Underdrive Pulley
Thread Starter
Registered User
Joined: Dec 2008
Posts: 27
Likes: 0
Underdrive Pulley I have been looking into an underdrive pulley for my 02 Z28 and i was hoping to get some feedback and opinions. How much time did you pick up if any? Is it worth the money? What is a good brand? Is it an easy install? ext.
we still have the kits avail at a good price, just no longer free shipping and the belts cost now, but they are still on the site. they run like $260 with the balancer, reusable arp style bolt, and the correct belts.
the one for the fbody will be kpbu1480ss25 for the 25% ud kit.
i have seen very good dyno results using this setup, and really no adverse problems from installing it unless you have an abnormally high elec demand on the car
the one for the fbody will be kpbu1480ss25 for the 25% ud kit.
i have seen very good dyno results using this setup, and really no adverse problems from installing it unless you have an abnormally high elec demand on the car
My suggestion is to do it while doing a cam swap if you plan on doing a cam. Install is a little PITA otherwise, because you will need just the right puller, and have very little room to pull it (unless you remove the fans - you might be able to get crafty and lift the radiator far enough out of the way).
If not, go for it. It's not a seat-of-the-pants difference, but every little bit adds up. I never had any cooling issues, and the only time the voltage dipped was at idle surges (big cam/heads/m6 car)
Also, keep in mind that if you have an M6 and/or plan on putting a stroker in there, harmonics become an issue. At that point, a high end damper (ATI, etc) makes much more sense.
If not, go for it. It's not a seat-of-the-pants difference, but every little bit adds up. I never had any cooling issues, and the only time the voltage dipped was at idle surges (big cam/heads/m6 car)
Also, keep in mind that if you have an M6 and/or plan on putting a stroker in there, harmonics become an issue. At that point, a high end damper (ATI, etc) makes much more sense.
The whole time I was looking/asking around about them while I was doing my build I kept hearing that you could expect to see 8-10RWHP, which is about the same as a ported throttle body. You can definately tell a big difference visually and weight wise. I cant tell how much it made a difference cause so much was added while the motor was out of the car. I got my ASP from Vengeance. Came with a new GM crank bolt (Ron said he didn't like the ARP because of the washer it uses) and I paid to get the belts. As far as I seen they had the best price on the ASP. They also have the powerbond for cheaper. As far as pulleys go I've always heard them ranked ATI ,ASP, SLP, Powerbond.
