Stock Alternator pulley was 2.2" diameter.
Installed a 2.6" diameter pulley, resulting in 18% lower rotor speed, less parasitic loss, and takes up a bit more belt slack ( tension).
Stock 8292 Alternator, as configured with 2.6" pulley makes 120 amps at idle.

 

But does it produce that power efficiently now... o.O

 

this is info I dug up the other day trying to find out if aluminum pulleys vs steel

>>As for the underdrive sheave system a car with even a 140am alternator putting out 13.8-14.1 volts, which equates to a maximum output of 1974 watts, or 2.6471 horsepower to run the alternator. So, accounting for the inefficiencies, your alternator is only pulling 3HP at peak output (all accessories running). More often, it's more like 1.5HP at a 70A output, where a 1/3 underdrive sheave would save you only about 0.5HP. At best, you'll save 1.0 HP. If you only have a 70A alternator, you can cut those "gain" figures in half.<<

 

I immediately thought about that post when i read that yesterday...

 

lol i did to ...