# Physics is....

```>btw, this 7/10's thing is a complete misnomer.  as we've seen the torsen
>handles wheel lift better than the locker.  so what do you call wheel
>lift - 5/10's?  i prefer to think of your case as the 0.1% case...

Wheel lift is 'somewhere' beyond 7/10ths, but I would note Jeff's point that
'tenths' is relative to the driver....   You prefer to think of my case as .1,
and statistically you might argue so, however, that doesn't negate the physics
of what is happening, only the outcome.  You have Max Tshift, without wheel
lift.  So the physics is there, doesn't mean that physics translates into a
bite.  Back to my accident example.  "Significance" of Tshift Max
exponentially increases with a decrease in cf.  That can be at 5/10ths or
less.

>scott, when the (rear for example) is slipping as you describe, then it
>is describing an arc (by definition).  this is a pretty radical
>cornering attitude, by definiton (aka handbrake turn)...

No, a handbrake can be applied with NO change in arc, so I don't go there with
you.  The question is, in terms of an absolute traction world, is applying the
handbrake going to shift torque.  I argue yes, regardless of slip angle.
LESS than a wheel lift.  You must understand the argument you are making.  If
no wheel lift is 'radical', what is wheel lift, 'more radical'?  By
definition.

>another thing which i've gone on about is that the torsen is responsible
>in the ur-q for a major change in the balance of the car in the 'mb' and
>'rr' models, towards one which is much more neutral in it's balance.
>this is, as you descibe, because of the fact that in 'normal' cornering,
>the torque is biased towards the rear, due to the slip angle thing
>happening at the front.
NOT necessarily.  Remember a normal corner, center torsen allows for some slip
between f & r.  By the definition of the center torsen, 'significant' is
defined as any more than 22% torque/speed differential.  So 'normal' cornering
may not be affected.

>this improves front-end steering 'bite' and of
>course, raises the understeering limits of the chassis.  a good thing.
>big time.  makes the car more chuckable and more nimble.
I dont' go here with you.

You are addressing a LOT of variables in your effort to KISS.  Unfortunately,
the physics standpoint shows that those variables change, and so does the
torsen action in relation to them.  We can establish models that can show
significance of the Tshift, when you plug that into the real world of changing
cf (same cf all 4, KISS), that Tshift is no longer a constant, the signifcance
of it isn't either.  The problem as I see it, is more of 'predictability' and
control, than identification.   I believe to know WHAT is happening, not how
to prevent or control it.

Scott Justusson

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