autoxEX

Hey do any of you guys autocross? I was curious what tire pressures you guys have it at. Oh, for those in the NY/NJ/PA/DC/MD/VA, I plan on attending some events this year located in Philly. Here is the website for those interested: http://www.autox4u.com/phillysnow.htm

jaysonx

i run 40 up front and 36 in the rear, but i drive a delsol

NJTom2000

autoEX, I did an auto-x at the Camden,NJ location that the Philly region uses, only I went to a South Jersey region event there. Nice big parking lot right on the Delaware river across from Philly. It's about an 1.5 hour drive for me so I'll stick more to the North Jersey events this year, and maybe make one event down there.

FYI as for Tire Pressure, I just bumped my pressure up close to 40PSI based on general recommendations I saw. I'm too much the novice to worry about that right now. I'll know better after next season.

-- Tom

solo2racer

Here's a message I sent out to the S2000-motorsport e-group mailing list. Join the list for more autox info.

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Hey all -

At yesterdays Chicago region event, I drove a couple friends' S2000s. They were both completely stock, except that one was running on Kuhmos (225/245) and the other was running on the OEM street tires.

Both had OEM alignment settings and no other adjustments (no bar, shocks, etc).

I raced the one on Kuhmos during the event for 5 runs, and then took 2 fun runs in the one on street tires. Conditions were about the same all day - overcast and about 70.

I started at 31/30 f/r with the Kuhmos.

The first thing I noticed with the race tires is that the back end was loose, but also uncontrollable. It seemed like every time I would put my foot down, the back end would step out, but it would step out in a quick lurch. Not good for my confidence. My time was about a 59.8.

I then tried raising all the pressures to see if the back end could be better controlled. I went up to 36/34 f/r and took 3 runs that way. I really couldn't tell the difference at all with the higher pressures.

As my confidence went up a bit, I got down to a 57.3 dirty - waaayyy dirty, +6 cones ;-)

For my last run, I dropped the rear pressure 2 psi to 32, so I was running 36/32 f/r hot. On the run, I immediately noticed that the back end was looser, but that it was controllable (and not twitchy). It didn't step out in a jerk, but was smooth. I was able to move the back end around without fearing it would snap on me.

Since I didn't have a clean run, I had to back off in a few spots. I had to pretty much park it in a garage (I hit a cone in the garage on all of my previous runs). I still ran a 58.1 clean, and I know I was significantly slower coming out of the garage into a long straight - on all my previous runs I had hit the rev limiter about 6 times, on that run I didn't hit it at all. I also made a few other mistakes that cost time, so the run would definitely have been faster than any of my previous ones.

Now the plot thickens.

I jumped into another friends S2000 on street tires for run runs. He had the OEM tires set to 38/34 F/R. My first run out, noticed that again the back end was loose, but it was controllable and was confidence inspiring. I was not hesitant at all in putting the hammer down in turns and letting the back end step out. But it was catchable. My first run was a 57.3 clean. My second run was a 57.2 dirty, but I got sideways in 2 spots and would have had a low 56.x easily.

Some observations -

- The OEM setup of the car is extremely well done
- I think if I had started with the race pressures where I ended up, I would
have had been faster on the race tires
- Confidence and trust in the car is _everything_
- The car responds to small changes in tire pressure (2psi) quite
significantly
- I gotta get me one of these things ;-)

In comparison to other times for the day, the car was quite a bit off the pace. Alex Tziortzis set FTDi and had a best time of 54.226 in his Z28. Jason Saini ran a 55.5 in his VW and Chris Dvorak ran a 53.3 in his RX7. They are all excellent drivers in very well set up cars so I don't feel too bad about it ;-) If I had been able to get the car into the 56.x range, I think I would have been extremely happy.

I hope this makes sense to someone and maybe even helps them ;-)

cthree

I have noticed running on OEM S-02's that the right pressure for me is about 36 cold f/r. Less (32) and I had big-time understeer, shoveling through the corners. More (39) and the rear is a bit too twichy, very difficult to apply throttle without breaking the rear end loose.

I have now got a fresh set of A3S03's and will have to do some experimentation. Any ideas?

Jason Saini

C3... With the Hoosiers, I'd keep the pressures around the same. In fact you may end up being a little higher in the Hoosiers. Some of the Miata guys run 38 front and like 34 rear in Hoosiers, could make a good starting point.

With the S02's we had good luck running 38/36 I think? But we did pick up a push by the end of the day after the fronts started wearing funny.