recently i installed an underdrive pulley and a new alternator pulley. my question is should the new alternator pulley be smaller or bigger than the stock pulley. the one the came with the package that i bought is bigger than the stock one but i have heard of some people getting a smaller one when they have bought theirs. the brand that i bought is asp if it matters any.

 

It should be smaller to keep the alternator speed up with the smaller crank pulley, which slows the accessories down.

 

John

 

mine was bigger than the stock one, which would probably explain my low voltage

 

asp sells an underdrive and an overdrive pulley or the alternator. you can buy the set either way.

 

whats the difference in the underive and the overdrive pulley for the alternator????

in the set that i got it says: "ASP 25% Underdrive Crank Harmonic Balancer Pulley & 23% Underdrive Alternator Pulley, 1999-2004 GM Truck"

 

you want an overdrive alt pully not an underdrive

 

the overdrive alt pulley is smaller than the underdrive alt pulley??

 

YES! the smaller the pulley the faster the alt will spin= more voltage.

 

OK OK !!! LOL