The results are up on the web site. http://www.windycitymiataclub.com/autox/re...02-06_1_08.html

patinum = 68
Dezoris = 414
IBMcpa = 485
ycsm = 816
PeaceLove&S2K = 47

Not sure if 177 is on here. I'm really trying to relate everyone's names, screen names, faces, cars, and autocross numbers.

 

Pat explained it one way.

I adjust pressures based on alignment and tire roll.

If your alignment is good you should see tire wear right to the edge of the tire near the wear indicator. Some people use chalk or shoe polish to see where the tire rolls.

So basically you need to find that pressure where you are getting the best contact patch.

Every car will be different, because of tires and alignment.

Heat changes pressures as you saw. But also as tires heat up grip levels change.

Find a baseline to start with at cold temperatures.

So lets say 35PSI was the optimal pressure front and rear for your car.

If you were over steering, you could have dropped the rear pressures 1-2 PSI to get more rear grip.

If you were under steering you could raise the rear pressures to lesson grip in the back to balance it out.

If you are confident you have hit a wall in your times, and you are not happy with the balance of the car start with adjusting the rear pressures to suite your driving style.

If you think you can drive better, just drive and worry about pressures down the road.

 

Was 177 on R compound?

 

Yup. I think he said he just got them. I want to say Hoosiers, but I could be completely off.

 

Are any of you running a special alignment for autox? Any recommendations on that, and what's your experience on that with increased tire wear and/or increased twitchiness at highway (100ph+) speeds?

 

I'm running the alignment here:
https://www.s2ki.com/forums/index.php?showtopic=172595

...or at least as close as I can get with my busted ass car. I don't think it's too much, but I've committed to buying tires every year. And my car isn't a daily driver. You might also want to try the UK alignment. Haven't noticed anything at high speeds (135ish - on track and legal).

 

IBM that post Pat made is good reference.

* Front toe - 0" to 1/8" toe out
* Front camber - -1.5 to -1.75 degrees

* Rear toe - 1/4" to 3/8" toe in
* Rear camber - -2.0 to -2.25 degrees

Keep in mind those were determined by use of R compound.
For street tires, stay on the low end of those specs. IMO there is no need for that much negative camber front and rear with street tires.

The grippier the tires are the more body roll. So if you were running R compound the more negative camber you would want.

The 1/8" toe out up front really helps with turn in, makes the steering feel quicker. You can apply that to any car and you will notice a nice difference.

1/8" is not a lot of toe out. You would likely not feel the difference in high speed stability. But you may notice more steering pull over uneven pavement.

-1.5 camber front and -2.0 rear has worked really well on both my AP1 and AP2. Easy to adjust pressures with that alignment to get max grip out of street tires.

I would keep the rear toe at factory specs. A slight amount of toe in on the rear will keep braking stability high.

Zero toe or toe out in the rear will make you go side ways under braking and will make the rear end more unstable.