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Re: Torsens par avion

In a message dated 97-01-02 17:14:50 EST, you write:

<< wrt torsen, the thread had sort of died but your mail made me think that
 just make it clear that in my experience the presence of a torsen centre
 diff does not prevent or eliminate the ability of the vehicle to execute 
 4-wheel drifts as some have suggested.  don't forget that with the
 torsen you always have a minimum of 25% power to the least tractive
Four wheel drifts, IMO, can be done in ANY vehicle, throttle on oversteer not
necessarily so...  I have not driven an S2 as of yet, but have driven the N/A
version of the 90cq, and found throttle on understeer just as prevelent....
 I'm not sure your 25% assumption to be true....  What I have found is that
the torsen tends to send more power to the front drive wheels than the rear
when in low cf conditions....  That creates inherent understeer, and have not
driven a torsen audi yet that has addressed that phenomenon....  Can it be
done with suspension mods, I suppose, but a challenge to the best of
designers (go for it jeff)..  My thinking is that a torsen "hunts" within
it's design perameters, and that creates a huge engineering nightmare when
applying oversteer suspension design to a floating "constant"....  Another
reason why, I believe that a fixed 50/50 diff gives you more control than a
"hunting" torsen diff....  

When you speak of oversteer quickly, dave, esp in gravel (and assure you it's
just as prevalent in snow or other low cf), that really is a torsen vs
throttle input problem.... You are trying to control understeer by throttle
on drift, but the torsen doesn't cooperate with your foot when you lift the
throttle to induce Lift Throttle Oversteer....  Instead what happens is you
get Lift  part throttle torsen split to rear, which tends to spin ya in a big
way....  At neutral throttle you get understeer, at full throttle you get
understeer, albeit very easy to drift, but my opinion is that your lift
throttle induces immediate oversteer, and I come from a prorally background,
it's immediacy caught me more than once in a torsen q car.....  I know this
is why none of the q race cars used a torsen center, a fixed point will beat
a hunting one any day....

I raced an A1 scirocco in Open Class, and find torsens just as easy to drift
as a front driver, until the torsen starts hunting....  The easiest part of
fwd was a late entry, oversteer to the apex and power drift out, exactly what
a torsen should do ...  Buffum used this technique with the Urq rally cars
(locked center), it's in his book....  The problem is that torsens don't have
a "true" lift throttle oversteer, or even understeer for that matter, either
of which would be most predictable.....  It wavers on your GOG, traction,
throttle  and torsen lock at the time you need to lift.....  
 both my audi's love 4 wheel drifts and are perfectly predictable
 under these conditions.  i usually do this sort of thing when the road is
 wet and traffic minimal and i have no passengers. the exit of a wet
 round-about is ideal (as phil has suggested i think). the same thing is
 perfectable possible on gravel and is a real buzz.  however both audi's
 on gravel with their wide tyres can get a bit of a handfull.  when they
 they tend to do so fast and you need to catch them early to avoid using up a
 lot of road bringing them under control
>>>>>>......  A mild understatement IMO....  Remember, drifting is really not
an oversteer condition, it's more an understeer condition, however
predictable....  Oversteering fast, I agree, catching it early, well, you
better be really good, cuz it happens SO fast you need to make decisions on
waiting forever for the throttle on understeer to reestablish itself (no S2's
on this side of the pond), or think about taking the spin and catching on the
360....  Either of which takes some serious genatalia, I assure you, btdt....
l (mind you not as bad as an m3 under
 the same conditions)...
  >>  Not sure I agree with that, and I drove one at a q club even in the
rain to disprove that exact idea,  but best leave the M3 for another

Still in search of the why with torsens myself......