JFAIR

What is the hp and tq difference b/t the ur underdrive and stock diameter pulleys. dynos would be helpful.

thanks for the responses

blasian

iTrader: (29)

I've heard that there is hardly any difference at all.

DavesZ#3

iTrader: (26)

Most of the power gains from any of these pulleys is from the lower weight, not the underdrive effect. The UR website has a white-paper on this explaining the details.

sentry65

iTrader: (11)

I think it's like a 1.5-2whp/tq difference

IMO it's worth having the stock diameter anyway for better alternator and A/C performance

DavesZ#3

iTrader: (26)

Plus you get to keep the stock belts!

Unorthodox_Z

I have them, they don't offer very much in the form of extra power like they do on...lets say an LS1. But it is a little bit more. They biggest advantage is the decrease in rotational mass which allows for a noticeably quicker rev speed. I like them, plus its a pretty blue....um.... I didn't say that....

JFAIR

thanks for the feed back....anyone else? can i hear from someone that has the stock diamater ur pulley.

Ztalker

one thing to consider is that the stock steel pulley is 5 lbs. heavier than the much lighter one piece UR pulley, the stock pulley is actually welded together from two pieces.

blasian

iTrader: (29)

QFT.

Z1 Performance

iTrader: (564)

UR offers a stock diameter pulley and pulley set as well as underdriven

http://www.z1auto.com/prodmore.asp?m...ine&prodid=718