Suspension: lifting inside wheels while cornering
#1
Rennlist Member
Thread Starter
Suspension: lifting inside wheels while cornering
I have a track prepped 944T, running bilstein struts and coilovers with torsion bars.
I have been told by guys that have followed me, that my car will lift the inside front wheel going through carousel type turns, and that it will nearly lift the inside rear in high speed sweepers.
Ive followed other well prepped 944s through these same turns and have never noticed one looking like it was lifting or almost lifting inside wheels.
I cant think what would cause this, other than the shocks/struts don’t have enough droop. But I cant believe the car has more than a couple inches of body roll. Or that it has too much roll stiffness, but my setup/sway bars are not any stiffer than other raced prepped 944s.
Any ideas?
I have been told by guys that have followed me, that my car will lift the inside front wheel going through carousel type turns, and that it will nearly lift the inside rear in high speed sweepers.
Ive followed other well prepped 944s through these same turns and have never noticed one looking like it was lifting or almost lifting inside wheels.
I cant think what would cause this, other than the shocks/struts don’t have enough droop. But I cant believe the car has more than a couple inches of body roll. Or that it has too much roll stiffness, but my setup/sway bars are not any stiffer than other raced prepped 944s.
Any ideas?
#2
Addict
Rennlist Member
Rennlist Member
Hmmm... odd to be lifting wheels at both ends... perhaps not enough fore-aft damping to control weight transfer? What exactly is your setup, and what valving do you have in those dampers (are they race or HD street units)?
#3
Addict
Rennlist Member
Rennlist Member
There's nothing wrong with it if your lap times aren't slower than the non-lifters, the inside wheel's doing nothing anyway in those situations.
Sam
Sam
#4
Rennlist Member
Thread Starter
They are the full race bilstein with the "turbo cup" valving. Im running 500 lb/in springs in front and an equivalent rate with the helper spring and torsion bars in back. 968 M030 sway bars.
Im the only car in the area using bilsteins, the other equally prepped cars are using koni dbl adjustable setups, with approximately the same spring rates. If I am lifting inside wheels and the others are not, Im very curious as to why.
But I am also not convinced that my car is actually doing anything different than other 944s. I may just be getting some exaggerated statements from others.
Just wondering if anyone else has seen this or dealt with it as a problem?
Im the only car in the area using bilsteins, the other equally prepped cars are using koni dbl adjustable setups, with approximately the same spring rates. If I am lifting inside wheels and the others are not, Im very curious as to why.
But I am also not convinced that my car is actually doing anything different than other 944s. I may just be getting some exaggerated statements from others.
Just wondering if anyone else has seen this or dealt with it as a problem?
#5
It sounds like your sway bars are too stiff. Try moving the adustments (if it is adjustable) closer to the ends of the bars. If not adustable, try a thinner bar. This will even out the contact patch on the inside tires. A tire in the air gives NO grip!
Trending Topics
#8
Addict
Rennlist Member
Rennlist Member
Maybe perhaps the guys who are following you are pi$$ed that they can't catch you, so are trying to psych you out and mess you up?
Right, I'm with Greg, I have to think that, assuming what people are telling you is true (and try to get pics, that's the best way to know for sure, station friends with cameras) and BOTH ends are lifting, I would suspect that rebound damping settings on the shocks are too high. I have some numbers for valving in the Bilstein catalog at home, but you need to know what you have (if this is an issue, in order to address it).
If the car really is doing this (particularly as a result of too much damping on rebound), it should be pretty tail-happy on the brakes and push pretty hard when you're on the gas.
Another approach would be to contact Bilstein Motorsport, explain your setup to them including corner weights, and request their recommendations for valving. You might likewise consider shipping your shocks/struts to them for revalving to these recommendations. I sent mine in a little over a year ago, turnaround wasn't too bad at all, and they're only $55 each shock or strut. For my case, I just went with their recommendations off the shelf, and havent' had cause to complain yet (though I've not been able to really fully test the car out still, due to engine shortages).
Right, I'm with Greg, I have to think that, assuming what people are telling you is true (and try to get pics, that's the best way to know for sure, station friends with cameras) and BOTH ends are lifting, I would suspect that rebound damping settings on the shocks are too high. I have some numbers for valving in the Bilstein catalog at home, but you need to know what you have (if this is an issue, in order to address it).
If the car really is doing this (particularly as a result of too much damping on rebound), it should be pretty tail-happy on the brakes and push pretty hard when you're on the gas.
Another approach would be to contact Bilstein Motorsport, explain your setup to them including corner weights, and request their recommendations for valving. You might likewise consider shipping your shocks/struts to them for revalving to these recommendations. I sent mine in a little over a year ago, turnaround wasn't too bad at all, and they're only $55 each shock or strut. For my case, I just went with their recommendations off the shelf, and havent' had cause to complain yet (though I've not been able to really fully test the car out still, due to engine shortages).
#10
Rennlist Member
Thread Starter
Ill get the shock/strut model numbers and look into the rebound valving. I know they are an off the shelf setup from Bilstein, not custom valved.
The front sway bar is a factory non-adjustable bar, the rear is a 3 way factory adjustable unit, set to full soft.
With the spring rates Im using, the car doesnt have much dive or squat and is relatively level through a corner. It has some power on oversteer at the limit. I am looking at using a smaller diameter rear bar or go with a slightly lower rear spring rate to dial out the oversteer.
Ive run both 8x16s all the way around and 8 and 10x18s. Most of the cars Im comparing to are running 18s.
Thanks for the ideas.
The front sway bar is a factory non-adjustable bar, the rear is a 3 way factory adjustable unit, set to full soft.
With the spring rates Im using, the car doesnt have much dive or squat and is relatively level through a corner. It has some power on oversteer at the limit. I am looking at using a smaller diameter rear bar or go with a slightly lower rear spring rate to dial out the oversteer.
Ive run both 8x16s all the way around and 8 and 10x18s. Most of the cars Im comparing to are running 18s.
Thanks for the ideas.
#11
Race Director
I also would look at the swaybars. It's possible the rebound adjustment is too high, but swaybars is more likely. Be sure to check for bind in the swaybars as well.
As already suggested, photos would be helpful as well. If the photos show plenty of droop it's probably something else, but my money is on the bars.
BTW, I've heard that one reason the fronts of 911s are set up so stiff is to counteract the natural oversteer of the 911. Don't know if that is true or just how things worked out.
As already suggested, photos would be helpful as well. If the photos show plenty of droop it's probably something else, but my money is on the bars.
BTW, I've heard that one reason the fronts of 911s are set up so stiff is to counteract the natural oversteer of the 911. Don't know if that is true or just how things worked out.
#12
Rennlist Member
Thread Starter
If its the sway bars, then everyone running the factory 30mm front bar and 19mm rear bar (a very common upgrade) should be seeing a similar characteristic. Is that true?
I lifted the car off the ground on one side. The front droop is only 1.5" and the rear is 2.5". There is at least another 1" of travel in the front struts when the suspension is not loaded/compressed by the swaybar. Im not sure if there is much more free travel on the rear, since the torsion bars are set to ride height.
I lifted the car off the ground on one side. The front droop is only 1.5" and the rear is 2.5". There is at least another 1" of travel in the front struts when the suspension is not loaded/compressed by the swaybar. Im not sure if there is much more free travel on the rear, since the torsion bars are set to ride height.
#14
Rennlist Member
For what it's worth, both my stock 944 and stock 968 lift the front inside in similar situations. This is on street tires and/or race tires, same behavior.
#15
Race Director
Originally posted by Oddjob
If its the sway bars, then everyone running the factory 30mm front bar and 19mm rear bar (a very common upgrade) should be seeing a similar characteristic. Is that true?
I lifted the car off the ground on one side. The front droop is only 1.5" and the rear is 2.5". There is at least another 1" of travel in the front struts when the suspension is not loaded/compressed by the swaybar. Im not sure if there is much more free travel on the rear, since the torsion bars are set to ride height.
If its the sway bars, then everyone running the factory 30mm front bar and 19mm rear bar (a very common upgrade) should be seeing a similar characteristic. Is that true?
I lifted the car off the ground on one side. The front droop is only 1.5" and the rear is 2.5". There is at least another 1" of travel in the front struts when the suspension is not loaded/compressed by the swaybar. Im not sure if there is much more free travel on the rear, since the torsion bars are set to ride height.
It's a swaybar issue IMHO. It may be too large a bar or more likely the bar is binding. On our ITS Sentra SE-R we had the same problem until we dinked around with the swaybar bushings on our aftermarket bar. The bushings were binding so badly there was little wheel travel including droop.