Pete has single-adjustable Penskes on his CR.

 

AP1 is different then an AP2 as for dynamic toe in the rear, so not exactly apples to apples comparison. For AP2 they reduced the turn-in to not be as dramatic. Zero toe in the rear for AP1 could be touchy in high speed transitions.

IIRC AP1 spec for rear toe in is 0.25" total and AP2 1/8". Someone correct me if wrong.

In the end it all comes down to driver preference.

I run 1/8" total rear toe in on an AP1.

 

Ours = '01, Marc's = '08 CR, Cubby's = AP1, Glagola's = '06 AP2

Everyone drives their own way.

 

Your probably right, but I have frequently driven an AP1 with the same alignment and mods as my CR and both give the same feedback. I feel they both can achieve similar times. Maybe on paper they are different, but in real world auto-x situations those settings on paper mean little to me when it inhibits the cars ability to get around the course fast. Not saying anyone has to listen to me, but going outside the box (while using the wisdom of this board) is how I personally found more time. Worth considering IMO.

Matthew's S2000 is an AP2 and why I threw the "0" toe comment out there. His springs and ride height changes may be causing unfamiliar issues as well. At higher track speeds, I absolutely would run more toe-in without the assistance of a wing. Still, I know some fast track guys in AP1s with "0" toe. I agree that it comes down to personal preference though. At this point in tuning the S2000 for STR, there is no proven method as of yet. I personally want to see more variety.

Matthew, any chance there isn't enough suspension travel with your setup? Rasing the ride height significantly helped one of the local guys.

-Marc

 

I run 3/16" toe in and its perfect. Makes the car really stable in transients and puts power down well when I don't **** up the front bar settings.


Jim - those settings look good - I'd run with it.

 

All of the above is "on the list." The bump stops that I have a fairly progressive, so I'm not to worried about a rapid change in spring rate on a smooth-ish course.

In fact, one of the ideas that I want to possibly test is to go a little softer (maybe higher too) on the rear and see if the progressive bump stops will help me get rid of some of the corner exit push while maintaining corner entry and transition stability.


RE: Toe. I ran 1/4" stock and thought that was too much. I thought 1/8" would be too little so I split the difference. Also, once you start getting into 700lb/in range, I wonder how much toe change I really have due to cornering.

 

It really all depends on your driving style. Up until Last year, I was running toe out in the rear to get the car to rotate more, but I found out that decreasing rear camber, and going back to 0 toe, I was bale to achieve similar results, so I went from -2.2 camber in the rear to -1.6 and 0 toe, and the car rotates, and is still very stable in fast transitions. That may not work for other driving styles though.

 

Ditch the bumpstops...if those suckers are as short as mine - there is no way you'll ever bottom them out and the bumpstops are just creating some inconsistencies.


I think I ran 1/8 total toe in when I was stock - it worked well with 2deg of camber. I had major issues with the car putting power down on Bridgestones though last year. So I went to 1/4" toe in and ran it like that for most of the season. Worked better, but still had to be very ginger with the throttle.

 

Bingo.


Thats the right way to do it.



A. It gets you more transitional stability in slaloms.

B. Its stands the tire more upright for ProSolo starts and corner exit.

 

I guess I'm just trying to make it so I can lay down power in big lane changes or esses but still be able to keep the front soft enough to have grip mid corner.