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Suspension question, Oversteer, under damped, or something else?

2K views 18 replies 7 participants last post by  m5 deamon 
#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?
 
#2 ·
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.
 
#3 ·
I would look at the tires and the differential.
 
#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?
 
#6 ·
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
 
#5 ·
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.
 
#8 · (Edited)
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.
 
#7 ·
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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#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.
 
#14 ·
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.
 
#17 ·
:)

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
 
#18 ·
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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#19 ·
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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