Underdrive Pulleys

[chvyhs]

Is anyone running underdrive pulleys? Are they worth the $100? I have a 1990 Suburban that I'm trying to squeeze every last horse out of. What have they done for you? I want to get headers or the pulleys next.

 

[DesertDueler]

I never noticed a difference when we put them on the mustangs(there are like 20 different places that make the underdrive setup for those guys) Most of the time the cars come back because they are running hot, and there battery doesnt stay charged. They slow down you fan and alt. Go electric fan to make up the power. Use a ford t-bird fan from like a 90 super coupe. I use one on my Firebird and it doesnt overheat here in Phx, AZ and it freed up 20 real wheel hp /forums/images/icons/smile.gif

 

[DesertDueler]

The reason I say this fan is because it is a single fan thats two speeds and has a built in fan shroud. You need to hook it up with relays and use circut breakers instad of fuses because the low speed pulls over 30 amps when it kicks on, and the high speed pulls more. It drops from that once it gets going though