>Just some context - with 90 amps at 13.6 volts, assuming 85%
>efficiency the alternator will be sucking down about two horsepower
>from the belt and dissipating about 225 watts as heat.

Hmmm...Leece-Neville show this 90-A alternator using almost four
horsepower at full output:
http://www.prestolite.com/productinfo/alternators/8AR2112T/8AR2112T_curve.jpg

I guess 85% is a bit optimistic.

I've also been seeing alternators rated full output at 6,000 rpm,
with max rpm of 6,500.  Our alternator spins a lot faster than that -
just measured the sheaves, and alternator runs twice engine rpm or a bit more.

And you're right, the big three-groove crank pulley is tapered, at
least on the engine I just looked at (random 2.1l core).  I've been
looking at that thing for twenty years now...in the engine bay,
mostly.  Not that that's an excuse. <shakes head>

Yrs,
d