s2000 autocross, anyone knowledgeable?

I'm trying to find some info for my dad. The s2ki.com hasn't helped so I'm sure that someone here has the answer. He has a 2004, and wants to run it in the new street class, o staggered bfg rivals. Right now he's trying to figure out his best options for sway bars to fix his overstter issues. All of the right ups on s2ki etc are for the old (stupid stupid stupid) rules with r compound tires. our sites have crappy gravelly asphalt, and with the less sticky tires I don't think he should need near as much sway bar as those write ups are suggesting. Does anyone know what would be a good set up?

In reply to icaneat50eggs:

Did you check the forums?

It took only a couple of minutes to find this: http://www.s2ki.com/s2000/topic/904870-str-prep-sway-bars/

The STR Prep thread has 18 pages of info that look to be very useful.

Yeah but he doesn't want to be in str. I read that thread but doesn't str mean r comps? Am I wrong when saying those bars would be way stiffer than what he needs)

STR is Street Touring Roadster. It's a class where you're allowed whatever shocks and springs you want, whatever swaybars you want, whatever tuning to the stock ECU you want (or a piggyback, or a can of worms in shoving a new ECU into the original housing), and 200 TW tires on up to 9 inch wide wheels. It's also the class where S2000s take the top 5 spots at Nationals year after year. It's a very good (and pricey) home for them.

For Street class, you're allowed the same width as stock for that year of car and +/- 1 inch of diameter on a per-axle basis. If you want smaller wheels for cheaper tires, go for it. If you want a wacky stagger, go for it. All that matters is the width of each wheel is stock.

Another, less desired tip is for him to keep racing the car until he knows exactly what the car needs to oversteer less, then, he buys a sway bar, or two. You can also use tire pressure to raise or lower oversteer tendencies.

In reply to Mr_Clutch42:

Bingo, someone else's build might not work for someone else's driving style.

Also, for the street class, you are only allowed ONE rollbar to be changed.

The base setup for the AP1 or AP2 for autocross is this; 1. Big front sway bar. 2. The front suspension has adjustments for caster and camber. Use them in combination to maximize front camber, even at the expense of caster. 3. Zero Toe in front 4. Run at least as much camber in back as in front. 4. On the back, run toe-in at the high end of the factory tolerance, to help stabilize the rear.

Whether you like it or not, the big front sway bar is needed, even with street tires. It keeps the car from diving in front and hiking the rear end. The rear suspension toe's out when it's extended, and that's what causes the snap-oversteer.

In reply to yamaha: Yeah, I remembered about the Street rules, but often times, people don't want to stay with the Street Class. Sway bars are also considered a fine tuning devise to get handling how you want, not the primary device to adjust.

Yep, you need a big front sway bar. If you can find a Saner, thats a good bet.

icaneat50eggs wrote: Yeah but he doesn't want to be in str. I read that thread but doesn't str mean r comps?

This is where a rule book becomes a handy tool; all the ST classes are restricted to non-Rcomps. Please don't read that in a "he's being a dick" kinda way because knowing what's allowed (and what isn't) is important. Simple, modest mods could put the car in STR whether you like it or not.

icaneat50eggs wrote: Am I wrong when saying those bars would be way stiffer than what he needs)

That may be a very wrong presumption.

Bear in mind that 12 of the 25 B-Street entries in this weeks national championship event were S2000's. The odds are very strong that most (if not all) of them had one of those bars installed.

But, the easiest and cheapest to way to solve the oversteer issue is to use the alignment specs recommended earlier in the thread and then learn how the car drives that way before randomly throwing money at various parts.

He has the alignment already, and this is his third season with autocross, so he has a decent feel for how the car handles, this is just the missing piece. It looks like the str recommendations should do it

We have a couple of S2000's in our regions. One is very well prepped for STR and driven by an experienced driver. He still spins it once in awhile. There's really no getting around the fact it's a tail-happy car. If driven on the edge of control, it's simply a fact of life.

djsilver wrote: The base setup for the AP1 or AP2 for autocross is this; 1. Big front sway bar. 2. The front suspension has adjustments for caster and camber. Use them in combination to maximize front camber, even at the expense of caster. 3. Zero Toe in front 4. Run at least as much camber in back as in front. 4. On the back, run toe-in at the high end of the factory tolerance, to help stabilize the rear. Whether you like it or not, the big front sway bar is needed, even with street tires. It keeps the car from diving in front and hiking the rear end. The rear suspension toe's out when it's extended, and that's what causes the snap-oversteer.

This is especially true for stock class where people used to use R-comps. The snap oversteer isn't caused by the rear bump steer though(unless you have a very early AP1), but by lifting the inside rear wheel. This unloads the Torsen, and the wheel just spins and spins. The truly fast STR cars you see will generally have a clutch-type diff installed in place of the OEM.