BigAce

Hey guys im in the process of having a motor built for my 07 denali.

I have a huge zapco amp that draws a lot of current and i want to install a smaller pulley on the alternator to give it a little more juice at idle. I am concerned however, that i may damage the alternator by having it spin too fast when my engine is turning 6500+ rpm.

the stock pulley looks to be 60mm and the one i am looking at buying is a powermaster 54mm.

Do you guys think that it would be a good idea to go with this smaller pulley?

not too sure if my math is correct, but I think that pulley would only give me a 9% overdrive, so at 6500 engine rpms the alt will be turning at what would be 7085 with a stock pulley.

I may wind it out to near 6700 or 7000 if I get the okay from my engine builder and he says my valvetrain can handle it, so the alt will be going at around what would be 7500 rpm

Is there anything wrong with spinning the alternator at these speeds?

should i keep the stock pulley to keep it from overheating or otherwise burning out?

99Bluz28

iTrader: (35)

No, don't do it. Do the "big 3", an then raise the idle speed to 800-850rpm if you still need to. You really don't want to be spinning it beyond 6k very often even with the stock pulley. If you do then I'd also install a UD alt. pulley.