smokey

The front wheel lifting could be the result of the rear bar being set to full soft. Try the middle hole to reduce understeer. But I don't understand how you could have both rear and front wheel lift. On the high speed sweepers, at what point do you get the rear wheel lift? Just at turn in? That's the way front wheel drive cars are set up, to counter understeer. I've followed a Sentra SE-R race-car entering turn 8 at Mosport where the inside rear wheel was six inches in the air at turn in. Rear wheel lift would be due to a stiff rear sway bar, and yours is set to full soft. The other possibilty is that your rear shock is too stiff, and this is causing the rear wheel lift, especially if it's just temporary at turn in.

Geo

Actually, in the case of the SE-R, in addition to probably having a stiff rear bar, those cars are flexi-fliers without a really good welded cage set-up.

The too soft rear bar still does not explain the lack of front droop.

BTW, do you know who was driving the SE-R?

smokey

I can't recall who was driving the SE-R, but it was at a Dexter Day open track event which is run what you brung. There is a very competitive spec SE-R race series here, sponsored by Nissan, I believe, and it was one of those spec cars. They do have cages, but I believe they run on street suspensions or very close to it. $$$ doesn't talk in this series. The cars are very close to identical, and the difference is in the driving - with some very good drivers. I think the peeing-dog stance at turn-in is part of the package on these cars, but what impressed me most was the fact that I saw no brake lights at the end of the straight . The only other cars I've seen do that at Mosport are spec Miatas, which don't lift their hind leg on turn-in. Sorry, getting off topic. On the 944, I think the most likely problem, unless the sway bar is sticking, is too stiff a rear sway bar plus stiff rear shocks. If a rear wheel is in the air at apex, your limited slip won't last very long. Any car set up for understeer, i.e. with a loose rear bar, will lift a front wheel. I've seen a Lotus Elan vintage racer with its inside front wheel just barely touching the pavement rounding turn 9, and there are very few cars as well balanced as an Elan.

keith

I'm going for a combination of too much bar AND too much rebound.
(but mostly rebound)

If I'm right I want a dollar.

FormulaOne10

I was very close to lifting the inside wheel with my 84. It only had 26.8mm front and 18mm rear bars. With stock spings a little negative camber and only rear koni yellows. My vote is also for the sway bar. I attatched a pic so you can see the wheel lift. Keep in mind the turn itself is elevated slightly on the left side.

924RACR

But here I'd also want to see the rear wheel. My 924 (same suspension, of course) leans very evenly, and I have many pictures of it lifting nearly both inside wheels; good photos, taken at a real low angle, showing all 4 wheels. For example (bottom right corner, note shadows on inside wheel):


I don't think this one counts, excessive curbing :


Here you can see the tires leaning pretty hard:

Adam Richman

I am thinking its an illllllussssion At least on the rear. Here's a picture of my porker ... no rear sway bar at the time and the rear looks like its coming more off the ground than the front. This was one of the first few events I did in this car and the rear had too much negative camber (3+ ° IIRC) as you can see by the outside rear not even at vertical but the inside rear is on half it's contact patch.

If making guesses, I'd think the fronts having too much rebound damping would be the culprit prior it being the rear sway bar if the rear is coming off the ground in long sweepers. If the rear is never physically leaving the ground, it might just be a visual effect of too much negative camber. As for the inside front coming off the ground (what would this be? humping cat?), I'd tend to think this not too unlike our peeing dogs in FWD cars.

Oddjob

Finally found the info: my bilstein valving is 600/180 front and 565/218 rear. Im not familiar with the units or convention for valving, so can someone explain these numbers?

924RACR

Those are compression/rebound (in order). I do not believe they are specific damping rate numbers, but rather more related to perhaps orifice sizes or the like. Sounds like a fair bit of rear rebound damping, but not obscene; I still do have to agree with the general direction of this discussion which is pointing at: get some photographic evidence.

These cars (as plenty of pictures besides my own have shown) look somewhat unusual when cornering. When I went through driver's school on the stock sport suspension, nearly every cornerworker I knew came up to me and told me that it looked like my Panhard rod was broke! Don't get it.

JCP911S

Lifting wheels is not necessarily bad. Key is to get neutral handling. Mostly wheel lift is a result of the spring rates being different front to rear. The car will tend to "pivot arount the outside wheel with the most relative roll stiffness, lifting the inside wheel on that end.... like a chair with uneven legs...

This is most pronounced on cars with extreme weight bias... 911s and front drivers. Reducing spring rate on the heavy end and increasing on the light end (either with bigger springs, sway bars or some combo) helps neutralize the handling but creates a big difference in roll front to rear... result.... lifting inside wheel on the ligher end of the car.

This is just a compromise created by the non-optimal relationship between weight distribution and tire size.

Stiff sway bars probably exaggerate the visual impact of this as they also tend to "lift" the inside wheel as the outside compresses.

More surprised to get alot of wheel lift on a more neutral car such as 944, but the same principle still applies I suspect.

Also application of brakes and accelleration will also cause weight shift and wheel lift.... trail braking will increase front compression, accelleration rear compression.... so you really see exaggerated rear lift on front drivers entering a turn under trail brake, and on 911s exiting a turn under power.

RogerJ

Lifting the inside front tire is due to a lack of roll stiffness in the rear. It could be a variety of things, but the fact that you have the rear bar in the softest setting makes this easy to test. This, however, does not jive with the "power oversteer" you say you experience. A car that is too soft in the rear understeers. You might want to get someone else to drive the car and see what they think.

Danno

Don't forget that trail-braking in to a corner makes a difference in the lateral weight transfer. In some corners, he may be able to carry enough braking in to transfer more weight onto the front to raise the inside rear. Other corners, you may be able to get on the gas early as you're hitting a bump or something and lift the front.

JCP911S

Danno, like the avatar... looks like a good way to get more weight on the front... like to try that on my 911 some time...