Re: for sale: 85 Coupe GT, parts

[Don Hoefer <hoefer@cary.eng.pko.dec.com>]

>> 0%, drivetrain frictional losses are balanced by the reduction in rolling 
>> resistance because all four tires are recieving driving torque.

>Has anyone ever seen independent proof of this?  I know Audi makes the claim
>in all of their literature but I'm still just a teensy bit suspicious ... of
>course, most of the quattro cars have also been turbo'd and come with larger
>wheels/tires and shorter gears, which makes direct comparisons difficult.

I read in some car magazine a long time ago that this was determined in the
early development of the quattro.  Audi engineers were experimenting with
the same car (Ur-Q I believe) by enabling and disabling the quattro drive
train.  They were surprized when they found that the top speed of the 
four wheel drive version was faster than that of the two wheel drive version.
Investigation revealed that the rolling resistance of a driven wheel is
less than that of a rolling wheel.  Other factors are at play of course.
It all depends on the how the car is setup, tires, drivetrain, transmission,
etc. as to what factor dominates.  I would guess that Audi would not want
the quattro drivetrain to be a liability in any way and would therefore make
sure that there is a gain at best and no loss at worst.

Don Hoefer
'82 Coupe