RE: Torsen II

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

this can all get lost in theoritical situations, so (and to save
bandwidth), i will re-iterate my main points...

1) non-torsen cars understeer more because they are unable to deliver
any *less* than 50% of torque to the front which overloads the wheels
already struggling to cope with cornering and braking.  not a good
thing.

2) both torsen and non-torsen stuggle when a wheel is lifted.

3) a torsen "hunting" only happens when traction gets lost.  see point
(2) above.

4) most of the manouevers of which we speak are done with power on.
certainly if you are attempting to power slide a ur-q or rs2 by
modulating the power, you'd better be wearing nappies.

in my experience, i have had the rs2/ur-q and my old s2 understeering
through a corner (too high entry speed, too much mower too soon), and
have had an oversteering twitch on entry to a corner (brakes).  but
usually, i'm hard on the power through the corner and the car is flat
and fast.  big grin factor.  no nappies.

btw, with regard to your point about racing cars and awd; there are no
circuit cars still racing with awd afaik.  we are all unsure as to what
technology audi used in the btcc cars, but the sugestion has been no
diff at all.

wrc rally cars are all using active centre diffs and have been for a
couple of years.  ditto the old fia class 1 super cars.  an active diff
is (by definition) going to change the torque distribution
characteristics of the car through the cars cornering manouevers.  is it
quicker?  you bet.

other thing i don't know is how the torsen handles in the "hp
challenged" applications of which you speak.  i should book myself a
drive i guess.  hp can cover up a lot of stuff ;-)

good discussion.  beats mustangs, now all we need is some anti-grouch
pills for rick :-)

dave
'95 rs2
'90 ur-q


>-----Original Message-----
>From:	QSHIPQ@aol.com [SMTP:QSHIPQ@aol.com]
>Sent:	Tuesday, February 24, 1998 3:41 AM
>To:	David Eaton
>Cc:	quattro@coimbra.ans.net
>Subject:	Torsen II
>
>Dave Eaton writes:
>
>>well scott, your explanation seems to perfectly explain the cornering
>>posture with the centre diff locked as well as torsen....
>
>Not exactly Dave.  I will follow you point by point.  A hunting differential
>will give different corner characteristics AS you drive thru the turn.  A
>locked differential will give you a constant "character" as you drive thru
>the
>turn.  A torsen center behaves like an fwd car, I raced an fwd car in
>ProRally, and drive the torsens that way too.  There is an EXACT reason why
>no
>race cars (period) use a torsen center.  A question to ask your mentor (and
>my
>hero) Herr Rorhl next time you speak...  One needs to wonder why all the race
>cars use a fixed diff split, in fact, audi used them (Walter included), tho
>somewhat varied the fix to conditions (60/40 to 70/30) in all their races as
>well.
>
>...
>
>