more "Care to Comment" -> differential t...

Tue Apr 9 23:41:08 EDT 2002

Quite the contrary Taka, the "Variable Torque Transmission" was to debut in
the sport quattro.  Too many rally drivers hated it, so in homogolation, it
was decided to go with what was IN the car most often, locked center (audi
was rightly pretty paranoid at this point, since Lancia was watching homog
violations like a hawk - it worked on the audi unhomoged air flaps for the
removed hi beams in the A2).  Walter Rohrl was "rumored" to have used it in
San Remo in 1985, but that car was interestingly destroyed by audi AG.

In my interview with Stig Blomqvist on the torsen center.  "It was too
unpredictable in the loose, it would push then pull you thru turn".  He is
also one of the few drivers that actually has published objections to the
device during the rally years.  Everyone else didn't say anything, just
didn't use it.  WR in 1985 is one of the few unconfirmed rumored uses.  I
will freely admit, of all the WRC rallies, San Remo was the worst wrt the
lockers, it's documented that many observed 3 point turns on the twisties was
necessary to pilot thelockers thru special stages.

WRT trans am series, as well as v8 DTM, audi sport always listed either
permanent awd, or when they *had* to get specific, they listed torsen or
locked or VC.  Never had to use the street car device with verbiage like
that.  That also applied in the GTO series as well ("torsen OR viscous
coupling with torque split - no brainer there)

Looking to the here and now wrt "open" (center diff rules that is), most
successes from audi came from the torque split VC (A4 TCC), and most
successes in current WRX (all marques) come from the VC/differential lock and
the full time (not the synchro version in the TT) haldex all set at a rear
bias ratio somewhere in the 60r/40f to 70r/30f many adjustable in cockpit.

I think part of the problem in the S4tt series is the rules and/or the money
(as corey points out - audi vc apps are expensive).

No question torsens have a dark side to them.  ALL tweeking aside, if you
look at the variables that affect torque allocation, what *may* work for
Stasis, isn't at all a cure all for any quattro street car, S4tt or other.



In a message dated 4/9/02 7:40:42 PM Central Daylight Time,
t44tq at writes:

Although I am not qualified to discuss this issue in technical terms,
how do you explain that Audi Sport used locked center diffs in their
rally cars when they campaigned the UrQ and SportQ in WRC?

I know that technology advances and maybe this stuff wasn't available in
the early-mid '80s.


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