90 Alternator similar to 100?

[Jason Fantus]

Hey, found out what was going on with my "new" '91 100. Alternator was just
about on it's last legs when I bought it, took it over to Advance Auto Parts
(hey, I don't have my own load tester, heh :P) and put a load on it, started
giving out around 10 volts. Enough to keep it running - but just barely. The
problem with the gas gauge seems to have corrected itself, I think it had
something to do with not pushing the ignition in all the way (had the same
problem on a Volvo 740 I once had, there was a "dead spot" where if you
didn't put the key EXACTLY in the on position after starting none of the
electricals would work and the car would whirr really loudly. Guess this car
might not have one that serious...considering the fuel gauge is right above
the ignition switch.) or something. Whatever it is I hope it stays fixed
(drove a car once with a faulty gas gauge for 2 years, not fun having to
guess your fuel milage and compare it to the trip mileage and how many
gallons you remember buying!)

Anyways, since I just bought the car I'm a bit tight on available cash flow,
so I'm gonna put on a salvage (1 year warranty, of course, like that
matters) alternator until I can afford the $280 for a remanufactured 110 amp
one. I'll keep the salvage one as an emergency spare, just in case.
Online I found an alternator from a '91 90 for only about $60, which I have
enough cash for. The 90 shares the same engine with the 100, right? (2.3L
inline 5) and one would hope the same alternator (yes, its 110 amp). Could I
order this one and have it fit? Any help appreciated grately!

PS. If you think Audi parts are expensive, just look up parts for
top-of-the-line American cars, they aren't much cheaper. Had to replace the
alternator on my previous 89 olds 98 touring sedan (their "competition" for
BMWs, Benzes and Audis, but hehe I can say in compairson having owned one it
wasn't much competition :P) and it cost $175 remanufactured from a local
shop, would have been $240 from AC/Delco. And other repairs seemed to cost
way more than what I can tell from the archives on this car!

Thanks,

Jason Fantus