Re: Tshift comparos

[Stilian Elenkov <elenkovs@vtls.com>]

QSHIPQ wrote:
> 
> 
> Since we haven't really mastered torque transfer on accel, I'm hardly going to
> address the differences on braking. Not relevent yet.

As far as I know VC does not work very well while braking (I mean it
really sucks).
Try breaking into a corner with both rear wheels locked in sync cos the
VC sensed some Rotational
difference. Is that a good thing.
 
> 
> Not sure that statement is clear.  I read that the VC AWD system is the same
> animal as a torsen, or more so.  IOW, a VC has distinct advantages over a
> torsen in terms of chassis dynamics in a turn.  If that is the read, I totally
> agree.  And can handle more torque than a torsen as well.  And is sealed, and
> is a lifetime part.  Nothing touches.  Simple and dumb, beats dumb and dumber
> (tm).

I do not buy that at all. Torsen has proven to be very competitive in
racing  - Look at Lancia Delta and the UrQ that use Torsen vs the
competition using VC.  If torsen was so bad nobody would use it
considering it is more expensive. Also VC has logarithmic action and is
greatly affected by temperature. Imagine an exhaust leak close to the
rear diff and constant lock - now that will be pretty in turns.


> 
> VC do require rotational differences to lock.  Some torsen proponents would
> like us to believe that is a bad thing.  Retaining the inherent chassis
> character in a turn, makes a VC more of a good thing than any rotational
> shortcomings.  We could certainly extend the argument to say that the torsen
> is quicker to react to slip and relative slip than a VC.  Good or bad?

Torsen does not detect slip (which is rotational difference) that is the
job of VC
after the slip has occurred ( ~ 0.5 - 1.0) seconds AFTER the slip
depending on the 
setup for racing apps sometimes even later. Torsen does not allow
"theoretically" the slip to 
occur while allowing rotational differences during braking and
cornering. That is what the Torsen white paper states. If you do not
agree with it prove their data wrong with good enough sample pool
(statistically significant). Chassis dynamics is all nice and pleasant,
but VC offers more disadvantages than torsen according to european
racing statistics (results I mean).

> 
> I really believe that the argument is in terms of chassis dynamics in a turn.
> There a torsen has many faults, the least of which is slip angle.  The
> confusion this thread has created centers here.  This is the first time Dave
> E. has admitted that a torsen can be fooled in a turn.  Given that, it's a
> 'when', not an 'if', in terms of chassis dynamics in a turn.  It's inherent in
> the design of every audi chassis with a torsen.  If a torsen can be fooled, so
> can the chassis it's attached to.  All you need are the right set of
> variables.
> 

The page  http://www.rallycars.com/Cars/4wd_turbo_cars.html  that I
pointed you to has a lot of links proving that racing cars using torsens
are winning vs VC equipped competitors, now if that is not good enough
proof that torsen works in 10/10th I do not know what is. BTCC A4q,
rally UrQ, and Lancia Delta are some of the prime examples of cars that
dominated while using torsens. Now that is a fact, that no chassis
dynamics and slip angels can argue with. Torsen might have some
weaknesses, but none of the above mentioned teams complained about it,
and honestly I do trust their experience most. If you detest torsen so
much why do you drive a torsen car? Get a Subaru WRX, I hear they are
great cars.


> Scott Justusson

Stilian Elenkov