RE: Bites of dead horses, last post for me

[QSHIPQ@aol.com]

Dave E writes:
>errr, au contraire scott, there is considerable documentation which directly
>contradicts your view, from a variety of sources.  for example:

Uh, oh.  But I don't disagree with the below, just draw a different and 
blatently obvious (IMO) conclusion on what was written:

>i have a white paper from zexel which specifically mentions a range of
>chassis factors in the behaviour of the diff.  let me quote:
>"The ideal centre differential Torque Bias Ratio layout in the 4 operating
>modes is a function of vehicle dimensions (wheel base, track width, centre
>of gravity height, etc.), suspension elasto-kinematic design (stiffness
>front/rear, angular variations, etc) and engine torque characteristics for
>given road conditions.  Therefore the ideal design characteristics for a
>centre differential can be determined after a great deal of subjective
>vehicle tests.  The optimisation will be a compromise between different
>set-ups, depending on the surface conditions (dry asphalt, wet asphalt,
>snow, ice, etc)."i think that the text makes it pretty clear, don't you?

Absolutely positively clear Dave.  Reread:  "IDEAL"  Problem:  a) what is 
"given road conditions"?  What exaclty is the "optimization will be a 
compromise" mean in terms of u-o-u vs straight line traction?  and 2) if 
exactly the same torque split is used (the same device) which chassis are 
compromised and which aren't, in the audi lineup.  The above are the factors 
that affect the when, not the IF of inappropriate torque shift by the device. 
 Bottom line:  Compromises HAVE to be made to the device, cuz it can't 
perform optimally in all.  That's what the above says, always has.  Help?

>i also have a white paper from the boys at gmc who developed a mathematical
>model for the torsen with 6 (count 'em thats six) degrees of freedom.
>in your model scott, you've got 1 degree of freedom (i.e. if there's a
>torsen, there a bite).

Nature of the device, sorry, not my device, only my evaluation of it.  And 
Stan Chocholek's.  Not much freedom to play in a torsen car, sorry btdt.

>enough said.  as for your previous attempt to recreate history by stating
>that phil or myself had categorically denied the possibility of ill-defined
>chassis behaviour with the type 44 at the limit, i am endeavouring to take a
>charitable view....

If it happens in 1, the conditions only have to be right with the other 
chassis (reread your first paragraph).  You both denied it happens in some of 
the other chassis.  Hard case to make.  Think about it, if 56% of torque 
shifts in one chassis with the right matrix and the device is the same, it 
shifts that in every chassis with the right matrix.  You can't single one 
out, a device fooled is fooled.  I'm amazed that 78%front to 78% rear engine 
torque is controllable by any driver in ANY chassis, especially considering 
Blomqvists own comments below.

Blomqvist speaking of the torsen in rallying, per my interview in Rumford ME 
rally (see full content/context post in the archives 8-2-99):

"Armed with the following quote from Stig himself in the Nov '86 issue of 
Cars & Car Conversions - Can be found on page 127 of Audi Quattro Gold 
Portfolio, I was looking for some insight to the now, qlist, controversial 
quote: 
"...On the handling of the Sport, which was patently very difficult, whether 
judged from the 1984 passenger seat, or simply spectating, Blomqvist offered 
these illuminating insights: "It is much, much, better on the S1 than it was 
before.  The car goes where you steer!  No more understeer, oversteer, 
understeer as you do just one corner."   
"...
QSHIPQ - "Stig, one of the things I would like to talk to you about is a 
quote I found in an old magazine article almost 15 years ago regarding the 
Sport and the S1.  There seems to be some interesting debate on the use, more 
specifically the non use of the torsen center differential in racing, and 
specifically in the development of the Sports and the S1.  One of my projects 
is to try to talk to those involved in audis development of the torsen for 
race and street.  The most prominent quote I could find is from you (Stig's 
eyebrows raise - see above).  I know it's been many years, but could you 
please tell me if this quote was directed at the handling of the S1 because 
of the centre torsen?
STIG - (takes a minute or so to read the article, and the quote) - "Well, 
yes, the early S1 did have the torsen, but the drivers went to locked centre. 
 You see, the torsen was too twitchy in the loose, you couldn't control the 
turn..." (hand motions)  "The torsen, it pushes then it pulls, it upsets the 
car."  
QSHIPQ - "This created the understeer and oversteer you speak of?"  
STIG - "Yes." 
...

I'm already stepping out further than I promised myself on this dead horse, 
revived by one of the staunchest critics.  I'm happy to let Phil report on 
the arachnoid behaviors, Dave.  Your posts indicate your distinct 
misunderstanding of what was written about the device, and the physics of it. 
 No big deal, I'll drop this whole thing with your last word...

As always

Scott Justusson