Background:
My last event was a little unusual for our region. I usually barely get above 40 miles per hour at an event, due to lot size. Lot is concrete in great condition. The last event, however, had a loop that wound up getting a very fast sweeper for our AutoXs, and I noticed a trait that might have costed me some time.

On the fast sweeper, it tightens up in the middle, but opens back up. It was kind of parabolic. It went fast --> medium --> very fast.

I would wind up braking a bit to make it through the medium speed portion and get back on the gas to finish out the sweeper. When I would get back on the gas, the rear end would step out just a little, and it would drift a bit through the corner. (By "just a little", I maybe put 10 degrees of opposite lock to guide it properly through the corner.) At slower speeds, it would have been a big dorifto or a spin losing lots of time.

Question:
Did I take that fast sweeper correctly? Could I have changed tire pressure or something to keep the rear planted and take it faster?

Setup:
275/35r18 Dunlop star Specs all around
38psi front/35psi back
Hotchkis sways f/r F: 3/4 stiff (2nd shortest arm) R: middle stiff
alignment 1/16" toe out front 1/8" toe in rear, -2 degrees rear camber
otherwise stock
3/8 tank of gas
spare tire in car

 

Do you chalk or take tire temps? That may be a little on the high side. If the car oversteered after the apex, that could be due to too much gas, too much steering input, an improper line, or any combo of them (and others). You could also loosen the rear sway bar to dial out some of the oversteer.

If the turn is fast in, medium within, and really fast out, that sounds like a late apex turn to get a running start for the exit. It's hard to comment without knowing a bit more.

 

I don't have a pyrometer (I'm still on the newish side; don't have too many toys), and I've yet to get a camera to record my runs (on the list, though).

It was definitely post-apexing oversteer. Once or twice, it felt like I had a little braking understeer, then neutral, then slight oversteer. always slight oversteer though. A number of guys spun out at that exact point.

If it would be helpful, I could link to a few runs of the same course by other cars and identify the turn in question.

 

That may help, it won't hurt.

 

The curve in question is at 0:26-0:31. I kept taking a wider arc than this guy, and transitioned to oversteer at about the 0:29.5 point.

http://www.youtube.com/watch?v=5r54F...layer_embedded

 

When racing, a little slip angle is good. If you're concerned about too much slip take out some rear sway stiffness and/or lower the rear pressures a pound or two. Although the pressures sound about right.