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Motorsports & Track Forum
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Old 02-24-2014, 12:49 PM   #1
ajai
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Long sweep oversteer

Whenever I do long sweep curve, the rear is very nervous.
It didn't really slide out, but it feels like it will snap anytime.
What's causing it?
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Old 02-24-2014, 01:46 PM   #2
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Old 02-24-2014, 01:53 PM   #3
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Sub'd for the graph up there
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Old 02-24-2014, 11:55 PM   #4
ajai
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Oversteer mid corner , is that my case?
But it's only on long kind straight sweep.
I had no problem at sharp or long corner,
Only at those straight but long curve.
its feel like the weight is all to the side, but the rear is more nervous.

I reduced soften the rear damper a bit, then it really will oversteer, tail slide right out at apex
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Old 02-25-2014, 10:08 AM   #5
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Quote:
Originally Posted by ajai View Post
I reduced soften the rear damper a bit, then it really will oversteer, tail slide right out at apex
Typically softening the rear and/or stiffening the front will induce understeer (i.e. remove some oversteer tendencies). That is very general as there are a lot of little things to consider which those graphs attempt to define. In general, you want o soften the rear or stiffen the front. Either one will provide the same benefit, it just depends on where you have the most adjustability.

Also, what is your tire setup?

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Old 02-25-2014, 01:00 PM   #6
ajai
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The funny thing is soften the rear made my car Oversteer, and not understeer.
It's opposite to the theory .
my setup
front 0 toe, -1.8 camber
Rear 1 toe in, -2camber

Front tire 30psi rear 33psi

front damper four clicks stiffer then rear
F 22/32, R 18/32

the rear end is never really step out , but just super nervous.
No confident
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Old 02-25-2014, 11:26 PM   #7
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Hard to say with so many variables, but you could have a few things:

* 4 clicks isn't enough of a difference with your dampers (some dampers may offer XX number of adjustments, but requires large changes to show differences)
* Is the car corner balanced? Could just be a balance issue with the suspension.
* You just may not be used to the amount of roll/lean the car has and you just need to build confidence
* Are you taking tire temps/pressures? With a higher rear pressure, you will be adding to the oversteer tendency (should equal out some if you are still staggered)

Personally, I found my E46 M3 an understeering pig with a mostly stock setup. You could always go with a larger front sway bar but it seems something else is more a miss with your setup.
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Old 02-26-2014, 10:47 AM   #8
ajai
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if four click is not enough , I should of Soften the rear more, since the front is very stiff for road now.
But as I tried, crazy oversteer,
buddy , as you mention about the tire pressure, this is a big question mark in my head.
Some say front low rear high will make understeer, and as you and some other day the opposite.
I assume you are right about corner balance, my truk is full of crap right now
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Old 02-26-2014, 02:18 PM   #9
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..., my truk is full of crap right now
Yeah... If there's a decent amount of weight bouncing around back there that could be all the difference in the world.
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Old 04-18-2014, 10:42 AM   #10
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I'd check your rear suspension for a bad shock mount or shock. Is it a left or right hander? If its a left hander...are you applying the gas smoothly?

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Old 04-26-2014, 12:26 PM   #11
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Rear control arm bushing failure? When mine were failing it manifested in fast turns, mostly on rippled/junk pavement.. Caused the car to latterally skip during extreme corners, otherwise just did not feel planted.

Another idea; are the swaybars properly setup? Endlinks are properly attached, bushing in good shape? In a long corner the swaybars are definitely being used; so any deflection or shaking in that system would definitely cause a nervous ride as well..
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Old 04-26-2014, 12:30 PM   #12
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I'd check your rear suspension for a bad shock mount or shock. Is it a left or right hander? If its a left hander...are you applying the gas smoothly?
I recently replaced a failed rear shock mount (did both anyway), they had begun to tare on the side facing the tire (instead of facing the speaker deck).

Symptoms were at their most extreme driving at highway speed on bad pavement. Driving with that failure required constant steering wheel correction to keep it in a straight line on undulating pavement.

Below 40 mph, the failure wasn't perceptible.. Although I think it was just a matter of time as the RSM continued to tare.
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