, and different settings for city, highway and hi-beam lights. Beware that whatever you do, you must NOT blind on coming traffic. Some of the suggestions below are actually illegal for street use in the US. However, judging from the large number of misaligned lights in the US, your "illegal" mods will be less blinding than a normal but badly aligned set of lights. However, oncoming traffic may automatically assume that you are blinding when they see more than 2 lights on at once (+ it may be illegal in some states/driving conditions). EuroCar had several articles on lighting in 91/92. To improve visibility, try the following: - Align your headlights. See Bentley or your local code for specs. I usually go a tad higher than the specs w/o blinding. - Change to halogen lights (yes, some of the sealed beam units are not even halogen). - Clean the inside of your non-sealed beam units with some alcohol on some cotton/rag at the end of a wire/stick. (Pretty tricky.) - Add fog lights (very wide, low, but not far reaching). Set up correctly, fog lights DO NOT blind, per definition. Don't buy generic brands, but minimally go for Bosch, Hella, Cibie and others. - Add driving lights (narrow and far reaching). Set up according to specs these DO blind, however, they can often be set up lower so that blinding can be almost entirely eliminated. - Change to one of the non-sealed aftermarket units, which are usually the European style lamps. - Change to the equivalent European "aero-style" units (e.g., A2 Jetta). These are available from a number of sources and have much better beam characteristics than DOT approved lamps provide. Your ability to use them will be a function of the level of detail your state motor vehicle inspection requires. In NJ, they have to come out to pass inspection [Tom Coradeschi]. - Change to poly ellipsoidal, high-energy, "DE" lights. This is the newest technology in lighting technology, more commonly found on newer BMWs (though BMW uses an arc lamp rather than halogen). EuroCar had several articles about these in 91/92. - Change the wattage of your bulbs. This is actually not always a good solution because your lenses may crack because of heat build-up, moisture accumulates faster, wiring may not be able to carry the load, may blind, may not fit in all non-sealed units [According to Andy, you cannot not put higher wattage lightbulbs into the stock North American light lenses. [Unverified...jan] The 70/90 Watt versions of the H4 can be bought at off-road places such as Competition Limited, (313) 464-1458 according to Dilmore. There are also 45/100W versions of the standard 45/65W lamps. Some lamps require you to trim a metal tab that would normally prevent their use for street cars. From Michael R. Kim: I've got 80W low beams on H4, and haven't had any problems being pulled over. I drive with friends a lot, and ever since installing the lights, I've asked them about glare, for fear of getting a ticket. They told me that since I've angled them down just a tad, they don't notice any more glare than a car with factory lighting. Mind you, if you've ever seen one of those Ford F150 trucks, with their lighting, you'd question about proper light angling. I've had the lights in now for almost 5 months now, and have yet to even get a flick of the high beams from someone else for blinding them with 80 W beams. I would definetly recommend upgrading lights, it can do wonders for your driving, but PLEASE double check your alignment and light pattern before going off to test how well they work. TRANSMISSION Q:Should I change to a racing clutch? A:In most cases a racing clutch ("4 puck") is really not needed for street or Autocross uses. VW clutches can easily handle well above stock power. For example, a 16V 210 mm GTi clutch is good to 160 bhp. Furthermore, racing clutches are very harsh (like, all or nothing) and much stiffer to depress. One of the more agreeable changes is to use a stronger pressure plate with a stock clutch disc. Q:What transmission fluid should I use (manual cars)? Why is it important for racing? A:If you use a transverse engined car at a track for speed events (as opposed to a parking lot autocross), you may actually be in a corner long enough to slosh oil clean away from the pickup, with possible bad results (please don't ask how I know). The real solution is to get a baffled oil pan, but synthetic oils will do better than dino oils in this situation. As far as I know, most/all water cooled VW transmissions require gear fluid with an API rating of GL-4 (MIL-2105). The recommended GEAR viscosity hovers around 80W, 75W-80 or 75W-90 Note that 75W-80 GEAR oil is equivalent to 10W30 MOTOR oil, but it is NOT recommended to use motor oil in gear boxes, even though some Japanese cars do so any way (has to do with shear strength). GL-5 oil is made to lubricate gears (like in a differential) and may cause premature wear on brass synchros. NOTE that GL-5 is recommended for the *differential* on some AUTOMATIC VWs and on some manual transmissions. However most VW *Manual* transmissions need GL-4. Check your user manual or VW. Quality of the gear oil makes a HUGE difference in shifting. I have personally tried Castrol (HORRIBLE), SWEPCO (Better), VW gear oil (good, I suspect that they use a synthetic in some cars), and Redline MTL (best so far). Others seem happy with Mobil 1, Synthoil, Spectro, etc. How these oil affect transmission life is unknown to me. Note that MTL is rated 75W80, while their newer product MT90 has a rating of 75W90 which may be closer to the required viscosity of your transmission. VW also sells synthetic transmission oil (at US$20/liter) which is probably one of the best oils to get. Most VW transmissions use somewhere around 2-2.5 liters of oil. Before you drain, make sure you have something to catch the oil (an old jumbo coffee can is perfect). Open the side fill hole first, because you'll have to fill it up to either the fill hole or BEYOND. You'll therefore either have a little bit leak out or 1/2 liter gush out. To drain (the rest), unscrew 17 mm allen plug at the bottom of transmission. To fill, either unscrew speedometer cable or use the fill hole on the side. Some VWs require the level of the oil to be just so that some drips out of the fill hole, others (some A2 Golfs/Jettas) require an additional 1/2 liter on top of that. That's why it's a good idea to catch the old stuff and check the fill hole first. [NOTE: Some VW User's Manuals apparently do recommend GL- 5 in some transmissions, so check first! firstname.lastname@example.org seems to be doing ok with Redline GL-5 after 100kmiles in his car. However, Peter Tong had bad experiences with GL5: he could not get out of 3rd gear with GL-5 oil.] [NOTE: One recent posting by (Paul Keller) blames his transmission failure on MTL, and claims that Redline recommends MT90 only for VWs. At this point it is unclear to me whether MTL is to blame, and whether using MT90 would have made much of a difference. Keep in mind that he is one of two so far which blame Redline out of many who have had no problems so far.] TIP: Glue a small round magnet on the outside of the drain plug. They can be bought cheaply at electronics stores, and it will attract metal particles that may damage the transmission. Older VWs used to have magnetic drain plugs, but VW stopped using them for some reason. Some newer VW trannys now have this magnet BUILT in permanently. Q:What's the difference between the normal wheel bearing grease and Spectro SPL grease? A:The front bearings on VW's tend to take a lot more abuse than on other makes, so many people recommend that you use a synthetic like Spectro to help them last longer. However, there also seems to be some confusion on the matter: most normal drivers are easily able to get 100K mi. out of their front bearings. This is in contrast to racers, who may have to change bearings every race or two, and to GM products, which are supposed to have new bearings every 50K mi. (according to a sign on the wall of a local dealership). [email@example.com (Blake Sobiloff)] BRAKES How to improve/vented/cross drilled/pads Q:What and why vented rotors? A:Braking converts motion into heat. Heat needs to be dissipated. The faster you can dissipate heat the better you can stop, and less fade. Vented rotors essentially have two parallel "discs" with an airspace in between to increase cooling. Many of the Kesley-Hayes non-vented front rotors can be replaced with vented ones and thinner pads without replacing calipers for a slight gain in braking power. Q:Why cross drilled rotors? A:Braking produces gasses, and cross drilling give the gasses a way to escape, thereby increasing contact pressure. In addition, a cross-drilled rotor now has more surface area, and thus cools down more quickly. Personally [Jan] I do not advice cross drilled rotors because of the increased likelihood of cracking. DO NOT CROSS DRILL ROTORS YOURSELF. It's usually done on an NC machine at calculated positions followed by stress relieving. The comments from people on driller rotors are that they improve braking under competitive situations, but only provide a marginal benefit under normal street use. The also feel more uneven when you brake (esp. the slotted ones) and are also noisier (they "humm"). Note that cross drilling is actually banned for certain competitive events, so check before you invest. Cross drilled rotors will also wear out your pads in a big hurry. Another alternative to x-drilling rotors is to buy slotted or grooved rotors and pads. Q:Is it worthwhile changing my rear drums to disc brakes? A:For normal purposes: NO. For racing and other purposes, maybe. Considering the high cost of this swap and considering that only 30% of all braking power comes from the rear, it is usually not worth the effort. Concentrate on the fronts instead. Q:What are the benefits of steel braided brake lines? A:The reports I have received is that it improves brake feel marginally (less expansion of the tubes) but that the steel is also subject to more corrosion. [According to Volney.Spalding@Corp.Sun.COM]: They are not recommended for street use. Reason: Lines are rigid and will not flex with the body as it turns and reacts to road imperfections--rubber hoses will. As a result, the lines can often get pinched and fail. Stainless lines are OK in racing applications because race cars are subject to constant inspections/bleeding/maintenance. If there is an alignment problem it will likely be discovered. Most people probably are not as disciplined in street applications making the this mod impractical. In addition, most steel braided brake lines do not pass the DOT tests and therefore technically illegal for street use. Q:What pads should I use? A:See the discussion in the technical FAQ and also in the archives. It is important to realize that "race pads" (e.g., Ferrodo, to some degree, REPCO Metal Masters) only work well when HOT, and are therefore not well suited for calm city driving. You WILL slide through your first intersection in the morning with these pads. Mintex SilverLine pads are between Repco MMs and stock pads. They may work fine for some cars, but I personally missed the initial bite too much in my G60 that I switched back to stock pads. Note that the company that makes both Repco and Mintex pads is currently in the process of reformulating their compounds. >>>>VOLUNTEERS>>>>????? Needed: diagnosing problems TIRES/RIMS/SUSPENSION Q:I want to improve the handling of my VW? Where should I start? A:Start reading back issues of EuroCar & VW Performance books. It all depends what you want and for what purpose (street, autocross, etc). In general people follow the following road to better handling: Tires and rims, shocks, sway bars,stress bars. Tires & Rims: Probably the biggest single improvement you can make is by changing the stock tires, and in some cases the stock rims. It all depends how much money you have, and what you have as stock equipment. If you want to keep your original rims go to a stickier tire in the stock size. Next step up is a wider tire with a lower aspect ratio for the same rim, e.g., 165/80-13 to 175/70-13 (this is called plus ZERO). To make a more significant impact, you will have to change rims (but be aware that it may put you into a different auto-x category). Generally, you go with larger rims (in diameter) with lower profile tires (=> less tire flex => better handling) and also with wider rims (=> more sidewall rigidity) and wider tires (=> larger contact patch on dry roads, more hydroplaning on wet). Most FWD VWs are made to be run with tires around 1816 mm circumference, so each time you go to another combination you try to stay within a few percent of this circumference so that your gear ratios and speedometer readings remain the same. Odd as it may seem, rims are still measured in inches eventhough the rest of the car is metric... The upgrade gategories are called PLUS ONE, PLUS TWO, PLUS THREE, and so on, with each "+" referring to an additional inch in rim diameter starting from a 13" rim as a base. Note therefore that many of the VWs you buy nowadays are already at +1 or +2. Here's M. Sirota's extensive list of NOMINAL sizes. Actual sizes vary (note the c-program to generate these are in the archives): Spec. Side Radius Diam. Circumf.Revs/Mile Difference wall BASE: 155/80-13 124mm 289mm 578mm 1816mm 886 0.0% 165/80-13 132mm 297mm 594mm 1867mm 862 2.8% PLUS ZERO: 175/70-13 122mm 288mm 575mm 1807mm 891 -0.5% PLUS ONE: 185/60-14 111mm 289mm 578mm 1815mm 887 -0.1% 195/60-14 117mm 295mm 590mm 1852mm 869 2.0% 205/55-14 113mm 291mm 581mm 1826mm 882 0.5% PLUS TWO: 195/50-15 98mm 288mm 576mm 1810mm 889 -0.4% 205/50-15 102mm 293mm 586mm 1841mm 874 1.3% PLUS TWO (MUD AND SNOW): 185/55-15 102mm 292mm 584mm 1836mm 876 1.1% PLUS THREE: 225/40-16 90mm 293mm 586mm 1842mm 874 0.0% Going from 165/80-13 to 205/50-15 will make an enormous difference, however going from 195/50-15 to 205/50-15 will provide less of an improvement (see other FAQ). There are also additional factors to take into account. The first is that tires can only be fitted on rims with certain rim width limts and secondly, there is a limit on how wide a rim AND tire will fit on your car to avoid rubbing with the struts/shocks and fenders. The last is that you also need to get a rim with the correct offset. These are all explained further below: Also keep in mind that for certain competitive events, changing to different size rims may put you in a different class. TIP: [From Roy Kao] DON'T SKIMP OUT ON CHEAPER TIRES!! An investment in good mags is useless with cheap tires. Q:What are the rim width ranges per tire size? A:The rim ranges per tire width (from a Euro-Tire's Catalog) are: TIRE RIM RANGE Diameter 185/55-15 5"-7" 23.03" 195/55-15 5.5-7 23.43 195/50-15 5.5-7 22.72 205/50-15 5.5-7.5 23.11 Q:What is the largest rim/tire sizes that will fit on my VW? A:It depends from model to model. Also, make sure you get the right rim offset or your handling may degrade. Scirocco I: Front: 185 or 195 mm wide depending on model Rear: 205 mm (?) Max Rim: 15"x6" Scirocco II: 205? Rabbit I: 205/60R13 will fit fine. Rabbits/Jetta: Usually > Scirocco! GTI I: 15x7.5 will probably work, depending on what tire you choose. Golf/Jetta II: 215/45R15 fits, at least on a GTI with flared fenders. 15 x 6 & 195/50/15 fit also, =? GTI/GLI GTI/GLI: 215? Corrado: Lower rim limit are 15" rims due to brake calipers, 16x7.5" rims with 205/45/ZR16 work fine. Tire limit =? 225 EuroTire sells 15" steel rims for mounting snow tires. 17" rims may rub and require to roll the fenders Passat: ? A3 Golf (EC March 1994): 7x15, 195/50 or 205/50, 35mm or better, 38 mm offset. 16" rims: 16x7.5 with 205/45-16 or 215/40 R16. 225 are TOO large. 17" rims: too easy to bend a wheel Remember, offset is very important in determining tire fit! >>>ADD MORE ENTRIES>>>This needs to be improved [jan] Q:What is rim offset? [D="EinpressTiefe" or "ET" Value] A:The distance between the rim's center line and its mounting surface. From the picture below it should be obvious why it's important to retain proper offset when you change rims: tire not centered properly affecting drivability (negative roll radius changes), bearing load, rubbing on the struts or wheel arches, etc. Cross sectional view of a rim: Center Plane |\____+____/| |_____.____ | Street Side of Rim . // . // . || Mounting Face . || >--< Rim Offset NOTE: Apparently a deviation of a 5-8 mm does not seem to be too critical according to [Nick Cremelie]. Q:What are the "standard" VW wheel offsets (the amount the rim is offset from the hub)? A:Rim Offset [From TomH, unverified but probably correct] 13x5 45 mm 13x5.5 38 mm 14x6 38 mm (A1 & A2 cars) 14x6 45 mm (A3 cars) NOTE THIS IS UNVERIFIED 15x6 35 mm (BBS 1-piece, # 165 601 026 091) 15x6.5 33 mm (BBS 2-piece) Q:What is the proper tire inflation for my car for performance driving? A:For performance driving things are a bit differently from normal inflation pressures because there the aim is to reduce tire flex and to adjust the over all handling characteristics of the car. Generally, in an autocross or a ralley you will be running at a much higher pressure than normal. One of the old tests is to put chalk marks on the side of the tires, go around the track, and check how much the tire has "rolled" under (i.e., how much flex caused you to scuff the sides of the tires).Note -- this only works on "street" tires. The sidewalls on competition tires are just too stiff for the chalk technique to work -- you need to use a pyrometer and a stopwatch. firstname.lastname@example.org on chalk: Typically speaking, If you run street tires when you autoX, you'll want to bump the pressures up from what you run on the street, but ONLY for the time you're racing. When your racing day is done, bleed the pressures back down to reasonable street pressures, and drive home. Many of the autoXers I've talked with run "race tires" while they race. They bring them in the trunk and take them home in the trunk, and only run them around the track. WHY? because these guys run racing slicks, and everyone knows that racing slicks will KILL you if you run them on the street and it decides to rain. If that is not enough, you can be written a citation by the police for running "bald tires" if you are caught running slicks on the road... Ok, now if you're still not sure how much pressure to run in your street tires, ask someone who has a nice (professional looking) AutoX car out at the track. There's some sort of formula relating to a set of chalk marks that you make on your tires. You "chalk the tires, make a run, and analyze the chalk marks". If you find someone who has raced several times, they'll usually be nice enough to explain it to you, and help you out. Contrary to what some may think, If you are just starting out autoXing, the veterans are actually VERY willing to help you out and explain things like tire pressures and driving techniques. Most of them would talk your head off if you wanted to listen that long, they're a really friendly bunch from what i've found. The rationale for explaining things to novices is to shorten the time that it takes to get the car tweaked, so that you can spend more time behind the wheel perfecting your driving technique. Afterall, it's driving technique that really makes the difference, They'll tell you that. :) email@example.com (Tom Fisk | 751 Siebens | 6-4261): OK...there are several ways to determine proper tire pressures for autocross. The scientific way says that you run a few circuits and then check your tire temperatures. The temperatures should be even from the outside, middle, and inside of the tires. If the tire is warmer in the middle, then your tires are OVER-inflated. Warmer on the edges means that they are UNDER-inflated. If you get variation from one side to the other, than that means you could adjust your camber (+ camber if the inside is warmer than the outside) and visa-versa. For novice drivers in FWD cars on street tires, I would recommend starting at 40-45psi in the front and 30 in the rear. With experience, this will change. Novices need a little more up front than experienced drivers, because they always turn the wheel too far and never unwind properly on the way out of a corner. Q:What are examples of proper tire inflation autoX? A:Examples of pressures used: [Jeffrey M. Mayzurk] On my DSP Scirocco (2300 lb, 55/45 distribution), I usually run with the fronts at around 38 and the rears at 30. This is plenty of pressure to keep the tires from rolling over, and I like theway it handles. firstname.lastname@example.org (James Stulen): I run an 84 Rabbit GTI (ok, it's not quite an SLC) with some mods, on 185/60/14 RE71S tires. I use 36-38 in the front, some time as high as 40 if they're scrubbing to much. I use 26-30 in the back, any more and they just don't 'work', very tail happy then. On the '87 GTI 16V with 218 or 206-compound BFG Comp T/A R1's, I ran 36 in front and 22 in back. Note that these tires require MUCH lower pressure than street tires. Q:How can adjust over/under-steer behavior of my car? A:From Jeffrey M. Mayzurk and also the APS catalog: More Understeer More Oversteer (less oversteer) (less understeer) decrease front tire pressure increase front tire pressure raise rear tire pressure lower rear tire pressure increase front swaybar diameter increase rear swaybar diameter decrease rear swaybar diameter decrease front swaybar diameter less front camber more front camber increase rear camber decrease rear camber increase front shock stiffness increase rear shock stiffness decrease rear shock stiffness decrease front shock stiffness (Note: 'camber' above refers to NEGATIVE camber.) BIG NOTE: The above refers to conventional wisdom. HOWEVER, A1 & A2 VWs benefit tremendously from a thicker front sway bar to reduce understeer due to camber changes. See the section on sway bars! Q:My VW lifts its rear inner wheel in sharp turns. Is this normal? A:Yes, all VWs do this. [From email@example.com (Drbob27)] The reason VWs do this is that VW minimizes front wheel drive understeer by making the rear roll stiffness much greater than the front. When the car rolls, the back is so resistant it picks up the inside rear. The sway bars (actually the ratio of front/rear roll stiffness from bars and springs) CAUSES the wheel to lift. Porsche 911s used to lift the inside front for the same reason (reversed). It's one of the reasons people hold VWs in high esteem as responsive, while similar cars are cited for understeer. I used to race a Scirocco Showroom Stock. In a corner, the mark of a truly excellent turn was to pick up the inside rear smoothly to 4-6 inches and hold it there steadily through the turn. Less competence showed if the wheel bobbed up and down. Q:Are VW rims interchangeable? A:Most VW rims are interchangeable, and it may provide for an inexpensive upgrade from you stock steel rims to used stock alloy rims of an other VW. The exception are the Corrado G60 and the SLC which both require a rim with minimum 15" diameter; the Jetta GLI/GTX 16V (and I think Passat) require a minimum 14" rim, while all other VWs will take 13" rims. VW uses five distinct bolt patterns: 5/180mm (?) Early air-cooled 4/130mmLate air-cooled 5/130mm (?) Transporter/Vanagon 4/100mmWater-cooled 4/100mmWater-cooled 5/100mmVR6 models The standard rims will also work on any car with a 4-bolt 100mm hub. These include Honda (some models), BMW (3- series, 2002...), Omni GLH, Mazda (Miata and possibly others), and any Audi 4-bolts before they switched to 108mm. NOTE: Check OFFSET and center opening before attempting swaps! VW hubs *MUST*BE*HUB-CENTRIC*. This means that the hub opening of the wheel must fit the wheel hub snugly enough to center the wheel. THIS IS IMPORTANT! Note: The center hole of a Honda rim is too small to fit on some VWs, and the offset is wrong. Q:What are the current preferred tire choices for VWs? A:It depends on what you want from a tire...Performance? Long Life? Good dry cornering? Wet weather handling? Snow Tires? Race? There is no single tire that will give you everything. This list is not intended to be an exhaustive list, but just a very brief summary of people's top choices. It's primarily geared towards watercooled FWD VWs, and therefore may not be applicable to other types of cars. For more info see the very lengthy faq.tires.survey. Normal Definition: A mix of city/highway driving on dry & wet roads. Desired Characteristics: All round predictable handling & braking, long life. Bridgestone (?) BFG Comp T/A HR4 M&S (?) Snow Definition: Used for driving on snow and ice covered roads. Nokia Hakkapelitas (sp?) Gislaved Frost Perfomance Definition: Higher speed driving, high cornering forces, summer tires Dry Only: Yokahama A008 Dry & Some Wet: Bridgestone RE 71 Yokohama AVS Intermediary Bridgestone Comp T/A 3 Michelin MXX3, XGT-Z or XGT-V Uniroyal RTT1's (radical tread) Dry & Wet: Dunlop SP8000 (replacement of the D40/M2) - Good but take a while to wear in. Race Definition: Special purpose race tires (i.e., shaven, slicks, mud, ...) Hoosiers BF Goodrich Comp TA R1 - 230 compound Call (800) RACE BFG for info and purchases Bridgestone RE71R or RE71RAZ (autox, call Blackburn Racing, Indianapolis (800)) Yokohama A008 RSII (autox) Toyo Proxy RA-1 (autox, call GT Int'l, West LA) Michelin ?Ralley? (the *only* real mud tire). Comment from Mark Sirota: >From: chrub@CAM.ORG (Chuck Rubin) > Looking for some advice on tires for use in Autocross (Solo2) in Canada > competition on my 1990 Corrado. My friends are using Toyos, Yokos and > RE71s on their CRX's and Civics but noone is racing a Corrado. My car's > got Eibach springs and a Neuspeed rear antisway so it's quite stiff. The short answer is that what works well for one car generally seems to work well for other similar cars -- so since your friends are driving other front-drive sedan-type cars and their tires work well, they'll probably work well on your car too. Out here, the BFGoodrich Comp T/A R1 230-compound seems to be the tire to have. That's officially the road racing compound, but this past week at the National Championships in Salina, I pretty much decided that they're all around better than the 226 autocross compound, except perhaps on very short courses or in very cold weather. The next choices are the BFG 226-compound, or the Yoko A008RSII. I know that the Toyo is a very popular tire in Canada, but almost nobody uses it here. It just can't hold a candle to the BFG and Yoko. I don't know if you get a different version of it, or a different version of the Yoko and BFG, or what... Since your car is stiff, another possibility is the Hoosier Autocrosser. This is a very lightweight bias-ply tire, which has tread and is DOT- approved. However, don't even think about using it on the street. It is not very puncture- resistant (not much better than a slick), and won't last long. It only works well on cars with good camber control (stiffening a production car is often good enough), and with wide wheels. It drives *very* differently, being bias-ply -- you need large slip angles, but the thing really sticks in sweepers. It's not as hot in transients. You need much more steering lock and a lot more faith in the car, as well as the aforementioned stiff suspension and wide wheels. The incredibly light weight also helps in the power department and on bumps. I don't know if it is available in Canada, but you can try calling Tom Reichel at Mid-Atlantic Motorsport in Maryland. Tell him I sent you. His number is +1 410 825 6003. I used to run my GTI and 914 on BFG's, and now run the Formula Ford on Hoosier slicks. Note from Ed: Check with the club's regulations on which tire sizes are acceptable for the group you want to run in. Often, to run in an auto-x stock class you need to stick with the stock sized rims, however you may change the tire sizes. In that case you want to get the widest and least tall tire (i.e., lowest aspect ratio) that fits. If you are allowed to change rims, then you want to get the rims with the smallest diameter but widest that will fit (top speed is not important in auto- x) with the widest and least tall tire. This will lower your center of gravity but also provide you with a better acceleration. Naturally, for street use and other types of racing you other wheel and tire combinations may be needed. It's also a good idea to have your tires shaven a bit to smooth out the outer shoulder. Another issue to consider with racing tires is what rim and tire size to get. For example, in stock auto-x class you have to use the same rim size as OEM, but you are free to use any size tire that will fit. For auto-x it is therefore recommended to get the smallest diameter tire that you can find. This will lower he car and provides a bit more low end torque on the road, tires that heat up quicker, less wheel/tire weight because top speed is not an issue. If you are racing in SP class, then the smallest (but widest rim) that will fit with the appropriate tires is what you want. Q:What are "standard" (factory) tire sizes for my VW? A:The following tires sizes (see the r.a FAQ for how to read these) result in equivalent circumferences and standard on most passenger VWs over the years. The implication of this list is that in principle (if you have clearance!) you could upgrade your tire/rims by traversing this list! The whole aim with changing to different tire sizes is to stay within a reasonable margin of the original tire diameter. 155/80-13 => Rabbit (1975-1978), Golf Diesel, maybe other A2's 165/70-13 => Rabbit (1979-1984) 175/70-13 => Scirocco, Jetta, Rabbit GTI, optional for Rabbit, most non- performance A2s, A3 Golf 185/55-15 => GTX (16V Jettas in Canada), 16V GLI 185/60-14 => Golf GTI, Jetta GLI (85-87) Carat (86-89), Jetta (90-93), Scirocco 16V, A3 Golf 195/60-14 => Quantum, Passat, A3 Golf 205/55-14 => Golf GTI 16V (1987-1989) 195/50-15 => Golf GTI 16V (1990-), Jetta GLI/GTX 16V, Passat GL (1991-) 195/50-15 => Corrado G60 (1991-1992) 205/50-15 => Passat Syncros G60 (1991 +), Canadian 1991 Passat GL 205/50-15 => All VR6 models; 5-bolt rim 215/50-15 => All Passat VR6 models; 5-bolt rim; 6" rim Some non-factory combinations are: 205/60-13 215/45-15 Q:How can I tell the characteristics of a tire by just looking at it? A:This is not easy, but there are a few things you can tell just by looking at the tread pattern. Most performance dry street tires will have lots of big solid blocks (or almost no pattern at all, such as in slick racing tires, see A008). On some tires these blocks vary in size and that's mostly done to reduce certain noise harmonics. Directional or assymetric tires will have block patterns that are oriented in a particular way and that differ accross the width of the tire (typically you can infer the tire's direction of rotation on these tires, e.g., the new line of P0, RE71). To make these tires more drivable on wet roads, you will see one or more big channels along the circumference to funnel water away. Goodyear now markets this technology heavily, though Continental now claims they invented it first. To make tires behave under slippery conditions (snow, mud, ice), they will have small squigly cuts called "brushes" within the major tire blocks. (Obviously I am neglecting the tire compound here that is probably more important than the tread pattern). Most quality tires are made from a "segmented mold" which means that you will see mold marks running accross the width of the tread (othogonal to the direction of rotation). "Budget" tires still use old style molds where you have the whole tire made in two halves and you will see a mold line running along in the center of the tread. The shape of tires also differs between manufacturers. Some tires have a square cross section: |__| (e.g., Pirelli P600) while others use more rounding towards the tread: (__) (e.g., Michelin MXV). It's unclear which is better. The square profiles assumes that the tire is stiff enough not to flex too much, while the rounder profile assume that the tire will roll sideways under hard cornering and therefore these tires often have tread patterns on the side of the tires. It's unclear which works better in reality (though the above two examples should be used for comparison). Q:Will wider tires help my performance? A:There is no straight answer! There are really three main factors that determine handling (disregarding suspension changes for now): 1) Frictional coefficient between the tire and the road, 2) Contact patch size and geometry, 3) Tire sidewall stiffness. If you keep the frictional coefficient constant as well, you have two parameters to play with: Width and Sidewall stiffness. Wider tires will change the contact patch from an oval to a more elongated oval, which generally improves handling, but increases steering effort, and makes the car more prone to aquaplaning (hydroplaning) in wet weather and in snow it never gets to through the snow. In snow conditions the best way to go is small rims (13" for A1 & A2) with a 165- 175/70/13 tire on it. However, another, perhaps more important factor is sidewall stiffness. The stiffer the sidewall, the less the tire will flex sideways which improves turning, transients, steering accuracy Therefore going from a 175/70-13 tire to a "plus 1" 185/60-14 or a "plus 2" 195/50-15 tire will elongate the contact patch, reduce the sidewall height ==> increase side wall stiffness and therefore improve handling. However changing from 185/60 to a 195/60 may or may not do much good: The contact patch is more favorable but the sidewall is also increased in height ==> more flex. Test by VW and EuroCar have shown that an A2 GTI with 185/60 tires handles about the same as one with 205/55. Note that they were using the same car for this test, with the same suspension. (VW sold the A2 GTIs with wider tires purely for looks and customer demand despite the fact that it did little or no good in handling). To make use of wider and lower profile tires the suspension needs to be matched to the tires. But there is more to it as well! Tires, even within one type & size, may have different sidewall stiffness (e.g. HR vs VR), and compound! A softer compound will grip better, but wear faster.. Wider rims make a big difference due to a better lateral support, effectively increasing sidewall stiffness. NEVER use 5.5" on a 185/60 or wider tire; the wider the better, at least within reason. A 7" rim would probably be ideal for a 195/50R15 tire for the street. From Roy Kao: wider tires may make a marginal improvement in transient cornering responses, but how often do you make radicalattitude changes on the street? In summary [From Mark S]: Cost: worse Ride quality: worse Tramlining: worse Handling quickness: better Handling limits: better Safety in standing water, mud, or snow: worse Looks: better (imho) Steering feel: probably worse Braking: can't say for sure Power application: probably worse A lot of the above depend on tire choice, too. Note that choice of tire will have a much much larger effect than changing wheel size on handling. Alignment also has a huge effect, as does tire pressure. Q:What is a performance alignment? A:A performance alignment means a little more toe out than stock, for better turn in, and more negative camber than stock, for obvious reasons. I wouldn't recommend it. Unless you plan to devote you life to autocross (and people do) you will not notice the difference. This will however result in much quicker street tire wear so you will have to balance this with your desire for autocross. I would suggest getting everything else right before you start worrying about alignment though. However, call Eurotire for details about having a car aligned to Andy King's specs. The mild neg. camber does not show up much on the tire edges. Note from Jan: this needs work. A performance set up can be achieved w/o sacrificing tire wear by increasing caster angle, which unfortunately is not adjustable on most VWs. See also the archives on alignment. Q:What does toe-in, caster and camber mean and how do they affect the car's handling? A:This is borrowed from the "alignment" archive: CAMBER: The camber angle is the angle a tire makes with respect to a vertical line. Positive Camber = Tops of tires point outward. If you look at the front of the car you'd see: V FRONTAL VIEW __ ( ) W ( ) __ Tire \ \ ---------- / / Tire -- -- Too much positive camber ==> Tires wear on the OUTside (away from the car) more than the inside. Negative Camber = Tops of tires point inward. Too much negative camber ==> Tires wear on the INside more than the outside. Camber affects directional stability and tire wear. A difference between the front wheel camber settings will cause your car to pull to one side. I also believe it will cause torque steering to become more noticable. It is therefore very important to keep camber for BOTH tires as close as possible. Your car will also perform differently with different camber settings. For street use, follow manufacturer's setting, for race use, use more negative camber (basically so that the inboard tire will be flat on the road in sharp curves). Naturally, more negative camber will wear the insides of the tires quicker. Note however that the terminology used is often very confusing, here is a sample (for either a GTI or Scirocco I think): >--< [Jan] > Camber = -.17 to 0.83 Degrees; which seems to imply that they want > positive camber (tops pointing AWAY). That doesn't sound right. > To make matter worse, in Greg Raven's book, when he talks about > 2.5 Degree Camber he means NEGATIVE camber = / \. Can someone please help > me out with this one? [Mark] Right. Negative camber helps cornering power and turn- in. The reason that they recommend positive camber is to ensure understeer for the "average" driver. At the end of last season, I had settled on about 2.2 degrees negative camber while I was autocrossing. >--< The rear camber is not normally adjustable on most FWD VWs. TOE: Toe = distance between the front of the tires and their rears. Sometimes express by an angle instead. (Negative Toe) = Toe OUT = distance between the front of the tires > rears If you were to look from the TOP: Front ================== Bumper TOP VIEW __ __ Tire \ \ / / Tire -- -- (Positive Toe) = Toe IN = distance between the front of the tires < rears Unlike the camber settings, the individual toe of each front wheel is not as critical (because of the steering mechanism), but the TOTAL toe is (Toe = distance rear - distance front of tire). Usually only one side is adjustable, which then results in the "crooked" steering wheel problem. For the rear wheels the individual toes are however important. If that's off, your car will be driving "side ways". But you do not have to worry about it because the rear toe is not adjustable on most watercooled FWD VWs (w/o special equipment). Too much toe in or toe out will also wear your tires prematurely. The wear pattern is called "feathering" and it will show up as a slanted wear or zig-zag accross the tread of your tires. If you were to take a cross section, you'd see something like (a bit exagerated due to the limitations of this format): _ _ _ _ _ TIRE CROSS SECTION / |_/ |_/ |_/ |_/ | | | Also here things get a bit confusing: >--< [Jan] > The specs for Toe are even more confusing: -15'+10' = - .25 + .17 Degrees. > I assume the "+" is used instead of a "+/-" which results in: > -.25 to -.08 degrees, a slight toe in, which is more what I'd > expect. (Greg Raven however recommends 1/8 inch [yes, inch] of toe OUT). [Mark] Right. So negative is toe-in. The only car on the market today that comes from the factory with toe-out is the Acura NSX. Toe-out also helps turn-in, but does increase tire wear and gives the car a little bump steer. It may also wander a bit on the highway. I was running 1/8" (yes, inch) of toe-out during the autocross season, but now I'm running zero toe. The reason that toe is often given in inches is because it's much easier to measure that way. >--< CASTER: Caster = The angle your wheels pivot about wrt to the vertical when you steer (= the angle of front struts/shocks wrt to the vertical?). __ / \ SHOCK TOWER SIDE VIEW //| // | angle STRUT // O Wheel axle Affects of caster: It keeps the wheels running in a straight line and causes them to straighten when coming out of a turn. Increasing caster also provides better handling w/o the tire wear. Too much caster causes hard steering, too little causes your car to wander. Caster settings do not affect tire wear. If you look at a car from the side, caster is the angle the front strut makes with a vertical line, similar to the fork on a bicycle. When you turn, the axis of rotation of the wheels is not perpendicular to the road, but rather at an angle: V FRONTAL VIEW __ ( ) W ( ) __ TURNING LEFT Tire / / ---------- / / Tire -- -- The result is that the tires "brace" themselves against the cars sideways movement ==> better cornering! I believe this is one of the reasons why a Corrado SLC (with > 3 degrees of caster) feels more stable in a straight line, and corners better than a G60 (with ~1 degree of caster) if you ignore the softer springs and shocks of the SLC. Caster angles are not easily adjustable on most A1-A3 VWs. So if some shop tells you they did, question their abilities... Note: Still under investigation! By changing the subframe to that used on an SLC, a greater caster angle can be achieved. More drastic changes involves moving the shock towers. Q:My stock shocks are shot? What should I use to replace them with? A:VW shocks don't last very long (30-50k miles). The OEM shocks are from Sachs or Boge (note: they merged in 1994) and similar to the Boge ProGas shocks. Stiffer shocks reduce roll, improve handling but also make the ride harsher. Most competition & longer lasting shocks are called "gas shocks" because they contain a gas filled chamber that keeps the shock oil under pressure. This pressurization prevents cavitation and foaming which increase wear and reduces the shock's effectiveness. A compromise to using stuff shocks is to use adjustable shocks. Most popular competition oriented shock brands are: Koni & Bilstein (debatable which is better), then Tokico. From M.SirotA: For non-competition, I'd rank them Bilstein, Sachs, Boge, Koni, KYB (initial quality problems), Tokico (harsh). A note from ND's BBS: We have had many problems with Tokico and do not sell them anymore except for some of the jap cars. They use to have the worst warranty claim problems. They had a plating problem on the shafts and would turn down warranties saying customers were using vise grips on the shafts. Now I have seen what vice grip marks look like as we do get idiots who do that but these were a manufacturer defect. So we decided not to sell them anymore. Koni, Bilstein, Sachs and Boge have very good warranty procedures and we will continue to offer them to our customers. [Note: Tokico Illuminas have reliability problems and a particularly painful failure mode, but the non- adjustables are probably fine.] From M.SirotA: Koni makes three types of shocks: Red, Sport Yellow, and Sport/SS. The Reds are the softest, Yellow are next, and Sport/SS is the stiffest. The "SS" stands for "Showroom Stock", as in the racing category. The Sport/SS shocks are usually also yellow. Bilstein makes at least two: The HD (Heavy Duty), the Sport and the Race. The Sport is the stiffer one. To complicate matters further, not all versions are available for all applications, at least not off the shelf. And old shocks can be revalved, or new custom ones can be made. As with engine modifications that can be measured on a dyno, suspension is very subjective as what may give you the best lap time at the race track may make you VW slower on a bumpy mountain road. That is why each persons driving habits and location of most of their driving is so important to a proper selection. Many VW owners autocross in addition to regular street use and they may sacrafice comfort to have a better handling car on the track. From the AutoTech Catalog: Shock valving comparison chart OE Soft Race Stiff ------------------------------------------------------------ - [<Sach Super/Bilst HD >] [< Tokico HP >] [< Tokico Illumina Adj >] [< Bilstein Sport >] [Bilstein Ralley/Race] [< Bilstein Race >] See also the archives on Suspension_Mods Sway bars: (Anti-roll bars) Reduce side to side roll. Essentially they increase the spring rate when you turn, but leave the bilateral compression rates unchanged. This also means that ride comfort is hardly affected, in general a win-win situation. Most newer VW have sway bars, but aftermarket ones are stiffer (thicker) and are attached better. I personally prefer sway bars that mount in almost stock positions (e.g., VW, Neuspeed, AutoTech) because they are easy to install and do not require major modifications. There are other bars made by H&H and Suspension techniques that have gained some following. The general recommendation is to change the rear sway bar first to reduce oversteer, or to replace them both simultaneously. More recent sentiment has shown that for certain cars (Corrados) the front camber changes are significant and a front roll bar is the first to change rather then the rear. Always keep in mind the racing regulations in this regards. From M. Sirota: Conventional wisdom says that changing the rear swaybar is a good thing. A bigger rear sway bar will move the handling more towards oversteer, and will also help in putting the power down on the way out of corners because it will help to keep the inside front tire planted. However, empirical evidence for A1 & A2 VWs shows that a big front sway bar helps quite a bit, probably because it pays big dividends in limiting camber change. A big rear bar might do the same, but I've never tried it since I only raced my VW in Stock category, and it wasn't legal to change the rear bar. In short, on an A1 or A2 VW in Stock-category autocrossing (where you are not allowed to change the rear bar), run as big a front bar as you can find. [At a later date he adds]: Talk with any SCCA Solo II autocrosser who runs a VW successfully in the Stock category. In Stock, you can play with the front bar but not with the rear -- and the secret is to run as much front bar as you can. Makes the car MUCH MUCH MUCH faster, *and* easier to drive. It's a big win. This is a well-known fact. If you're not racing, or you're racing someplace where it's also okay to change the rear bar, then I can't offer any particular advice -- except that you need more roll stiffness than VW provides, for sure. In an ideal world, we'd only have one sway bar, and it would be in the rear for a FWD car. However, in reality, we almost always use two. If you could change everything else (suspension type, pickup points, spring rates, damper rates, geometry, corner weights, ackerman, roll centers, CG positions, and a host of other things) you might be able to design a perfect system where a rear bar only would be a good thing. However, this is generally impossible on production cars, and so we end up using two bars just so that we can reduce roll without completely screwing up the handling balance. As a side note, I use both bars on my Formula Ford, too. I find that even though I can tune it to be neutral with just one bar, it feels much better in transients with two, probably because the roll *rate* is more similar at both ends that way. And I think they use bars at both ends even on Formula One cars. Stress bars: ------------ Stress bars reduce body flex by connecting either the top of the free standing shock towers, or by connecting the mounting points of the "A" arms. A1 VWs are in most need of a lower front stress bar, while all A1 & A2 VWs could benefit from an upper strut tower stress bar. (A2 cars have a lower subframe and therefore do not need a lower stress bar). The advantage in installation of Neuspeed stress bars over the Autotech bars is that you are not required to work on the inside of the wheel well. The Neuspeed bar comes with these "nutserts" that essentially create a thread in the shock tower to bolt the bar to. The Autotech bars, as I recall, require you to put nuts on the bolts from the inside of the wheel well (they do claim to be a more positive structural connection, which may be so). The Neuspeed bars have also been superb quality and finish-wise. Sporttuning tip from AutoTech: One warning sign of excessive chassis flex is stress cracking of paint around the upper front strut towers. This may eventually lead to the shock towers breaking through. Stressbars can eliviate this problem while also reducing chassis movement. The rear upper shock tower stress bar is mostly for *extreme* race purposes. Robert Collins (see archives) argues that the rear stress bar is pure hype. The effect of a stress bar is somewhat subtle, and does not always translate in a significant performance gains. Both the lower and upper front sway bar have subtle effects. The cars feels "calmer" there seem to be fewer vibration transmitted, and the car feels more confident in turns. Springs: -------- Springs don't normally wear out. However, there are competition oriented springs that usually also lower the car or progressive rate springs that offer a soft ride for normal cruizing but non-linearly stiffen up as they are compressed. One of the things to keep in mind is that springs and shocks need to be matched to some degree or ride may suffer. Most engineers are probably familiar with the equations of a spring and damper combination. Depending on the selected spring and damping constant (and mass) the combination will either be underdamped, overdamped, or oscilatory. Using sport shocks with stock springs may not always be the best combination, nor may sport springs with soft shocks. Sporttuning Tip from AutoTech: Do not cut or heat sag springs to reduce ride height because it does not increase spring rate increasing the chance of bottoming out and the chance to damage the chassis. The problems associated with these modifications include broken strut housings, misalignments, and broken windshield due to body twist. Heat sagging also causes the spring material to become brittle reducing the life of the spring. Stayaway from bargain springs that use substandard wires. **WARNING**: Suspension changes will affect the way your car handles, especially under emergency maneuvers. Therefore it is highly advised that you familiarize yourself with your car before you use it in normal traffic conditions. Taking a performance oriented driving class sponsored by one of the car clubs is therefore highly advised. >>>THIS NEEDS TO BE IMPROVED/REWRITTEN A BIT. SUGGESTIONS? KEEP it short.... BODY/INTERIOR ============= Q:How can I make my car quieter? What kind of sound insulation is available? A:There are a variety of products available on the market that you either glue on the car's inner body panells or spray into cavities. These products are available from either car audio stores, or electronic stores. Do shop around because price varies alot. The effects of this insulation varies with the type of material used and how and where it was installed. Generally, the more you cover up, sometimes even doubling up in certain areas, the greater reduction in noise. It will also improve the sound quality of your car due to the fact you have lowered the resonance frequency. VWs generally produce most of their noise in the engine compartment, followed by the entire exhaust system, the wheel wells (rear), and after that it's probably a toss up whether your doors or your roof makes the most noise. For the more recent models, VW actually did a fairly good job at insulating the car, however, there is always room for improvement. Start with the easily accessible areas that have bare sheet metal, and that sound "tinny" when struck. Most people start by insulating the trunk floor, rear wheel wells, the spare wheel well, and underneath the rear seat. Those areas are right above the muffler or the wheels with little or no insulation. In my Corrado G60, I noticed a reduction in buzzing coming from the rear. The car is now noticeably quieter in the rear versus the front, while previously it was about the same. Some have reported results up to 10 dBa reduction, which is rather significant (a 3dB reduction = 1/2 the noise). If you are more ambitious, go underneath the carpets as well. However, depending on the model of the car, VW probably beat you to it already and it's unclear whether it'll make much of a difference. The next areas to treat are harder. If your car does not have foam underneath the hood, add it. Next try insulating the fire wall, but be aware that that area gets very hot and you need suitable materials for that area. The top is like a bloody drum, in some respects, and anything done here to deaden it or change the harmonic frequency helps. Note that the foam insulation that vw uses deteriorates after a period of time, especially the headliner. Cut the mats to size, than pull of the adhesive cover and stick it to the body panel. Some products require a heat gun (hair dryer works too) to establish a firm bond, or to get the material sufficiently pliable. Some apply additional glue, such as 3M "Spray 99 adhesive" to get a good bond. Probably the most popular product in the USA is that made by Dynamat. Another brand name with a similar product is AccuMat by Scoshe Industries. Both Dynamat and AccuMat sell a variety of types, the thin sheets are generally for covering body panels, the thicker for under carpets, and a high temp mat/foam sheet that can be used in the engine compartment. Other brand names are: Kentamat, Sonex, a foam padding, designed much like the walls of an anechoic chamber, available in various thicknesses and densities, and used to deaden or absorb sound in rooms, chambers, or instrument areas. Dynamat is some kind of asphalt sheet with glue on one side, while AccuMat is made out of latex and the thicker ones out of foam. Some speculate that Dynamat is nothing more than Bitumen roofing paper, and therefore any dense material would work. Some have had limited success with using asphalt roofing material such as "Elastophene Flam" which is an SBF membrane roofing material (it's black, heavy, fireproof, 1/8" thick and relatively cheap) or simple vinyl floor tyles which the AccuMat thin product resembles. I have used the thin sheets from both Dynamat and Accumat, and they both have pros and cons. Accumat costs more, adheres better but does not dampen as well. Dynamat does not adhere well at all (unless you use a heat gun or spray on adhesive), dampen better than Accumat (subjective opinion) but out of the box, Dynamat STINKS majorly. Applying this fresh dynamat over a surface that get hot (i.e., above the exhaust system) will noticeable smell up your car. The problem goes away over time, but it's better if you leave the sheets to bake and air out in the sun for a couple of weeks. Dynamat does sell a low oder version, but that's even more expensive and smaller than their regular sheets. ADVOTECH (CA) sells a product called RattleTrap which is a rubbery goo (it reminded me a bit of Plummers' Putty actually) you squeeze into cavities that buzz. Q: Is moving my battery to the trunk a good idea? What effect will it have? A:[From Jeff Mayzurk]: Yeah, it's a great idea. I did it in my Scirocco and was very pleased with the results. Before you do it, though, take your car to a local truck stop (or any other certified scale) and get the weight for both axles, and then compare afterwards so you can figure out how much of a difference it made. In Greg Raven's "Water-Cooled, Front-Drive Performance Handbook," he discusses the effects of moving the battery on weight distribution. In his example, moving the forty pound battery (mine weighs 38 lbs.) to the rear moves the center of gravity back only 1.9 inches, but has a much larger effect on weight distribution. In my car, I bought a $10 plastic battery box, about 20 feet of 2-ga wire, and a few battery terminals. It's mounted right behind the rear seat on the passenger side, and is grounded at the right-rear seatbelt mount (underneath the cushion). I ran the positive cable along the doorsill, underneath the carpet, through a grommet in the firewall, and to the alternator. After adding additional engine-chassis ground cables, I've had absolutely no problems with charging. Holes can be drilled through the floor of the trunk inside of the battery box between the battery box wall and the battery. Make sure nothing is in the way below the floor of the trunk when you drill the holes. If you know your car extremely well, you will notice the difference right away -- I did. You have the be really sensitive to your car's behavior in transitions, but the difference is there. My car rides better and dives less under braking. Handling feels just slightly more neutral overall, but traction under full throttle in low gears is more of a problem now. (This is the only drawback I can think of, and is definitely something to consider if you have a very light car with a strong motor.) By the way, make sure you have some provision for holding the battery down in the event of a rollover. If your car ever gets upside down (god forbid), you don't want that forty-pound weight flying around in the cockpit. NOTE: Relocating the battery may put you in a different auto-x category! MISCELLANEA >>>> SUGGESTIONS/COMMENTS/CORRECTIONS? send e-mail to above address Contributors (not exhaustive): ------------------------------ Note: Quoted contributions imply possible conflicting pieces of advise with other contributors. See the lists in the other FAQs. mgm@royko.Chicago.COM (Marty Masters) Blake Sobiloff <firstname.lastname@example.org> email@example.com (Jay Mitchell) Jonathan Dove <firstname.lastname@example.org> email@example.com (James Stulen) Jeffrey M. Mayzurk <ELJEFE@utxvms.cc.utexas.edu> firstname.lastname@example.org (Bob April) email@example.com (richard welty) firstname.lastname@example.org (Roy Kao) <email@example.com> (Bob April) Michael R. Kim <firstname.lastname@example.org> email@example.com (Ed Priest) firstname.lastname@example.org (RChambers) email@example.com (Peter Tong) '82 2.0 8v cabby -- highly modified TURBOTIM at ND's BBS (Tim Hildebrand) firstname.lastname@example.org (Matt Lindi) email@example.com (Chad Hewitt) firstname.lastname@example.org (Harry Kimura @ignite) email@example.com (Donald Teed) firstname.lastname@example.org (MBernier) Bryan D. Boyle email@example.com firstname.lastname@example.org (William Hong) Michael R. Kim email@example.com firstname.lastname@example.org (Michael McKay) email@example.com (Wei Soo) chrub@CAM.ORG (Chuck Rubin) firstname.lastname@example.org (Mr Chun Wong) email@example.com (MONSTER16V) MICHAEL H. CHIN" <MHC@ussu.Ciba.Com> firstname.lastname@example.org (H2ONLY) ------------------------------------------------------------ -------- Disclaimer: My employer has nothing to do with this. Use any info in this posting at your OWN risk. This is public information and should not be dissiminated for profit. -- o ___|___ [\\] | Jan Vandenbrande email@example.com __0 /\0/ /-------\ _ | http://alicudi.usc.edu:80/~jan/ \<,_ O \\ (_________) .#/_\_. | If you are still in control, you are (_)/ (_) // [_] [_] |_(_)_| | not going fast enough.