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Discussion Starter #1 (Edited)
i've noticed this for a while now and idk what i can do about it to fix it. first off a little info. suspension is koni sports with h&r front springs and modified stock rear springs with 1.5 coil cut off the top. pss tires all around and dinana rsb with new links and they are set on the inner most holes. now before we go and say you cut the springs, thats the problem, blah, blah, blah, i had a bilstein pss kit before this setup and the issue was there as well. the situation, when taking a sweeping corner it feels like the rear end wants to step out. almost like it looses traction for a split sec, regains, then does it again in a continuous rhythm. has anyone else ever encountered this?
 

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I would start by getting the car on a set a of corner scales to confirm that the corner loading is correct and equal (L-R). Next step would be the alignment.
 

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Discussion Starter #4
alignment is spot on, diff is ok. its more like theres too much roll in the back end. maybe the whole thing is in my head, idk. i can say one thing though, these koni sports are weak shocks. i have a set of rear bilsteins in my closet that have a ton of miles on them and must be 10yrs old and they have more damping in them than the koni's right out of the box. if i put all my weight on the koni rear i can easily compress it, the bilstein i have to really push down to fully compress it and it comes right back up quick. i'd throw them in the rear but i have a feeling it will really ride like crap as these are so much stiffer. plus idk if its a good idea to run them in the rear and konis in the front, thoughts?
 

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Does the oscillating oversteer occur while turn in one direction or both?

One cause for oversteer is the from the rear end getting light (too stiff in relation to the front). If your corner loads are correct try softening the rear sway bar. If this doesn't completely fix the issue try stiffening the front dampeners and softening the rear.
 

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alignment is spot on, diff is ok. its more like theres too much roll in the back end. maybe the whole thing is in my head, idk. i can say one thing though, these koni sports are weak shocks. i have a set of rear bilsteins in my closet that have a ton of miles on them and must be 10yrs old and they have more damping in them than the koni's right out of the box. if i put all my weight on the koni rear i can easily compress it, the bilstein i have to really push down to fully compress it and it comes right back up quick. i'd throw them in the rear but i have a feeling it will really ride like crap as these are so much stiffer. plus idk if its a good idea to run them in the rear and konis in the front, thoughts?
Loosen the rsb. Try OUTERMOST holes and report back.

Can also get the car corner balanced as suggested. That is important, especially when you are doing a bit of "mix and match".

Regards,
Jerry
 

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I have the same challenge, rear end has a pendulum effect. Gc coils 430f/380lbs rear, 13.5" front hight and 13.5" rear. I also have 12mm spacer front and 5mm rear (I think) h&r RAB AND wheel alignment was done but not corner balance. The rear comes around when going fast on banking. For example, any sharper turn in while going around banking causes the rear to simply swing out.

I will stiffen up the shocks.


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One cause for oversteer is the from the rear end getting light (too stiff in relation to the front). If your corner loads are correct try softening the rear sway bar. If this doesn't completely fix the issue try stiffening the front dampeners and softening the rear.


I have the same challenge, rear end has a pendulum effect. Gc coils 430f/380lbs rear, 13.5" front hight and 13.5" rear. I also have 12mm spacer front and 5mm rear (I think) h&r RAB AND wheel alignment was done but not corner balance. The rear comes around when going fast on banking. For example, any sharper turn in while going around banking causes the rear to simply swing out.

I will stiffen up the shocks.


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You should soften the rear end and try that first before you adjust the dampeners. Your rear suspension is too stiff in relation to the front. softening is the direction you need.
 

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You should soften the rear end and try that first before you adjust the dampeners. Your rear suspension is too stiff in relation to the front. softening is the direction you need.
Since I have the shelf in I stiffened up the dampening on the fronts another 1/4 turn to stiff. Lets see what happens next time I drive it.
 

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Discussion Starter #10
Does the oscillating oversteer occur while turn in one direction or both?


One cause for oversteer is the from the rear end getting light (too stiff in relation to the front). If your corner loads are correct try softening the rear sway bar. If this doesn't completely fix the issue try stiffening the front dampeners and softening the rear.
both i believe, just the majority of the turns i notice it on are left hand sweepers. originally the bar was on the middle holes, i moved them to the innermost ones. i will try the outer holes. im no expert when it comes to suspension/handling but i thought making the bar stiffer would reduce the body roll.
 

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both i believe, just the majority of the turns i notice it on are left hand sweepers. originally the bar was on the middle holes, i moved them to the innermost ones. i will try the outer holes. im no expert when it comes to suspension/handling but i thought making the bar stiffer would reduce the body roll.
It does, but it also prevents the suspension from being able to soak up bumps. The tires have less ability to work independently, so they tend to "skate" more over the tarmac. Don't worry about body roll so much, be more concerned about the tire staying in contact with the ground.

Regards,
Jerry
 
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both i believe, just the majority of the turns i notice it on are left hand sweepers. originally the bar was on the middle holes, i moved them to the innermost ones. i will try the outer holes. im no expert when it comes to suspension/handling but i thought making the bar stiffer would reduce the body roll.
Jerry is on the right path. Your alignment may well not be ideal, but your setup needs to be corrected first. Get the car corner balanced.

Also, you probably have the front too soft and the rear too stiff. The weight balance under braking is shifting forward to fast, and the rear end is getting light. As the rear end unloads the rear brakes become less effective. The rear of the car is now traveling faster and trying to over take the front.

something about which to think.
The Physics Of: Oversteer - Feature - Car and Driver


P.S. a softer rear end may also help at the drag strip. this will allow the rear to squat down and get planted faster.
http://www.m5board.com/vbulletin/e39-m5-e52-z8-discussion/28155-understeer-3.html
From Paul's Thread
 

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Discussion Starter #13
ok so i moved the links to the outer holes. i'll drive it tomorrow and report back. as i said before i can't believe how soft these konis are compared to bilsteins. i wish there was a strut(not coilover) that was a little stiffer than the konis but not as stiff as the billy's. or that you could adjust the compression damping on the konis also.
 

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ok so i moved the links to the outer holes. i'll drive it tomorrow and report back. as i said before i can't believe how soft these konis are compared to bilsteins. i wish there was a strut(not coilover) that was a little stiffer than the konis but not as stiff as the billy's. or that you could adjust the compression damping on the konis also.
You can buy dual adjustable Koni's if you wanted, im sure there are others that let you adjust both rebound and compression....

Are you sure everything is the rear suspension is tight with no play? I'd start by checking all the rear ball joints/arms/bushings/mounts/etc.
 

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Discussion Starter #16
You can buy dual adjustable Koni's if you wanted, im sure there are others that let you adjust both rebound and compression....

Are you sure everything is the rear suspension is tight with no play? I'd start by checking all the rear ball joints/arms/bushings/mounts/etc.
i have never seen a koni sport strut with compression damping adjustments. there is no play in any of the rear suspension.
 

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update, the car definitely has regained traction in the rear with the sway bar set to the outer holes.
:)

If still too much rear stiffness, your next "adjustment" is to unhook the rsb completely. If that helps, I would go back over my front setup, so the rsb, set to outer or middle, provides some help.

Not sure if you have a square setup, but if you do, it would be interesting to see how stock size wheels up front (with matching rubber) would help. I suspect it would......................

Regards,
Jerry
 

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Stiffing up the front shocks Made a difference, so it looks like stiffer front SB is necessary to balance out the rear bar.


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how come i installed my kwv3 went two clicks harder on the rebound all around my rear sway bar is set on the most inner and my beast handles like a rape date,
 
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