waddisme

http://s10.photobucket.com/albums/a1...0stability.flv

As soon as I get above 140, car seems to start moving around like that. There is no vibration in steering wheel, just that "floating" around. Seems like car should be more planted. I have checked the rake according to Au engl specs, ride height is still stock, I have all the air dams on the front, but no spoilers etc. Shocks are Pfadts set at 12 front and 11 back. I keep tire pressure adj to 38 lbs when I come in from a session. Is this normal? Any adjustments to make? TIA.

jmorgan07z06

That does not look normal to me. What kind of tires are you running?

waddisme

PS2s front and rear. They are 295/30/19 on the rear and 265/35/18s for the fronts iirc with plenty of tread.

Solofast

The floating is happening as he top of the hills. Most likely the result of too soft a rebound setting on the front that is letting air get under the nose of the car as it crests the hill.

WNDOPDLR

The crest of the hill on the back straight at VIR is subject to some very heavy cross winds. I always advise my students to get track center going over the crest, which is something Falcon tought me. I think any high HP car without added aero's is light at that point, and, judging by the sky, it may have been a stormy, windy day. I know my car has been shunted considerably sideways under very bad conditions at just that point. Have you experienced this at any other fast tracks like RA?

waddisme

I never have thought about it in relation to RA. Car always seems very uncomfortable doing turn 9 at RA, which I am guessing is about when I would be crosssing 140. Seems like I am having to use more steering there than I would like. I will dig up some video from back in June to compare. Interesting. In fact, I don't remember it being an issue at Lowes last July when I was doing 150+ on the backstretch. Need to go look at some video there also.

davidfarmer

perfectly normal, just drive through it. The "straight" isn't really straight, and it definitely isn't flat, it is loaded with little plateaus that constantly unload the reload the car. You notice it more in corners, where loading/unloading/camber/off-camber add and remove grip, but to me it's the same thing.

At 160+ on a breezy day, it is scary as hell, and I've even seen the AH light come on in students cars, but I've always just powered through it. Oh, how nice a bit ($4-5k/s worth) of Aero would be...............

Z06cool

When I was there in July in the Z06 and Pfadts and T1 bars, I felt that also. I bumped the fronts up and that corrected the "loose" kind of feeling up front. 14F/14R.

waddisme

That makes me feel a little better, even though I would prefer the nice planted feel.

I have only had my Pfadts for like 3 track days and there is always been some kind of issue so I haven't had the opportunity to play around with them. The 14F/14R looks like a good direction. Thanks.

Z06cool

When you go back to VIR and re-test. Try it with your setting and then the harder settings back to back.

davidfarmer

oh btw I'm not saying it can't be tuned out, but it is normal in most every car I ride in with any speed. I don't think it likely to actually cause you to lose control.

no spin

My stock 05 did the exact same thing at that speed. When I got home I had my R888s balenced and an alignment done. (my alignment was off) I went back to VIR 2 weeks later and the floating around was gone.

Falcon

That didn't appear too bad.

In fact, the feeling of lightness is rather exhilarating, kind of like a covey of quail flying out of your ***.

Z06cool

Jody, I know down at the Pine Key Adult Resort and Entertainment Complex that may be fun but having a "covey of quail flying out your ***" sounds painful to me...

WNDOPDLR

You sir, are not well.

Falcon

A covey of quail isn't bad, but a herd of hampsters....that's another story entirely!

JDIllon

As most above have stated, this is pretty normal. Do you have Pfadt sways?? Mine did it at VIR and I talked to the GM guys. They suggested a little more rake and double check your alignment, to much tow, in or out can also cause this feeling at high speeds. They also stated that the steering wheel needs to be dead straight when the car is going straight. JD

AU N EGL

38 psi is too high. 32 front 30 rear Cold for Mich PS.

Now MAY have to adjust the rake slightly. But like everyone else says, that really was not too bad, for what is going on. Your climbing a hill, the wind is normally out of the North there, so the wind is coming at you and lifts the front of your car slightly.

Over all not bad, Just DONT LIFT

2K3Z06

you got too much toe. I had my car setup for autox, a lot of camber and a lot of toe. It was a little "darty" above 120 mph. reset your toe, front and rear and your high speed problems will probably go away.

waddisme

I still only have the stock Z06 sways. I haven't had alignment done in almost 2 years so maybe it is time again. Maybe it just feels scarier than it is. Really need to do the racing seat thing too.