Alpha6-27Tango(jeff)

This may seem like a stupid question, but I read that the "Torsen" system is a torque-sensitive electronically-controlled differentials between the front and rear tires. If it's electronically controlled, then can it change the power distribution between the front and rear? I searched for other posts on this, but didn't find much.

Wir fahr'n auf der Autobahn

This is the device "between the axles." Our cars are able to bias up to 66% of torque linearly front or back. Normally, the ratio is 50/50. The front and rear axles have open differentials with Audi's version of traction control called EDL in concert with the ESP stability control system.<ul><li><a href="http://www.torsen.com/products/T-1.htm">Torsen diff</a></li></ul>

April

to detect wheelspin and slow the spinning wheel while directing power to other wheels. Bias is usually 50/50 front to rear. With Quattro IV, up to 75% of power can be shunted front to rear, and up to 67% to any one wheel. Some older versions of Torsen based Quattro systems could send up to 78% of power to the front or rear, but didn't have the tricky electronic diffs of QTR IV. The electronic diffs operate up to 55mph in a QTR car, and around 45 in a Front Trak car. The function then disengages to prevent brake pad meltdown.

All types of VAG AWD systems:

http://www.daniil.dds.nl/skoda/vag-4wd-types.html<ul><li><a href="http://www.fortunecity.com/silverstone/lancia/58/technical_school/traction/tech_traction_4wd_2.htm">Other types of AWD</a></li></ul>

Alpha6-27Tango(jeff)

Thanks guys (gals). Great responses.

skidmark

erential can only tranfer 50% of power it receives to either of it's axles. if one of the axles starts slipping it drops even more. that's where the edl comes in, it brakes to transfer torque, but is also wasting torque in braking to transfer torque to other side of differential.

i don't know if this makes any sense to you, but i think you can only transfer 33% of torque to any wheel.

April

figure for max front to rear power distribution many places. What I recall is that if you have 3 tires on glare ice (no traction), the EDL absorbs 33% of available power in braking the wheels with no grip (it doesn't completely halt them), while the remainder gets channeled to the wheel with grip. If I can find my old workbook from that class, I'll scan it for you.

skidmark

and since it can't apply 100% to both, best it can do is 50% split to each axle if i am understanding correctly. and 50% of 66% from center differential(i thought we have a 2 to 1 bias torsen) is 33% to a tire.

i like to see info if you have it. i have seen lots of people say the same thing you have but no explanation of how.

from my figures if you used all torsen differentials(front,rear,and center) and all where 4 to 1 bias(transfer up to 80%) you could transfer 64% of torque to any wheel.<ul><li><a href="http://auto.howstuffworks.com/differential6.htm">http://auto.howstuffworks.com/differential6.htm</a</li></ul>