Re: Spider bites, those who have vs those who will

[Josh Pinkert <flush@us.net>]

At 06:50 PM 2/23/98 -0500, QSHIPQ@aol.com wrote:
>Dave writes:

The torsen topic came up a few months ago, and the *experts* didn't chime
in.  Now that they're here, maybe my experiences can be explained.  I used
to own a 90q and now own an A4q.  And I've driven a 4000q fairly hard years
ago(at 16 years old, I tended to push cars past their limit...).  That
means, in order, openlockable diffs, torsen center/lockable rear, and
torsen center/EDL.

>
>>2) both torsen and non-torsen stuggle when a wheel is lifted.
>
>Lock the rear on a non torsen, not a problem.  Given the chassis and spring
>rates we are talking about here, I don't see this as a real issue.  I've run
>some pretty high spring rates on audi awd cars (like 400+) and don't get
wheel
>lift.  I would argue that wheel lift is a suspension problem, not a torsen or
>non torsen one.  But your statement is correct.  Other than factory race
cars,
>how many pix do you see of a quattro on 3 wheels or less.
>

I've autocrossed my A4q a few times and was apparently picking up my inside
rear wheel.  Was I on the brakes?  I don't know...but the inside rear wheel
was still turning...slowly at the speed of the rest of the car.  Now it'd
probably take a ton of power and grip (which the stock continentals do not
have!) to pick up a front wheel.

>>3) a torsen "hunting" only happens when traction gets lost.  see point
>>(2) above.
>
>INCORRECT dave.  A torsen hunts with a change in relative driveshaft speed.
>That's all.  That doesn't necessarily require loss of traction for that to
>happen. The difference in front and rear track or slip angle is enough, so is
>throttle position.  You say it yourself with the WOT line is the only way to
>go, power slide out.  Why?  Cuz if you don't, that torsen hunt becomes a
>handful few can recover from. Wholy looking at point <2> above, I see you
>equating this with wheel lift.  The hunting torsen doesn't need wheel lift to

>bite.  Just momentary throttle lift is enough.  

Slip angle may be enough only if you've got a ton of oversteer.  On dry
pavement, only sticky race tires will achieve enough slip angle at
7/10-10/10 to make torsen do anything out of the ordinary.  

And on throttle lift...we're talking backpressure from the engine, ie
engine braking.  Lifting will upset the car regardless of torsen or
non-torsen.  We're talking about going from a balanced state (slight
throttle), right?  That'll shift the weight forward, causing the tail to
begin to rotate...on just about ANY car.  A torsen could get confused, but
I'd think it would shift the torque from engine braking to the front wheels
resulting in understeer.  But the torque from engine braking is nothing
compared to stepping on the gas.  At least this was the case with both the
90q and the A4q.

>  Driving a Torsen at 10/10ths+ has a lot of brown stained leather
>associated with it.  I advise not to get bitten, it ain't fun.  What you get
>is a lot of respect for exactly what a Torsen isn't.  Predictable.  When you
>are at the point of the bite, the last thing you want to happen, is have a
>hunting differential tripping up your technical and delicate q-dance.
>

Again, when autocrossing I've not had any un-predictable acts go on in my
torsen q.  Maybe the EDL helps tame it a bit...maybe not.  I don't think
it's as bad as you make it out to be.


--        
Josh Pinkert 
flush@us.net 
'98 A4q 2.8 
ISO '70-'73 or '78-'83 Porsche 911 
--