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AWD mystery?


Evil Result
04-09-2005, 02:42 PM
Lets say for a moment we have an engine powerful enough to pull a wheelie with a 100% Torsen AWD system...Front center and rear differentials. now i under stand that if a wheel looses complete traction the torsen will act like an open differential, but of course appling some break helps resolve this issue and send power to the wheel with grip depending on the torque bias.

but the bigger problm now is the whole front end is off the ground, and without using any breaks the car would keep hopping up and down as it would gain traction in the front for a moment start to spin power would be sent to the rear wheels then the car would pull another wheelie but loose power because of the open front end scenario.

So we use a special break system to break the front end during a wheelie..but how would the torsen differentials act under this pseudo front grip especially the center differential? I'm shure the torque bias ratio's would have to be adjusted in some manner because of the larger breaking force of the front end.

and what would the drive train efficiency be with this excessive setup not to mention handling characteristics?

public
04-10-2005, 01:44 PM
If the front wheels are locked by the brakes the the center diff will cause the rpm to the rear wheels to increase. So I guess the vehicle speed would go up. I just want a car that will do a wheelie. Whatever happens to the diff it would be cool.

2.2 Straight six
04-10-2005, 02:54 PM
my friend brother built a very very powerful (vq30DETT) r32 skyline, it did a wheelie on the drag strip, it wheelied for about 10 metres then there were grining noises an the diff gears were shredded (quaiffe diff) too much torque = dead diff

duplox
04-10-2005, 09:13 PM
Lets say for a moment we have an engine powerful enough to pull a wheelie with a 100% Torsen AWD system...Front center and rear differentials. now i under stand that if a wheel looses complete traction the torsen will act like an open differential, but of course appling some break helps resolve this issue and send power to the wheel with grip depending on the torque bias.

but the bigger problm now is the whole front end is off the ground, and without using any breaks the car would keep hopping up and down as it would gain traction in the front for a moment start to spin power would be sent to the rear wheels then the car would pull another wheelie but loose power because of the open front end scenario.

So we use a special break system to break the front end during a wheelie..but how would the torsen differentials act under this pseudo front grip especially the center differential? I'm shure the torque bias ratio's would have to be adjusted in some manner because of the larger breaking force of the front end.

and what would the drive train efficiency be with this excessive setup not to mention handling characteristics?

If you have the traction to pull a wheelie, just remove all the AWD gear and make it RWD. The car should handle just as well(maybe not on snow/ice/water, but dry clean pavement it'll do just fine), and certainly launch better since you just lost a bunch of weight in the nose.

beef_bourito
04-12-2005, 07:14 PM
what about the diffs that can go from rwd to awd with the flick of a switch? shouldn't you be able to have it in rwd mode, pull a wheelie and then switch it back?

RandomTask
04-12-2005, 09:33 PM
Your scenario is generally why people have a locked center diff.

from www.torsen.com

"As mentioned above, the Torsen differential is a torque multiplier. The Torsen requires some type of resistance or friction in the system to function properly. A wheel in the air provides zero torque or friction on the system and as the Torsen multiplies the available torque, zero, by its TBR, the end result is still zero. In response to this, we developed the Torsen T-2R with pre-load to combat those wheel in the air situations. "

Generally torsen diffs are used in center diffs.

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