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Re: 1990 Audi Coupe questions (fwd)

Bob D'Amato sez:
>   I am wondering if
> anyone has undertaken the task of changing the final gear ratio(s) such that
> the vehicle's engine speed is 20 to 30 percent less in 5th gear.  It just
> seems that the car doesn't have to rev up to 4000 rpm to go 80.

First, this probably is not really what you would want to do -- the beginning
of the powerband in these cars is 4000-4200 RPM, which is ~80 MPH in 5th.  I
think of this as the basic cruising speed, as it is the base of the powerband
in the top gear (so you have instant power for passing).  Most German cars
are actually set up this way -- correspondingly, they can typically redline 5th,
wheras the Americans, who setup 5th as a true lug-the-engine, get great EPA
milage, typically go faster in 4th than in 5th.

As far as changing ratios by way of final drive, precious few ring/pinion
sets are available from Audi.  You can swap from some other models (the 80/90's),
but it depends on the trans codes, etc.  Trans gear sets are also very limited.
I am not sure about outright trans/diff swaps -- though I am in the process of
swapping the rear diff unit for one with a Torsen.

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