RE: open diffs at the limit.

[David Eaton <david.eaton@computerland.co.nz>]

actually glen, the point was that with the locked centre, tshift(max) is
100% of torque (to the rear axle) and so is worse than tshift(max) with
the torsen which is 70%.  upon regaining traction, you get tshift
forward again, etc.  for example, given 200 lb ft and lifted inside
front wheel,

locked centre: tshift (to rear) 100 lb ft, torque at front 0 lb ft.
torsen: tshift to rear 40 lb ft, torque at front 60 lb ft (dictated by
the bias ratio)

traction restored:
locked centre:tshift to front 100 lb ft, torque at front 100 lb ft.
torsen: tshift to front 40 lb ft, torque at front 100 lb ft.

so the 'spider bite' is much less (better) with the torsen, than with
the locked centre...

dave
'95 rs2
'90 ur-q


>-----Original Message-----
>From:	quattro [SMTP:quattro@acacianet.com]
>Sent:	Tuesday, March 10, 1998 7:54 AM
>To:	David Eaton; 'quattro@coimbra.ans.net'
>Subject:	RE: open diffs at the limit.
>
>>no dave,  we've lost traction at [either] axle.  same scenario as scott
>>proposed with the torsen....
>
>>agree with your conclusions about the open centre diff, but you 'lose'
>>an axle with the centre diff locked and you might be sending 50% of
>>torque that way, but none is getting to the ground.  the torsen is
>>sending (wasting) 30% of it's torque, while the generation 1 setup is
>>wasting 50%.  win for the torsen.
>
>Actually, with a traditional mechanical locking centre diff and one axle with
>no traction (both front -OR- both rear wheels have no traction) then 100% of
>the
>torque will be directed by the locked diff to the axle with the traction and
>0%
>torque directed to the axle with no traction..
>
>-glen
>
>