Yes, I know that underdrive pulleys reduce boost. But, by how much? Couldn't the lost of boost be "made" up by increased rpms?

Pulling numbers out of the air, but say you made max boost at 5600 rpms with stock pulleys. Could you effectively achieve the same boost levels by going to 6000 rpms with UD pulleys?

 

No, you cannot. Loose the 8 HP and make 120 HP more, sounds like a fair trade off to me.

 

I had an Asp underdrive pulley and only made ~1.5-2 psi with the stock radix pulley.....it was terrible

 

I'll take the underdrive pulleys if you switch them out, just PM me if you do..

Mitch