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FAQ/Tech Tip Detail:
Performance VW FAQ (Oct '95) |
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| Updated: | Dec 29, 1999 |
| Author: | Jan Vandenbrande |
| Email: | vdb@nwlink.com [email author about this] |
| Answer: |
rec.autos.vw Date: Version:
Moderator: Jan Vandenbrande, jan@ug.eds.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.
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/monothrottle 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-towheel 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 AF. 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 autoxers 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. 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 "autox-request@autox.team.net" or in case of failure, use autox-request@triumph.cs.utah.edu (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 <sobiloff@lap.umd.edu>] [jay.mitchell@the-matrix.com (Jay Mitchell)] [Jonathan Dove <jdove@gsvms2.cc.gasou.edu>] [Mark Sirota <mark@greenwich.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 productionbased 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. (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 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 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:
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:
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 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. 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. 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 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 greg.ihr@kaiwan.com "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 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
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
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
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
Replace throttle body w/o internal air ramp (10% more airflow).
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
Buy a turbo charger kit. VW is about to release a Van called the
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 antifreeze /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. [borowski@hpspkla.spk.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:
[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! blu@cellar.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 |
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