Re: where's that torsen silver stake......

[Dave Eaton <dave.eaton@minedu.govt.nz>]

scott, lets not start this again.  at least not until we have real facts...

it's not *physics* yet, there are *far* too many unknowns.  thanks geoff
jenkins, for your lucid explanation of this.  i will attempt to fill in some
more...

1) scott, you base the *whole* of your case on btdt, and 1 sentence in the
gleeson article (aka the 'weasle words' of section 5.2).  both jeff and i are
attempting to get dialogue with the gleeson folks to clarify a hat-full of
things, to fill in some of the blanks.

2) your confident assertion that you are "arguing physics", and the rest of us
aren't is bollocks.  what you *have* done, is to present a case full of a whole
lot of assumptions, none of which we can verify with science (aka measurement,
observation, replication).  your assumptions (from memory):

. the behavour of a type 44/torsen executing under/over/understeer through a
corner is explained by the behaviour of the torsen alone (i don't doubt that
this happend btw, see below).
. the centre torsen splits torque at the bias ratio when the car is cornering.
. slip angle is traction to a torsen centre diff 

you also state that the gleeson paper is some sort of bible, where in reality,
it clearly says *very* little on the point on which we're arguing.  there are a
whole lot of things which are not covered, which we are attempting to get
clarified (for instance, it spends only 1 paragraph covering the torsen in a
centre diff application).

some of your other assumptions (made quite confidently btw) have proved to be
wrong before eg. because audi knew about the spider bite, they never raced, or
rallyed with the torsen centre.  they clearly did, and successfully, despite
the 'physics' of the spider bite.

3)you have *no* information on the implemetation of the torsen in the audi
chassis.  you don't even know whether the implementation in the type 44 is
*different* from the ur-q, the rs2, and the later cars.  do you?  it clearly is
btw, as the bias ratio has changed.  as you well know, most of the gleeson
article is an attempt to model the theoritical basis of the operation of the
diff, particluarly with regard the modelling of torque through the diff.  it is
not an explanation (and beleive me, i'd love one), of the operation of the diff
under cornering.  in the whole article, there is precious little about this
thing which is the whole basis of the "spider bite".

4) your case, when studied, makes me wonder how my cars stay on the road at
all.  the fact that they *do*, while doing the things i expect, indicates that
there are a number of *other* factors at play.  none of which we (me, you, us)
understand.  the fact is, and with your "spider bite" case in mind, both my
cars have tracked truely without bite despite my best efforts at provocation
(see previous posts of btdt).  btw, i've been sepnding the last week with the
rs2 and gravel (coromandel) roads.  low traction, high intertial moments, and
lots of fun (big time oversteer), but no bites (meaning, oversteer, back on the
power, back into line, lots of fun, and no drama).

5) i'm not dis-regarding your btdt (in a type 44 w/torsen).  please respect
others who have similar btdt (without the type 44).

i do get annoyed when you claim the "physics" high ground, when all i've seen
is a few formula based on the assumptions above, and *nothing* out of the
gleeson paper.  btw, i've also posted formula which show that the torsen is
much better than the locker when wheel lift occurs which, to me, is still worst
case....

one other nit, you keep telling us that a vc switches torque.  it does no such
thing.  it senses (switches) rotational speed.  you state that a (unnamed) vc
can switch torque [sic] in "less than one revolution".  i'd love to hear more
information on this?

lets continue this off-line, when we have more information..

as i've said before scott, a beer awaits, and a couple of cars to drive
whenever you make it to godzone...

dave
'95 rs2
'90 ur-q

>------------------------------
>
>Date: Sun, 5 Apr 1998 15:41:11 EDT
>From: QSHIPQ <QSHIPQ@aol.com>
>Subject: Dead duds
>
>Hey Phil:
>It's physics, you want to deny it, explain how it's NOT physics.  So far you
>have passionately argued to date it hasn't happened to you.  Doesn't change
>physics.  Not sure that we give so much credence to your "experience" that we
>are ready to flat deny physics.  I've presented btdt, a review of the lit from
>Gleason, and worked through the basics of physics and math to show what is
>happening.  Your expert testimony aside, what exactly are you saying, Phil?
>
>Present a physics argument that "indicates" I'm wrong, happy to correct ALL
>past posts.  This is "bad day" kinda flames here, happy to give you that
>benefit of the doubt.  Your subjective evaluation of physics is somewhat
>amusing, but really wasting bandwidth on an interesting phenomenon.   When you
>are ready to argue physics, please bring up the torsen thread again.  Still
>haven't seen those HP/Torque numbers you promised on the MB either.  
>
>Physics isn't personal, neither is the center torsen.  
>
>Scott Justusson
>
>------------------------------