Alternator pulley upgrade?

[blocke]

Ireland Engineering sells a 5'' alternator pulley, for less parasitic draw at higher RPM's. But its like $95 bucks.

Is there anything preventing anyone from just using any old v-rip 5'' pulley, like from a junkyard or cheaply available elsewhere? Anything specific to our pulleys that would prevent that?

[jlevie]

You'd have to find a smaller pulley with the right mount and offset. Offhand I don't know of any car that would have a suitable pulley.

The parasitic draw of the alternator is determined by the electrical load and the state of the battery charge. If the battery is fully charged and you aren't using the headlights and or HVAC, the alternator load will be close to zero. So I question the wisdom of an underdrive pulley.