suspension advice...
05-22-2005, 04:11 AM
#1
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suspension advice...
I have an Audi A4 Avant quattro...
Right now I am running a KW v2 gewinde.
But I feel its not good enough.
First I feel the rear end lifts too much during hard braking...
I have a pic that show this also:
<img src="http://pictureposter.audiworld.com/40674/brems.1.jpg">
I cant see the front end beeing too soft really, cause it doesn seem to sink to much during braking.
Could some stiffer rear springs help me? linear/non-progressive ones ?
I seem to have to much travel on the rear, cause when I accelrate it compresses alot also.
Actually I have a pic here showing this:
<img src="http://www.pvv.org/~olekvi/pictures/a4_jump.jpg">
and as you see this results in strange things like front end lift. I dont think the frontend really is a problem. It seem pretty good for the car weight, and also handle all the power I have fairly 'ok'...
Any thoughts?
Thanks
Right now I am running a KW v2 gewinde.
But I feel its not good enough.
First I feel the rear end lifts too much during hard braking...
I have a pic that show this also:
<img src="http://pictureposter.audiworld.com/40674/brems.1.jpg">
I cant see the front end beeing too soft really, cause it doesn seem to sink to much during braking.
Could some stiffer rear springs help me? linear/non-progressive ones ?
I seem to have to much travel on the rear, cause when I accelrate it compresses alot also.
Actually I have a pic here showing this:
<img src="http://www.pvv.org/~olekvi/pictures/a4_jump.jpg">
and as you see this results in strange things like front end lift. I dont think the frontend really is a problem. It seem pretty good for the car weight, and also handle all the power I have fairly 'ok'...
Any thoughts?
Thanks
05-22-2005, 05:46 AM
#2
Here you go...
You've really got some issues with your suspension. First of all the springs only help with compression. That is when weight is being applied to them. From your 2nd photo, what you need for the rear to combat the lift problem is more rear shock rebound. The 3rd photo shows a need for more front shock rebound and more rear shock and spring compression. To review, I'd recommend an increase in front and rear shock rebound of 30-40%. I'd also increase the rear spring rate and rear shock compression. I run custom valved Bilsteins that were revalved by the Bilstein folks in Socal. They offer a 3 day turnaround. Good luck.
Hap, wit dakine shocking info from Evahboost
Hap, wit dakine shocking info from Evahboost
05-22-2005, 06:18 AM
#3
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I have tried
adjusting the rebound on the rear dampers...
only thing that was good for was loosing grip over short bumps. rearend still lifted...
I dont think rebound adjustment really could aid the rearend in not lifting. Springrate would have more with this to do I believe.
I agreed on the higher spring rate on the rear.
More front rebound? This would not aid anything but having a slower dampening system in the front and lifting the frontwheels even more from the ground. More rebound would only be effective along with stiffer springs in the front too ?
The Stasis motorsport looks sweet but its pretty expensive I think...
I can add that the third pic is over some really bumpy parts of the track, but it shows things in extreme even so...
only thing that was good for was loosing grip over short bumps. rearend still lifted...
I dont think rebound adjustment really could aid the rearend in not lifting. Springrate would have more with this to do I believe.
I agreed on the higher spring rate on the rear.
More front rebound? This would not aid anything but having a slower dampening system in the front and lifting the frontwheels even more from the ground. More rebound would only be effective along with stiffer springs in the front too ?
The Stasis motorsport looks sweet but its pretty expensive I think...
I can add that the third pic is over some really bumpy parts of the track, but it shows things in extreme even so...
05-22-2005, 07:17 AM
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watch this...
this is where I took the third pic from:
<a href="http://www.pvv.org/~olekvi/ngk-treff-lankebanen-april-2005-divx.avi">video from trackday</a>
and before you ask why my car dont seem to sit in the curves AT ALL, I can add: I am running some old winter/snowtires just to wear them out
205/50-17 dunlop wintersports...
<a href="http://www.pvv.org/~olekvi/ngk-treff-lankebanen-april-2005-divx.avi">video from trackday</a>
and before you ask why my car dont seem to sit in the curves AT ALL, I can add: I am running some old winter/snowtires just to wear them out
205/50-17 dunlop wintersports...
05-22-2005, 10:36 PM
#5
You need to stiffen the springs all the way around. Adjusting rebound won't do didly for long
transitions such as the braking you describe. Stiffening front springs control dive, stiffening rear springs control front lift.
If you can live with the dive, then stiffening the rear should help with exit understeer since you'll have more front rubber planted, and the inner tire that was normally lifting can help pull the car inwards if you set toe out.
However, with dive, you'll loose rear inside tire traction upon corner entry, so you'll have to delay acceleration since our torsen equipped cars don't like rear tire lift
A stiffer rear setup may help reduce dive - depending on the ride height setting. If the springs are stiff and short with matching shock travel, they will lift the car less than softer longer springs which will continue pushing the rear up until the spring travel limits. You can then raise the front springs a bit to make them not sit on bump stops during braking and cornering. Helps reduce dive too.
If you can live with the dive, then stiffening the rear should help with exit understeer since you'll have more front rubber planted, and the inner tire that was normally lifting can help pull the car inwards if you set toe out.
However, with dive, you'll loose rear inside tire traction upon corner entry, so you'll have to delay acceleration since our torsen equipped cars don't like rear tire lift
A stiffer rear setup may help reduce dive - depending on the ride height setting. If the springs are stiff and short with matching shock travel, they will lift the car less than softer longer springs which will continue pushing the rear up until the spring travel limits. You can then raise the front springs a bit to make them not sit on bump stops during braking and cornering. Helps reduce dive too.
05-24-2005, 01:28 AM
#6
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mirror for you
hosts are in norway, so probably slow over to the US. Hosts are superfast for us here in norway.<ul><li><a href="http://temp2.durnk.org/ngk-treff-lankebanen-april-2005-divx.avi">video2, mirror</a></li></ul>
05-25-2005, 05:14 AM
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a little more info for you
I really appreciate your time/views on this. Thanks alot.
Ride height is about 13.25" at the front,
and about 13.5" at the rear.
This is measured from wheel center to fender.
(I dont think ground to fender applies as this of course is wheel dependant)
Camber on the fronts are a few degrees negative. I have no idea what caster is.
And I dont know the exact toe either, but I seem to remember they were set to about zero on all corners, maybe a little toe in on the front.
KW gewinde ver 2, with rebounds on the front 3/4 turns from the tightets, and rears 1 turn from tightest.
Changed to S4 swaybars on both front and rear.
How car handles maybe say a little more.
at corner entrance car is pretty understeered if I go into the curve with no brake applied. If I step on the throttle into the curve it understeers even more. I can brake a little late, with result that the rear end 'twists' alot and seems unstable, and it might even oversteer into the curve if I really push it.
Corner exit depends on driving style. If I apply power little by little it is very neutral, if I apply power all at once it may either loose grip on the rear and oversteer, or just understeer so I have to go off and on again.
Its kind of hard to explain.
(and of course remember my car is a bit 'overpowered' with about 350-400hp at the wheels, and some turbolag)
Before I got the engine I have now and the S4 swaybars handling were even more understeered. And the rear end seemed to just 'twist along' and push the front end out...
I have a rs2 drivetrain, and rear diff that can be locked fully. With it locked I cant have that much speed into the curve unless I throw it into sideways, but I can lightly oversteer out of the curve and can get much more power to the ground.
I barely never use it for other than fun. It just go slower.
I think maybe I could be better with some linear springs on the rear and a little more rebound also. This would probably have the car a little less understeered and hold the frontwheels better on the ground out of the curve...
I dont believe changing things much, except maybe alignment and some bushings to get less deflection, on the front will do much for me.
Of course its all about balance, finding a compromise with what makes the car handle best at curve entrance and exit. It seems we have to live with a little understeer unless we get weight moved a little more to the rear end of the car.
Jamez-
Ride height is about 13.25" at the front,
and about 13.5" at the rear.
This is measured from wheel center to fender.
(I dont think ground to fender applies as this of course is wheel dependant)
Camber on the fronts are a few degrees negative. I have no idea what caster is.
And I dont know the exact toe either, but I seem to remember they were set to about zero on all corners, maybe a little toe in on the front.
KW gewinde ver 2, with rebounds on the front 3/4 turns from the tightets, and rears 1 turn from tightest.
Changed to S4 swaybars on both front and rear.
How car handles maybe say a little more.
at corner entrance car is pretty understeered if I go into the curve with no brake applied. If I step on the throttle into the curve it understeers even more. I can brake a little late, with result that the rear end 'twists' alot and seems unstable, and it might even oversteer into the curve if I really push it.
Corner exit depends on driving style. If I apply power little by little it is very neutral, if I apply power all at once it may either loose grip on the rear and oversteer, or just understeer so I have to go off and on again.
Its kind of hard to explain.
(and of course remember my car is a bit 'overpowered' with about 350-400hp at the wheels, and some turbolag)
Before I got the engine I have now and the S4 swaybars handling were even more understeered. And the rear end seemed to just 'twist along' and push the front end out...
I have a rs2 drivetrain, and rear diff that can be locked fully. With it locked I cant have that much speed into the curve unless I throw it into sideways, but I can lightly oversteer out of the curve and can get much more power to the ground.
I barely never use it for other than fun. It just go slower.
I think maybe I could be better with some linear springs on the rear and a little more rebound also. This would probably have the car a little less understeered and hold the frontwheels better on the ground out of the curve...
I dont believe changing things much, except maybe alignment and some bushings to get less deflection, on the front will do much for me.
Of course its all about balance, finding a compromise with what makes the car handle best at curve entrance and exit. It seems we have to live with a little understeer unless we get weight moved a little more to the rear end of the car.
Jamez-
