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Old 07-17-2007, 08:10 AM   #3
SVT Robzor
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Join Date: Aug 2005
Fan#: 26230
Location: Cumberland, Maine
What I Drive: 2004 CD Silver SVT

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How is the car behaving currently? Is it pushing, is it too loose, or is it pointable?

I'm still fresh to autocross, but it seems the fastest FWD cars will be those that are loose in corner entry for initial rotation, but not so loose that you can't nail the tail down immediately after with the throttle. I'm not sure what the front and rear rates are for Sportlines, but conventional wisdom here is that the stiffest axle-pair will slide first. If you are running stiff front springs, weak rear springs and equal sway bars, your car will tend even more to push, which is typically slower.

If you're pushing (understeering) too much, you can add front negative camber, or try dropping your rear tire pressure a few PSI. It sounds contradictory, but you will gain grip by adding pressure, until the point that the contact patch starts to round out. Cornering work is done by the tire's shoulder, lower pressure lets the contact patch roll onto the sidewall, which is not made to grip.

Lately I've been running 44psi front/34psi rear in my Eagle F1 DS-G3s, which have such insanely squishy sidewalls that I NEED that much air to keep them from flobbing around like cookie dough. The Azenis have much, much stiffer sidewalls, you can probably drop your pressure a little, until you see the scrub marks using up the entire shoulder. I've always had trouble with the SVT being too pushy in transitions, so I typically run a lower PSI in the rear to mitigate some of the grip there.

I've read before that you shouldn't adjust your pressure more than 2PSI at a time, which makes sense to me. I probably wouldnt slide all the way to 34/50 at once, but I'd nudge it in that direction gradually and see how the car starts to act differently, or try going the other way. On some cars, like DS Integra Type-R's, I've read a lot of people will pump TONS of air, like 60PSI, into the rears because the chassis is so pushy in the first place, they need to shrug a ton of rear grip to get the car to change directions - with our stiff rear suspension though, you might not need to do the same.
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