thielepr

I just went to a track day last Sunday. It wasn't my first time at the tack but it was my first with the S2k. I went with the crappy tires that my car came. It's a AP1 with AP2V1 wheels with stock size front and rear.

The front tires are some sunfull tire That I 've never seen before and the rears are Kumho SPT. The car was with 32 steer PSI in all tires. Like you will see in the video below, I spin out the car two times in the same lap. The fisrt spin wasn't such a surprise but the second was with no advice. The crappy kuhmo (not the brand, this model isn't suit for the tack) was hot hot hot with no grip. I finish the heat and talk to some "expert" that say to me that my tires won't work at the track (Like I didn't know) but just to past the day and have some fun down the rears to 28.

After that, the day get a little rainy and the tracks wasn't so hot. So, no more hot laps but fun laps. After put the rears to 28 I notice in the first turn understeer and then the common AP1 oversteer that is ok to me. I didn't like the undertseer and it appears after down the rears to 28. I've search the forums and realize that I was running too low. I will fix that on teh next event. I just order two 225/45/17 RS-3 for the front and next month will be order the 255/40 rears.

I didn't know that running low PSI in the rears compare to the fronts will cause understeer. Does anyone have the same experience or it's just my crappy front tires?

BTW check out the video. yeah I know old style camera video. I will get a hero cam too.
S2000 Track Day spin out

ddess

Total Blair Witch video.

But yes lower tire pressure will give that side more "grip" and in turn making the balance change. Plus 28 is way too low assuming that s hot PSI.

Orthonormal

a) Different tire models require totally different pressures.

b) Kumho SPTs are a great cold weather / standing water tire, not so great when it's hot & dry.

c) Bad idea to mix tire types -- The Hankook RS-3 hates the cold, the Kumho SPT hates the heat. Your balance will change a lot as the tires heat up.

d) Lower tire pressure will only give that end more grip if you have your pressure set too high to start out.

thielepr

c: I know I won't be to the track until I have the four RS-3

PedalFaster

Actually, in both cases your spins were due to lifting off the throttle in mid-corner and not countersteering enough to correct. Independent of what changes you make to your setup, you should work on correcting both of these bad habits, which will otherwise bite you hard on a faster track.

[QUOTE=ddess,Aug 26 2010, 07:12 PM]lower tire pressure will give that side more "grip"

Forcednduckshn

The rears were definitely cooked from your previous spin, hence why it was easy to loop it the second time. Consider working on your driving technique as others have mentioned. Focus on being smoother and getting on the gas early and progressively to balance the car as you move through the corner. I saw alot of lifting after diving in to the corner and sliding the car a bit too much. Bad habits, especially for our torque challenged AP1's.

Nick

thielepr

I really appreciatte your comments. I don't consedier my self a rookie, but I still need a lot of practice and input like yours. I was two seconds lower than a CR. For the moment that my mark. Let see

Orthonormal

Just watched the video -- It looks like you are entering turns with too much speed, and trying to scrub off speed by lifting off the throttle or braking. That's making the rear end loose.

Your line through the turn where you first spun was consistently a very exaggerated late apex, where you are driving the car to meet the inside edge of the track just where the curve meets the straight. That line combined with the deceleration all the way through the turn is causing a very slow exit speed.

Brake earlier and more, don't apex quite so late, and you will be able to start your acceleration out of the turn much earlier.

That's my impression based on the video. As usual I agree with Steve.

I'm guessing that your camera mount is a two-legged type?

thielepr

yeah two legged type, I will work on that too. Thanks for your comments