Hrrrm... aftermarket Quaife differentials?
02-26-2002, 02:36 PM
#14
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i agree, if it were on the front as the front outside tire lost traction
hte quaife would send the power to the insdie front wheel WITHOUT using brake power to redirect the torque...better IMO
02-26-2002, 02:45 PM
#15
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SCCA Audi has...
LSD front, VC center, Torsen rear... Hmm isn't it odd that it has a VC center and Audi keeps on saying how much a Torsen diff is superior?
Ok that was sarcastic folks. Sorry 'bout that.
If you don't believe me click the link.<ul><li><a href="http://www.speedvisionwc.com/competitors/vts/02-audi-s4.pdf">http://www.speedvisionwc.com/competitors/vts/02-audi-s4.pdf</a</li></ul>
Ok that was sarcastic folks. Sorry 'bout that.
If you don't believe me click the link.<ul><li><a href="http://www.speedvisionwc.com/competitors/vts/02-audi-s4.pdf">http://www.speedvisionwc.com/competitors/vts/02-audi-s4.pdf</a</li></ul>
02-26-2002, 02:53 PM
#16
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You are on the right track....
The biggest differential issue with these cars, for performance driving, is that there is too much power going to the front wheels. The problem that Jyoteen is having with power-on-corner-exit-understeer can most effectively by reduced by altering the bias ratio of the center diff. Once you are past the apex, and hard on the power, you're most traction-limiting wheel is the inside front. The next traction-limiting wheel is the outside front (not so much wheelspin, but remember the traction circle). This indicates that you have too much power going to the front axle, so increasing the bias ratio of the center Torsen will send more power to the rear. You'd be very surprised how effective this is. I was.
The rear diff needs to be addressed when you start getting high lateral g loads, and the inside rear wheel gets light or lifts off the ground. If you run slicks at the track, and a big rear swaybar, then there's a good chance you are getting enough g loading to lift that wheel. Most of it happens between turn in and the apex, before you get back on the throttle. When you do get back on the throttle hard, there's a chance that you can get wheelspin. This is when you need to change the open diff. A quaife will not work, however, because it is a torque biasing differential. A quaife multiplies torque, and since there isn't much torque resistance on the inside rear wheel, it won't do a very good job. A viscous, plate-type LSD is a much better solution here.
While using street tires, you'll probably never need the LSD in the rear, but you would definitely notice the benefit of the high bias center Torsen.
The rear diff needs to be addressed when you start getting high lateral g loads, and the inside rear wheel gets light or lifts off the ground. If you run slicks at the track, and a big rear swaybar, then there's a good chance you are getting enough g loading to lift that wheel. Most of it happens between turn in and the apex, before you get back on the throttle. When you do get back on the throttle hard, there's a chance that you can get wheelspin. This is when you need to change the open diff. A quaife will not work, however, because it is a torque biasing differential. A quaife multiplies torque, and since there isn't much torque resistance on the inside rear wheel, it won't do a very good job. A viscous, plate-type LSD is a much better solution here.
While using street tires, you'll probably never need the LSD in the rear, but you would definitely notice the benefit of the high bias center Torsen.
02-26-2002, 02:59 PM
#17
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Not quite right...
While the Champion cars are running a Viscous center diff, they are actually running an LSD in the rear, and a torque-sensing diff in the front.
Looks like the "front" and "rear" are reversed on that form.
Looks like the "front" and "rear" are reversed on that form.
02-26-2002, 03:00 PM
#18
Re: SCCA Audi has...
Actually, Champion has tried a variety of combinations of front/center/rear diffs. I don't know what they are using now, but at one time they had a modified 944 turbo front diff and locked center and rear diffs. They have experimented with locked center/Lsd rear, locked rear/torsen center/open front, Lsd front/locked center/Lsd rear, etc., etc.
They have put an extreme amount of time in getting their combination just right for them. Mike, the team manager at champion is a pretty sharp guy and he has some really wonderful people that work extrmeley hard at making things work.......good luck to them at Sebring.
Don Istook
They have put an extreme amount of time in getting their combination just right for them. Mike, the team manager at champion is a pretty sharp guy and he has some really wonderful people that work extrmeley hard at making things work.......good luck to them at Sebring.
Don Istook
