Subaru Enthusiasts Car Club of the Sierras - View Single Post - What would a front limited slip differential do for a WRX?

Dean · 2004-09-21, 07:29 PM

Fearing that Gary will chime in and crush anything I say, I will none the less comment
I guess teh answer starts with it all depends...

A perfect LSD would be electronically controlled tied to actual ground speed at each corner and steering angle... Anything else is compromise.

Since a mechanical LSD can't know what the steering angle is, it can't know how much to let the wheels slip when you actually want to turn as compared to when a wheel is actually slipping.

In my experience with Audis, front LSDs can actually increase understeer. Matching all 3 differentials with the suspension is a huge challenge.

As you can tell from Gary's list of differentials for his USTCC car, the diff configuration may vary by course, and conditions...

This complexity is probably why none of the manufacturers I am aware of ship an AWD car with three LSDs, and IIRC I am only aware of one Audi that I beieve had a front LSD, and an open rear. I realize this didn't help much, but it is a really complex question.

2004-09-21, 07:29 PM	#2
Dean Señor Cheap Bastarde Real Name: Dean Join Date: May 2003 Location: $99 Tire Store Posts: 9,294 Car: $.04 STI Class: Fast,Cheap & Reliable=STI Deal, did somebody say Deal? Oh, Dean, yeah that's me.	Fearing that Gary will chime in and crush anything I say, I will none the less comment I guess teh answer starts with it all depends... A perfect LSD would be electronically controlled tied to actual ground speed at each corner and steering angle... Anything else is compromise. Since a mechanical LSD can't know what the steering angle is, it can't know how much to let the wheels slip when you actually want to turn as compared to when a wheel is actually slipping. In my experience with Audis, front LSDs can actually increase understeer. Matching all 3 differentials with the suspension is a huge challenge. As you can tell from Gary's list of differentials for his USTCC car, the diff configuration may vary by course, and conditions... This complexity is probably why none of the manufacturers I am aware of ship an AWD car with three LSDs, and IIRC I am only aware of one Audi that I beieve had a front LSD, and an open rear. I realize this didn't help much, but it is a really complex question. __________________ I am a Commodore PET --- Now get off my lawn you kids...