Charging problems with Underdrive pulleys ? Try this.
If you have underdrive pulleys, and are experiencing charging problems when idling, this might help a little. On my EL XR8 (so I guess all other E series V8’s must be similar?) the alternator pulley is about 60mm diameter (measured at the top of the ribs). The AU 6 cylinders (and maybe V8’s too, I’m not sure) have an alternator diameter of about 52mm (again measured at the top of the ribs, not on the outside flanges). These pulleys are interchangeable, in every other aspect (i.e bore diameter, spigot length, belt type etc), so if you swap these over, you’ll speed up your alternator by about 15%. Not quite as much probably as the amount you originally slowed it down (in my case about 25%), but this seems to help.
A few tips if you decide to do this. Firstly, don’t by new from Ford ($150+), try a wreckers or auto electrician instead ($10-$20). Secondly, you’ll need a rattle gun to remove the nut securing the pulley on the alternator. In my case I still had enough adjustment left on the automatic belt tensioner to take up the slack or the reduced diameter, but this is something you’ll also need to check.
I didn't notice any loss in power with this, as you still have your waterpump and power steering running slower.
Last edited by EL1XR8; 02-25-04 at 12:56 PM.
Reason: more info added