Just wandering around the Internet today, I stumbled across the Nevo website and noticed that they have "underdrive pulleys". The 4AGE ones are 15% underdrive on the crank and 10% underdrive on waterpump and alternator, while Bill Sherwood's ones special ones are standard crank, and very large others.

 

I can understand putting smaller pulleys on the pump & alternator if you expect to be doing high revs a fair bit, but what's the advantage of underdriving the crank pulley?

They are to get the super charge to rev higher, ie more boost. I can't justify the price they put on those over drive pulleys though :dry:

 

Although I'm not quite shure what other use that would be for the 4age's (i just reliased you asked about the 4age )

Edited December 10, 200421 yr by Jason

Nevo pulleys seems to be quite highly regarded. I wonder how much they cost? If Bill Sherwood uses them, they have to be "the shitz, yo" :insane: