ALTERNATOR PULLEYS, WHAT YOU SHOULD KNOW

Increase Alternator Output and Cooling with Pulley Size

6 Groove Pulleys shown above , L-R: 2-3/8" diameter, 2-1/4", 2", and 1-7/8"
Yes, you can increase your alternators overall output as well as increase power output at engine idle speeds.
Check the size of the pulley on your alternator. If you are having problems with overall alternator output or charging at engine idle, maybe a smaller pulley is all you need. The most common pulleys on GM, Ford and Daimlier/Chrysler vehicles are the 6-groove 2-7/16, 2-3/8 and 2-1/4 inch pulleys, by reducing the pulley size to 2" or 1-7/8" your alternator will start producing power sooner and produce more power cruising down the boulevard or on the highway. Also, because your alternator is spinning faster the fan will move more cooling air through the alternator adding to component life, to little air flow can burn up an alternator.

Alternator pulley belt wrap, what does that mean? Belt wrap is the contact area the belt has with the pulley. If the belt were to wrap completely around the pulley that would be 100% belt wrap. having 100% belt wrap completely around the alternator would be impossible but the greater the belt wrap the longer belt and pulley life can be expected. Alternators take quite a bit of power to run so good belt contact with the pulley is very important. If you have poor belt wrap or your pulley becomes "glazed" a glazed pulley looks very smooth it may be time to replace the pulley.