[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: Torsen 201
no scott this is simply not true. you do not understand how a locked differential works. once it is locked, the differential *because* it does not allow shaft speed differences, cannot control torque distributed to either shaft. so torque is entirely dependent upon tractive forces (front/rear slip). think of a "locker" quattro with the front driveshaft disconected - all torque will go to the back. with the front on ice, *most* of the torque will go to the back. ditto in turns where the forced slip front/rear caused by vehicle dynamics (weight transfers, etc) cause the same effects. freemans paper "4wd powertrain models" describes the torque proportioning effects of a locked centre diff in detail, including showing what happens on traction loss at the rear sending torque to the front. ditto jeff daniels book which i've referenced before... because you do not grasp these points, you fail to understand the similarities between the torsen and the locker. and hence why 2 people on the list can experience the spider bite in locker quattros. dave '95 rs2 '90 ur-q '88 mb 2.3-16 -----Original Message----- Date: Tue, 2 Nov 1999 10:16:26 EST From: QSHIPQ@aol.com Subject: RE: Torsen 201 Dave writes: >i have stated (again, and again, and again), that both the locked >differential and the torsen are torque *proportioning* devices. the methods t>hat they use to proportion torque are of course, entirely different. as i >have also stated, the torsen uses internal friction (worm gears) to resist >output shaft speed differences in order to allow a torque difference between >those shafts. the locker just locks the shafts together. the effect in both >cases is exactly the same. No, not exactly. What you describe above, means that a locker *can't* resist output speed shaft differences. Physically it's impossible. I think you need to spend more time on this to figure out what that means in a turn. There is no friction or *allowance* for one shaft to rotate faster than the other in a locker. The effect in both cases is exactly NOT the same. You can *only* argue this in a straight line acceleration with no traction variable. >both output shafts are locked together which >allows torque to be apportioned according to tractive forces front and rear. >the torsen continues this behaviour until it reaches a pre-determined torque >proportioning limit (the bias ratio), at which point it allows output shaft >speed differences while holding the bias ratio of torque. I say it happens before the bias ratio. A .2% forced slip between axles quoted in 885140 with a 62r/38f would be documentation of that. How much forced slip between axles does a locker have?
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