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Old 11-16-2009, 11:29 PM   #1
Blown_xa
 
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Drives: Scion xA
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widening just the rear track width will cause your car to understeer more than is does already. You should keep it the same width front and rear if not wider in the front. Increasing track width over-all will make the car more stable, but also you are extending the leverage point of the suspension therefore softening your spring rate in a sense. If you understand suspension and handling characteristics and how to adjust them, then you can come up with a killer handling car.

I use 20mm spacers in the front and 10mm in the rear.
I set up my car for slight oversteer steady state.
Also in my set up to acheive that includes:
Progress Coil-overs with 200 pound springs in the rear, 450 in the front.
Progress rear sway, stock front sway (soon to be omitted)
-2.6 degree front camber, 0 toe
-1.1 degree rear camber, .40 degree toe in(per)-rear toe in helps with stability on high speed road coarses with short wheelbase, probably run less for auto cross.
Tires are everything, you can have $6000 coil-overs and a guy with stock suspension but with better tires will beat you...
I run Toyo R1R's 225 50 15's all around
28psi cold front
33psi cold rear

just suggestions but at least you have something to go by.
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Old 11-17-2009, 08:33 AM   #2
Tamago
 
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Quote:
Originally Posted by Blown_xa View Post
widening just the rear track width will cause your car to understeer more than is does already. You should keep it the same width front and rear if not wider in the front. Increasing track width over-all will make the car more stable, but also you are extending the leverage point of the suspension therefore softening your spring rate in a sense. If you understand suspension and handling characteristics and how to adjust them, then you can come up with a killer handling car.

I use 20mm spacers in the front and 10mm in the rear.
I set up my car for slight oversteer steady state.
Also in my set up to acheive that includes:
Progress Coil-overs with 200 pound springs in the rear, 450 in the front.
Progress rear sway, stock front sway (soon to be omitted)
-2.6 degree front camber, 0 toe
-1.1 degree rear camber, .40 degree toe in(per)-rear toe in helps with stability on high speed road coarses with short wheelbase, probably run less for auto cross.
Tires are everything, you can have $6000 coil-overs and a guy with stock suspension but with better tires will beat you...
I run Toyo R1R's 225 50 15's all around
28psi cold front
33psi cold rear

just suggestions but at least you have something to go by.

lol guys, haven't we already learned that a stiffer rear spring one of the easiest modifications to combat understeer?

your toe-in settings (which i'm guessing are FACTORY, you haven't done anything at all to the rear of the car) are excessive and will be detrimental to your turn-in.
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Old 11-17-2009, 07:29 PM   #3
Blown_xa
 
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Drives: Scion xA
Join Date: Oct 2009
Location: Virginia
Posts: 449
they are close to factory but I did adjust them. I use feeler gauges in between the hub and axle. These cars are a very short wheelbase, that changes what you may think. On our tC we run toe out in the rear on small tracks but it also has a huge Kognition rear spoiler to keep it stable. My car is set up well, I posted a couple of videos you can check out and kinda get a feel foer the balance of handling. Like I said, it has slight oversteer. And If I throw it into a turn the rear end kicks out contrary to what you say.
Here is a video from more than a year ago, same alignment spec but with 200 pound springs in the front. RTA practice, camera from a Porche GT3. I ran off line and turned in to fast to correct and that's all it took. btw this was 130whp stock motor
http://www.youtube.com/watch?v=_toT_...layer_embedded
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Last edited by Blown_xa; 11-17-2009 at 07:48 PM.
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