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Re: Testimonials

In a message dated 98-04-05 16:34:38 EDT, you write:

<< You've taken a component, whose performance has been explained to us
 >all in a very loose and generally descriptive way, and you've
> extrapolated the description of its performance into a disaster
> scenario.
That would indicate that you agree that Tshift happens, just that it has no
effect on the chassis in under any circumstances.  Again, a subjective
argument.  Given Tshift at all, a tough one to make sir.  You've made it.  Few
follow it.  I can show by physics that slip angle is traction to a torsen
center.  That has components of disaster, by definition.  The scenario, is
just my btdt.  And just not yours, no big deal.  Flat doesn't happen?  That's
a big statement, with all due respect to your driving prowess sir.
> a) I am very far from convinced that the description of Torsen
 >   operation so far available to us is comprehensive.
Did you visit the web site that Jeff put the paper on? Is there something you
need help with?  You are far from convinced?  Well, a few of us are convinced
by that same documentation (from the horse) that the operation is VERY

> b) We have, as far as I am aware, no _comprehensive_ description
>    of the Torsen implementation used by Audi.  We seem to have
>    the torque split ranges - but we have no information on, e.g.,
>    the moments of inertia in the slewing mechanism.  To assert that
>    the device can switch in zero time, based on this input, seems
>    to me unsupportable.
We have exactly the comprehensive description of the implementation used by
Audi.  Specifically it is 22/78/78/22.  Don't make this too complicated.  The
device switches before wheel spin, that is not zero time, but certainly a
fraction of a second.  A VC can 'switch' torque in less than a full revolution
of a driveshaft.  Since a "torque sensing" 'switches' before speed
differential, that would indicate to me that you are not thinking this through
very far in terms of time.  Or do you refer to chassis dynamics not torsen
> c) You have generalised a Type 44 observation, which seems not to have
   > been made under ideal conditions, to all Torsens everywhere.  Dave
>   and I have repeatedly told you that this effect is absent on the
>    ur-quattro.  Period.  It flat doesn't happen.
Yup, and you must be THE expert to make such a strong testimonial.  You
haven't admitted to having it happen on a 44 chassis.  So, it happens on one
and not the other?  Why?  What part of physics changes between the two
chassis?  Think about what you are arguing Phil.
> d) There is _NO_ (i.e., not a single scrap anywhere) documentation
 >   supporting this putative aspect of Torsen behaviour.  Gleason haven't
 >   heard of it, Audi haven't heard of it, the UK quattro Owners Club
 >   hasn't heard of it ...
We all must be nuts here.  By physics I can explain Tshift.  Are you arguing
Tshift doesn't happen or that the chassis dynamics of Tshift has been
experienced?  If the latter, and given the former, are you sure about the
claim?  Gleason hasn't heard of it, neither has Audi?  Really, so you must
have done some homework.  Care to share some specifics of that testimonial
> Physics is not some postulated theory based on some hypothesis of how
 >something _might_ work.  Physics is how things _do_ work.  In the field.
> Reproducible.  Measurable.  Objective.
Tshift is objective.  You pick your argument well Phil.  A torsen is a
traction device, physics apply.  The physics of relative and rear slip angle
of tire rotation do to.  Also physics argument.  Reproducable?  Plenty of
folks here would love to have you come be taught.  Measureable?  Don't need
that, have it on the spreadsheet, defined by the split.  Objective.  Well, "it
doesn't happen cuz I said so" seems somewhat more subjective than my
presentations to date.  And I can explain your non event with my presentation.
Unfortunately, subjectively you can't, and objectively you haven't.  
 >Your ideas are not physics - they are speculation.  If you have had a
> problem of the nature you describe, it was _not_ a generic design
> weakness of the Torsen.  It was, perhaps, a bad Torsen - or something
> else.  But I've thrashed mine through the rain of the last few days
> here, and the effect you describe just flat out doesn't happen.
Phil, please.  What is the difference between a center torsen and a rear or
front torsen.  Slip angle is constant in the rwd and fwd, a variable in the
center.  What was changed in the physical design to accomodate that.  Nothing.
So, slip angle and relative slip angles are not only constant to a center
torsen, but are absolute traction variables.  Why?  Cuz that's the definition
of a rwd/fwd torsen.  What has changed?  Think Phil.  Now, you, as an "expert"
say it "flat doesn't happen".  Me, as a "goofball", says it "does in the right
circumstances, here's why, the math and physics of a Torsen center".  "Scott,
'expert' Phil says it flat doesn't happen cuz he hasn't had it happen to him,
what's up?"  Scott - " Well with all due respect to the MB expert, the physics
would indicate, and the statistical data would support that he hasn't had the
right circumstances to have it happen to him.  I have no problem with his or
anyone elses claim that it 'hasn't' happened to them. "  Uh, well Mr. Phil,
what's with that? 
 >And _THAT_ is physics.
Doesn't happen cuz it hasn't to you is a subjective argument based on YOUR
expert testimony.  I question the testimony before the physics, that's just me

Phil, you've tried to make your point on Torsen centers.  I think I've made
mine.  You aren't impressed with my math or my presentation of the physics of
a Center Torsen.  Not sure why, other than it might be pointing at audi,
heretical talk. You are reiterating expert testimony, not arguing physics.
Only indicating that the physics is right, but that there is no effect of that
physics on chassis dynamics.  Please correct my understanding phil.  A few of
us question that, based on physics.  Sorry dude.  

Hey how bout those MB numbers, I'll do the math for ya.

Are you sure they didn't hack up something when they "fixed" your car?  I
sense a bad day here.

Scott Justusson