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From: [e-mail] (Jan Vandenbrande)
Newsgroups: rec.autos.makers.vw.watercooled,rec.answers,news.answers
Subject: rec.autos.vw [W] PERFORMANCE, FREQUENTLY ASKED QUESTION (FAQ)
Followup-To: poster
Date: 29 Oct 1996 19:28:53 -0800
Organization: University of Southern California, Los Angeles, CA
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Summary: Watercooled VWs Performance Related Q&As
Xref: senator-bedfellow.mit.edu rec.autos.makers.vw.watercooled:36699 rec.answers:25053 news.answers:85515

Archive-name: autos/vw/performance-faq
Rec-autos-vw-archive-name: performance-faq
Posting-Frequency: bi-monthly
Last-modified: 1 December 1995

----------------------------------------------------------------------

                 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, [e-mail]

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 "[e-mail]" or in case
  of failure, use [e-mail] (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 ([phone]) 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 <[e-mail]>]
  [[e-mail] (Jay Mitchell)]
  [Jonathan Dove <[e-mail]>]
  [Mark Sirota <[e-mail]>]


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, [phone]

  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 [phone]

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
  [phone], (800) 842 72 23

  Russel Racing School
  Laguna Seca,
  1023 Monterey Hwy,
  Salinas, CA 93908
  (408) 372 72 23, fax [phone]

  Skip Barber Racing School
  29 Brook Street
  Lakeville, CT 06039
  [phone], fax [phone]

  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 [e-mail]

"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 [phone].
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. [[e-mail]] 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 ([e-mail])

  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. [[e-mail] (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, [phone] 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! [e-mail]
  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). [[e-mail] (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 [e-mail]]: 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.

  [e-mail] 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. :)

  [e-mail] (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.

  [e-mail] (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 [e-mail] (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: [e-mail] (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 Dynamatü. Another brand name with a similar product is
  AccuMatü 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.
[e-mail] (Marty Masters)
Blake Sobiloff <[e-mail]>
[e-mail] (Jay Mitchell)
Jonathan Dove <[e-mail]>
[e-mail] (James Stulen)
Jeffrey M. Mayzurk <[e-mail]>
[e-mail] (Bob April)
[e-mail] (richard welty)
[e-mail] (Roy Kao)
<[e-mail]> (Bob April)
Michael R. Kim <[e-mail]>
[e-mail] (Ed Priest)
[e-mail] (RChambers)
[e-mail] (Peter Tong) '82 2.0 8v cabby --
highly modified
TURBOTIM at ND's BBS (Tim Hildebrand)
[e-mail] (Matt Lindi)
[e-mail] (Chad Hewitt)
[e-mail] (Harry Kimura @ignite)
[e-mail] (Donald Teed)
[e-mail] (MBernier)
Bryan D. Boyle  [e-mail]
[e-mail] (William Hong)
Michael R. Kim  [e-mail]
[e-mail] (Michael McKay)
[e-mail] (Wei Soo)
[e-mail] (Chuck Rubin)
[e-mail] (Mr Chun Wong)
[e-mail] (MONSTER16V)
MICHAEL H. CHIN" <[e-mail]>
[e-mail] (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 [e-mail]
   __0    /\0/   /-------\      _    | http://alicudi.usc.edu:80/~jan/
   \<,_  O  \\  (_________)  .#/_\_. | If you are still in control, you are
(_)/ (_)    //  [_]     [_]  |_(_)_| | not going fast enough.