Re: Hypnotized on the web

[Robert Houk - SMCC WorkGroup Server Firmware <Robert.Houk@East.Sun.COM>]

At the risk of getting caught in the middle of a perfectly juicy
flame fest . . .

   [...]

   > A torsen hunts, it's designed to, ...

   No, there is no randomisation or search generation mechanism in a Torsen.
   It's a purely reactive device.

I get the feeling you're both correct, just using different terminology.
See below...

   > It will hunt until it finds
   > traction, even if it is constant, on a lake of ice, that would be a long time
   > wouldn't it?  The torsen doesn't know it's on that lake.  The locker doesn't
   > care.

   No.  If c/f is truly equal ('constant' is irrelevant) for all wheels,
   the Torsen will be in a steady state no matter what the input torque
   variation.

   > Bottom Line:  You think the Torsen is doing ALL the correct things for
   > traction.  My whole argument is that switch is too dumb to do ALL the correct
   > things for real world traction.

   It's _NOT_ a switch.  A switch has discrete states.  A Torsen can be in
   any one of an infinite number of states between its limits, and can
   move between states at a variety of speeds.  It _cannot_ move between
   states in zero time - inertia prevents this.  During the movement, it
   passes through all of the intermediate states.  It does not and cannot
   "switch".

For example, my trivial little office dictionary has a buncha definitions
for "switch", as in:

  1:	A thin flexible rod, stick, or twig, esp. one used for whipping

	Well, you're sure whipping each other up over this, but I don't
	think that's the right definition.

  5:	A device used to break or open an electric circuit or divert
	current from one conductor to another

	Or, generically, a "discrete" (typically "binary") choice.

	A torsen is an analog device with a "range" of outputs, unlike,
	say, a "Detroit Locker" which is either locked or not...

	"5" a torsen definitely is not.

  9:	A transference, or shift

	"9" a torsen would seem to be.

May I politely suggest "switch" is simply not an appropriate word to
use here...since noone agrees on what it means...

ditto "hunt" from above -- a torsen *will* "hunt" to the appropriate
state, and it is not in the least bit "random" in so doing...

   [...]

                                                            There are three
   Torsen ur-quattro owners on this list, all of whom have tried to recreate
   this problem.  There are three Torsen ur-quattro owners in Area K who've
   tried it, and one in Area E.  That's _seven_.

   It doesn't happen.  Null phenomenon.  No fault found.  Torsens went into
   thousands of cars starting in 1987.  They're still being put into cars.
   The driver's manuals don't mention "spider bites".  The high-performance
   driving courses that Audi run don't mention "spider bites".  Why?

Here, I would have to say "lack of proof is *NOT* disproof", merely
that you can't reproduce it with the available information. This could
equally well mean "it doesn't exist" *OR* "you don't know how to do it".

I've tracked down enough obscure problems to recognize that some 
awfully crazy and impossible problems *can* indeed exist if simply you
have the sufficiently right scenario.

For example, what if "his" torsen has a chipped/missing gear tooth
(or is in some other way "flawed", or just simply different)? You will
never be able to reproduce *his* observed behavior on *your* system.

A "real world" example -- my UrQ had a "run like shit" mode during
warmup when it was cold and damp (details deleted). Nobody else seemed
to have that problem. After *MUCH* grief and aggravation, a new ECU
fixed the problem. My problem was real, notwithstanding the inability
of *anyone* else to reproduce it on their cars.

					-RDH