R. Miller

I'm going to start auto-x next semester. Although I've as yet not decided on a porsche or rice burner I believe adjustments allowed in Solo II Showroom Stock Class are essentially similar. Can anybody explain or point me towards literature that explains such things as...

Camber/Caster/Toe-in/out
Tire Pressures
Spring Rates (poundage)
Weight Reduction
Brakes/Tire/Wheel Sizes
Timing Adjustment
etc...

I realise there are hundreds of things that can be adjusted under the showroom class rules but any help for a future ***-kicker (actually *** kisser to those that are good at the events I attend!)

Adam Richman

"This class includes mass produced vehicles able to be used for normal street driving. Stock Category cars must compete in their showroom configuration with only minor modifications allowed such as aftermarket shocks, wheels, and tires. Other minor modifications are allowed as well, so please refer to the Solo Rules for details."

From http://www.scca.org/amateur/solo2/classes/index.html

To my (very limited) knowledge, there is very little you can do to the suspension of the car in the Stock Classes (with the exception of trunk kits for some imports).

Personally, I would think of getting a car that would be competetive in Solo I and Solo II stuff even if you don't plan on visiting big tracks anytime soon. Cars I would buy for this purpose (who knows, if my maintenance costs keep piling up, I still might). . . 94-95 Integra GS-R, BMW 325i, Nissan Sentra SE-R (1st Gen - this is what I was looking for and eventually gave up opting for the P-car).

Adam Richman

This looks promising as well: http://www.moutons.org/sccasolo/

Excerpt:

• Anything available on the exact model and year of your car as standard or optional equipment, as installed on the factory assembly line (nothing available only dealer-installed is allowed), plus
• Standard OEM identical replacement parts
• Accessories, gauges, appearance, comfort, and convenience items (not replacement driver's seat, though) that basically don't help
• Added roll bar or roll cage to spec (not required, though)
• Driver harness (no cutting seats to install, though)
• Trailer hitch and/or tow bar mountings
• Any wheel of diameter and width identical to a stock or factory optional wheel, offset within +- 0.25 inch
• Most street legal tires that will fit the mounted wheels and stock bodywork
• Any shock absorber of the same type and mounting as original; no change to standard spring mountings is allowed; suspension geometry may not be altered; gas or hydraulic shocks are permitted
• Any brake linings; pre-1992 cars may use solid/braided metal brake lines.
• Any front anti-roll bar (no change to stock/optional rear anti-roll bar, if present)
• Manufacturer specified ignition settings only
• Any replacement air filter element (or removal of air filter element); no plumbing changes, however
• Engine bored no more than .020"; no balancing or porting/polishing of head
• Replacement of any part of the exhaust system past the catalytic converter (if quiet)
• Any oil filter
• Added clutch scattershield

Seattle944t

If your going to run in stock class you pretty much can't change most of these things. And when your just starting out its really better to not worry about these things. It is far better to focus on you as a driver than on how good your car can be. If you have not picked a car yet, I would suggest you do one of two things; 1) Buy a car that you WANT to drive. If you want to go out and have fun this is the ticket. Chances are that there are several other drivers that are going to be much better than you when you start any the car is not really going to help or hurt you, unless you get a yugo . 2) Go to the events locally and see what cars are consistently winning. Every class usually has a few cars that are "THE" cars to have. Then after doing your research buy one. Expect to be substantially behind the pace set by other drivers though. Not to disuade you or anything, but its going to be tough to get to the level of the other drivers that have been doing this for years. It takes a lot of seat time to pick up the skills. Really you should use your first events as a learning opportunity. Make good use of any novice training classes or instructors that are offered. These things will make a much bigger differance in your times than if your car has the proper set-up. Have fun and get to learn how you and your car respond.
But I can answer a few of these.
Camber is the orentation of the wheel to the vertical axis. Positive camber would mean the top of the wheel would be leaning away from the car. Negative camber is where the tops of the wheels lean in twords the car. Negative camber is good to a certain point to aid in cornering. It allows the tires to get a better contact patch when the cars weight transfers. But most cars have very little adjustment available from the factory. More camber can not be added in stock classes beyond what is factory allowed.

Caster, I think, is the orentation of the shock mounting point to a vertical access. Positive ot negative would effect the relation of the shock tower to front or rear of the car from the lower mounting point. This effects things such as squat and dive under acceleration and braking. I don't think any street cars offer adjustment for this.

Tire pressures you usually want to run higher than normal in autocrossing, it helps stiffen the sidewalls and reduce the amount of 'roll over' of the tire. This is when the lateral forces cause the tire to roll off the tread to the point where the sidewall is now touching the pavement. VERY BAD. Starting off a good check is to use shoe polish on a few spots on the tire to learn how much roll over is taking place. Just put a few spots on the edge of the tread and down to the start of the sidewall. As you make your runs the shoe polish gets rubbed off and you can tell if your driving on your sidewalls. If that is happening then you want to increase your pressures. Also if there are other people running the same car and wheel size you can ask them for suggestions. Even better if they are using the same tires since tires very greatly by brand/model.

Spring rates are measured in pounds and indicate how much force is required to compress the spring. Have to use factory springs for stock, no changes. Most aftermarket lowering/performance and some factory springs are 'progressive' meaning that the spring rate gets higher as the spring is compressed. This allows a softer ride for day-to-day driving but gets more agressive spring rates as the car is pushed harder.
Weight reduction is just getting rid of things that aren't essential. For stock that pretty much is limited to spare tire, jack, tool kits, etc. Less weight helps in every aspect of car performance. I have heard that a racers rule of thumb is that for every 10 pounds reduced is equal to picking up one horsepower.
Brakes - Can only change pads and I think brake lines for stock. Bigger brakes can help you stop, but it's more the tires job. Big strong brakes don't help if you have tiny tires or bad compound rubber - it will just lock them up sooner. Bigger brakes also act as a larger heat sink to reduce brake fade. This really doesn't happen during autocrossing, usually only on tracks.
Tires/Wheels - Tires are free for stock, only must be DOT approved, but Wheels are fixed at factory sizes. You can't change the wheel size, but you can change tire sizes similar to 'plus sizing'. For instance a 205/55/16 can be replaced by a 225/50/16. Or a 225/50/16 could be changed to 245/45/16.

Timing adjustment is either ignition timing, or cam timing. Stock you can adjust ignition timing within factory limits, cam timing is not allowed. Careful turning with ignition and cam timing can help your car produce more horsepower, but could take a lot of dyno tuning to discover.

SHRKBIT

I just went through the 2001 SIIR rulebook yesterday (but not the updates) looking for changes I might make to run in stock class next year. The items of interest to me are:

- stock springs, period (ugh)
- shocks allowed up to 2 external adjustments
- add, substitute or remove front sway bar
- sticky tires
- exhaust mods downstream of headers/cat

However, this is my first full autocross season and I'm running it on street tires with minimal mods to the car. Best thing for us beginners is to learn how to drive the car better. There is *a lot* to learn the first year, even on street tires. So, find the appropriate novice or "street tire" class and have at it. Sure, go buy a car that can be made competitive, but understand that rule or class changes the following year may make it less so. Learn to drive better this time 'round.

R. Miller

I was under the impression that stock class is under SoloII. I had also thought that the 951 was an excellent subject for auto-x? Have I understood wrong? What are good street tires for auto-x? Does the PCA have similar rules/classes for their events? God forbid are there any other good cars for auto-x within the $10K price range?

SHRKBIT

Er, hmmm. Various clubs use different classing systems. This year I've seen 4 classing systems. Solo II is an SCCA term--hence my mention above to the Solo II Rulebook (SIIR). I'm not very familiar with "Showroom Stock Class." SCCA membership information and whatnot can be found at www.scca.org.

See also www.sccaforums.com.

I dunno about 951s. There is probably some concern about whether you can even get into the boost on tight courses, though I see quite a number of turbo cars at SCCA events, usually the ecplise/talon type.

Folks I know have had good experience with Bridgestone S-02s and RE-730s, as well as BFG g-Force T/A KDs. Some of these are a little pricey. I'm running S-02 PPs and am quite pleased.

I've seen different PCA regions run different class rules. Neither used SCCA class rules.

Hey, I'm still getting beaten by Neons and Miatas. No need to spend big bucks on an autocross car if you're just starting out.

You might spectate at events in your area to find out what people are driving, tire preferences, etc.

SSilver

Our Zone PCA runs really succesful Autocrosses. Last weekend we had upwards of 140 entrants.

After several years of autocrossing, I can say that the 928, though a wonderful car, is very poor out on the autocross crosses. Too heavy, not the best in braking.

You're gonna be classed in scca with a lot of cars that can beat you. Check out www.pca-ggr.org and the rule book we use.

R. Miller

Perhaps I made myself unclear, I do not plan to purchase a car soley for auto-x. Rather auto-x is purely a side thing for me. I just feel if I am to get another car I might as well get one that is suitable for auto-x vs an old 'vette right? I do not believe for one second I will be good my first years of auto-x, I just want to do it right see?

Adam Richman

FWIW, my comments in favor of the Integra GS-R/Sentra SE-R/BMW 325i were assuming you were looking for a very practical daily driver (esp. the Acura and Nissan) that you could eventually be rather competetive in SoloII. Basically, I would be looking for a bulletproof motor (I am comparing a 100,000 mi. tune up interval vs. 45,000 mi. preventative maintenence on my 944) and a car that you can relatively inexpensively mod to a Street Prepared Class (coil-overs, H/I/E, LSD, etc . . .).

I know in the case of the mid-nineties GS-R, you can get roughly 170+ HP to the front wheels with a "DC Sports" Header and "AEM" CAI. Pick up a Sport Compact Car and look at the prices on these items to get an idea of the expenditure. I am sure you can get an 8v 944 over 170 as well but I think you'll be dragging an extra 250 lbs. and I would doubt it is price competetive (I love my car but it isn't cheap to mod).

I am in no way knocking a Porsche, again I love my 944, but it is not price competetive in my opinion for this stuff especially if you are using it as a daily driver as well. Now if you are married to the marque then by all means jump in. They are wonderfully built cars with a tremendous amount of R&D in the making of them. I am making the assumption that by "semester" you are in school and that money might not be abound - in that case, compare shop rates and see what might make more sense ($45 vs. $95 per hour is the diff between Acura and Porsche Dealers and $30 vs. $55 per hour for side-work here).

SHRKBIT

Cool. I think we get more like 80-90 drivers at PCA/PNWR autocrosses.

Are you saying you personally have been autocrossing a 928 for several years? What variety? I find my GT lacks nothing in brakes at autocross, though I haven't started left foot braking yet.

This is true of the majority of cars in any classing system. Period. FWIW, next year's tentative SCCA classes look a little more competitive for me.

I'm doing this to learn to drive the car better and for the thrill. Heck, I'm still competing on street tires. The minor mods to my car (wheels, drop links) put me DFL in a small and very competitive non-stock PCA/PNWR class. (In comparison, I've beat the whole analogous stock class 2 out of 3 events this year. Not a fair comparison, of course, but I'm pleased.) Sticky tires and suspension mods are in the plans for next year.

Anyway, I'm getting off-topic from the original post.

R. Miller

I looked towards the 951 (not 944 n/a) thus hp is obviously better than a GSR. Also I assumed the 951 would handle better "out of the box". Unfortunately this is a highly uneducated guess as I've not driven either of the cars. I have all of August to find a car that suits me though. Of course I've always leaned towards the Porsche marque (often defending stuggart against the likes of italy and ford get it ha ha ha hmmmm) so perhaps passion more than common sense drives me towards the 951. I really don't plan to become Fittapaldi with the 951 but would like give racing a try or at least improve my skills in DE. Perhaps my biggest point against honda/nissan is that everybody my age has them. how boring! though i don't want to sacrifice my entire earnings for the sake of being unique.....

R. Miller

just a thought...are tinted windows bad for autox/solo II style racing?

keith

I can tell you, my 951 is even worse than I am at autox. I can beat it in an 8v...

If you do go 951 for AutoX, be sure to get a LSD. nothing else matters as much (besides tires) IMO.

PS - I love autoXing my 951!, but I am NOT competitive, after 1.5 years...

Thom Fitzpatrick

A couple weeks ago I did an SCCA autocross with tons of vettes