Setup steer-in versus traction
11-11-2011, 09:25 PM
Post: #1
Setup steer-in versus traction
Hi,

I'm looking for a setup that generates enough steer in-yaw and good traction at accelerating out of the corner.
I preffer a slight over-steered car at steer in.

I made my rear sway-bar adjustable.
At "hard" position I feel some increased yawing at steer-in but traction at corner exit when pushing the accelerator is Huh Huh
Massive wheelspin from the inner wheel.

Now, I dis-connected the rear Sway bar and this is my favourite setup so far.Steer in yaw is reduced and I feel diagonal roll but traction at the exit is much much better.
Off course I would like to have the swaybar to improve the steer-in.
How can I get both, traction and steer-in?
I was thinking about increasing spring rate in the rear.
What I see on the forum is that mainly all run way harder springs in the front than in the rear. It makes higher freq. in Front than Rear. Isn't this creating more understeer?

I'm not running on trackdays or circuits but on narrow (rally) roads in regularity events. So means, many thight low speed corners.

The front axle is not very responsive but I'm waiting to buy urethane bushings. and I will play around with the toe.

LSD is OE it's maybe OK for 50% only.
Any suggestions are welcome

my setup:

Front:
Camber -1-1.5 deg
Castor: OE
Toe 0
Spring around 4kg
Dampers: TRD blue???

Rear:
Sway bar none (at the moment)
Bilstein
spring around 3.7

Tires : Toyo T1R F 2.1 R 2.2
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11-11-2011, 09:49 PM
Post: #2
Setup steer-in versus traction
Simple rule: Assuming the rest of the car is ok: increase front spring rate untill you get the turn in and roll angle you need, then increase rear roll stiffness until you get the steady state balance you need.

Other guidelines:
Corner entry at the moment of turning the steering wheel = alignment (mostly toe) and brake bias
Corner entry towards apex and exit = dampers and springs
Apex and steady state = springs and anti roll bars.

How are your front tires wearing?
My bet would be to try more front spring and more front camber
HIgher freq in front is needed to be able to accelerate in a corner, at perfect 50-50 freq and 50-50 f/r weight you are using the tires 100% for cornering, this is impossible because the rears need to transmit power and overcome drag. The higher hp, the more front bias you can effectively use. For a stock car start at 55% front minimum.

AE86s suck at tight low speed corners because of the rear axle (binds due to inequal length linkages). You probably noticed the understeer that produces. Your only option is to go equal length and fast (edge of traction) or to slide the car through (slower).

Try and find out your current roll balance by driving a big circle somewhere and seeing which end lets loose first. Also a good chance to check tire temps and pressures.

A wheel to steer the front of the car
A pedal to steer the rear
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11-12-2011, 11:21 AM
Post: #3
Setup steer-in versus traction
Thanks for the reply.
I understand the front setting trials. I will do today...maybe
But the changes in the rear will dcerease traction at corner exit no?
So far, I feel the drop of traction way bigger than the improvement of the Rear end steer-in when I make a change. (I hope this sentence is clear ???)

I will play with Rear tire pressure since this will not change the lateral load transfer a lot so I might keep traction.

Just for my interest: Is anyone else running without rear sway bar?
I understand my driving conditions are not so common AE86 here (drift, track...) Cool Cool
So maybe I'm an exeption Wave Wave
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11-12-2011, 12:37 PM
Post: #4
Setup steer-in versus traction
There are lots of people running no rear swaybar on RWD solid axle cars. It saves some unsprung weight and allows for more droop travel (inner rear is contributing longer).

Simplest thing to try would be no rear swaybar and big front sway. See how that feels. Once you start getting too much understeer, try add some toe out to the front and throwing the car at the apex more. Cheapest two solutions to tight corner traction.

A wheel to steer the front of the car
A pedal to steer the rear
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11-12-2011, 08:34 PM
Post: #5
Setup steer-in versus traction
My friend is doing hillclimbs, so in a similar situation to your use.
He runs no rear sway, full coilover (very stiff) and slicks. He's doing quiet good in his class with that setup.
In high speed corners the front inner wheel is lifting off but due to the slicks he stays on track.

AE86 ex-daily
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11-15-2011, 11:46 AM
Post: #6
Setup steer-in versus traction
Bean Bandit Wrote:My friend is doing hillclimbs, so in a similar situation to your use.
He runs no rear sway, full coilover (very stiff) and slicks. He's doing quiet good in his class with that setup.
In high speed corners the front inner wheel is lifting off but due to the slicks he stays on track.

Aah, good to hear that. It confirms my feeling is not wrong.
The AE86 inner Front wheel lift I saw a lot in the 80's on the rallies. Maybe also no sway bar in the rear Smile

I increased the tire pressure to 2.4. It's better and still borderline ok in gravel parts.
I adjusted the toe also. Initially to 2mm out but I had sudden US in mid corner (allthough I expected higher CF due to toe out). 2mm toe in improved it. I guess the bushings are gone and I might have too much toe out when driving as NoHachi mentioned.
Next is camber increase....

THANKS Thumbs up! Thumbs up!
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