quattro digest, Vol 1 #3237 - 1 msg "Care to Comment" -> differential tuning

[mlp]

In recently discussing the use of, the need for and the marketing being done
by one particular dynameters that has recently become accessible locally,
the shop manager made the comment that he was being told, something to the
effect, "All (hyperbole, probably some or many) the Winston Cup teams (i.e.
"money is no real object IF it will get us a competitive advantage) are
looking at, intererested in, or buying their own personal versions of the
particular form of dyno i.e. it's capable of measuring power, or more
importantly isolating power loss, at each individual wheel.  He said since
rules on engine displacement and air intake formulas have gotten so tight &
stringent, the teams all pretty well know how much bhp they can make their
engines make; and know they aren't going to be able to squeeze any more
ponies out of them.

So a big part of the racing team focus now is on how to make the chassis
components, particularly the gears in the transmission & differential, as
light and efficient as possible.

I suppose "differential tuning" would fall in this category.

Your comment touches on another theme / debate that turns about the use of
this dynometer in particular, and the "hard" data supplied by all chassis
dynometers in general when the bar stool crowd gets around to trying to
intelligently discuss or compare tuning results from car to car, engine to
engine etc.  And that is (a) do you know if the figures you are throwing out
are wheel power numbers; of flywheel numbers?  (b) can you tell if the
"chart" you're looking is "raw" data; or an "adjusted for:  "tcf"
(transmission correction factor, aka drive line loss aka ????); temperature
or altitude; or ????

In the quattro world I've seen an interesting range of numbers used for some
of these efforts to convert apples to oranges into an apple to apple
comparison.  They've ranged all the way from a suggested 10% adjustment on
an AWD 996 Porsche (see, for example
http://www.evoms.com/p_996tttune.html  to
25% for AWD Audi Quattro drivelines; to @ 21% for a triptronic FWD VW box
(see the March/April 2002 issues of EuroTuner for a 2 part series on a PES
1.8liter VW Jetta tuning/dyno/tuning saga.)

Anyone dealing with a machine shop who wants to offer to "blueprint" you
center diff?

mlp


~-----Original Message-----
~From: quattro-admin at audifans.com [mailto:quattro-admin at audifans.com]On
~Behalf Of quattro-request at audifans.com
~
~Message: 1
~Reply-To: <randrews at sbcglobal.net>
~From: "Rob Andrews" <randrews at sbcglobal.net>
~To: <quattro at audifans.com>
~Subject: Care to comment?
~Date: Sun, 7 Apr 2002 09:22:05 -0500
~
~From stassis engineering....
~Differential Tuning
~
~Tuning the center differential provides one of the most significant
~performance gains available to the Quattro owner.
~