car set up advice needed

[michael lang]

I'll be the first to say that I should have attended the clinic on Saturday. I can assure everyone here I was up & ready to make the drive from Wash D.C., even in the pouring rain we had here on Saturday morning but I can only have a second life for so long and must come back to reality sometime. That being said, I am in need of some advice.

I was told last week that when going through T6/T7 that I was lifting the r/f tire. I have also been told that my car does this making the right to climb the hill on bridge straight at Shenandoah. I am not thinking that this is a problem because I haven't been told that I'm slowing people up in those areas of the track, and quite frankly my car feels fairly planted under hard cornering. But, the more I think about it the more I realize that there are even more cars that don't have this condition.

So my question is, what really causes this to happen, and what can be done to correct it so that all four wheels stay planted on the track?

 

[Brian Minkin]

Mike,

I understand that this is normal on a very stiff setup when cornering near the limit. Short wheelbase cars get wheel lift that is extreme. I get wheel lift on my 993 and have pics showing it.  I do not think having all 4 wheels on the ground will be any faster.

[michael lang]

Brian, I'm not looking at it from a speed standpoint, right now I feel like I'm getting to the very edge of my comfort zone. I'm inquiring because I'm not sure if over time, I end up breaking something because of the added load on the l/f suspension.

 

[Larry Herman]

Michael, as long as your suspension components (ball joints, wheel bearings, struts, shocks) are in good condition, you need not worry about any "additional loads" placed on them.  They can handle the cornering forces just fine.

Brian is right when he says that it is exaggerated by the short wheelbase, but even the 996/997 cars do it.  The problem is that the rear weight bias and relatively soft springs cause these cars to "sit down" on the rear suspension, and under hard cornering with full throttle, they will lean and squat enough to lift the inside front.  Running larger sway bars with stock springs makes this worse because typically the front bar is stiffer than the rear.

The only way to "fix it" is to run really stiff rear springs (like on the order of 1000+ lbs) with properly matched front springs.  That will prevent the car from squatting in the back and keep the front more planted, but it is not a 100% cure because I have even seen F1 cars lift their front wheels on occasion!