hey all
i have a ba falcon xr6 and i was thinking i have a cia and know i think its time for a under drive pully but i dont know how and what it dose so if eny one could explaine it to me it would be a really help, thanks all

As far as i know, they reduce the rotational speed of the accesories that run off the drive belt. Since they're spinning slower they don't drain as much power, but then again they're not running as fast as they were designed, so if they're running too slow they won't fucntion correctly.