Underdive pulleys and ported throttle bodys
Thread Starter
Racer
Joined: Jul 2007
Posts: 444
Likes: 4
From: Waynesboro VA
Underdive pulleys and ported throttle bodys
What are the pro's and cons? What effect does a UD pulley have on other belt driven units (AC, Alternator)? Does a ported TB cause any idling issues or tuning issues?
Instructor
Joined: Aug 2009
Posts: 242
Likes: 0
From: Orlando Florida
I have UD pulley and the only thing it effects is the battery voltage at night if you have HID. But it only happens when your sitting still at a red light. It goes back up when your moving. Its a great mod you can really feel the difference!
Le Mans Master
Joined: Nov 2009
Posts: 6,882
Likes: 234
From: Bangkok, Thailand
I just had a Powerbond 25% pulley installed on my 99 to replace the defective (wobbling) stock unit. It does feel like it revs easier and the engine also feels smoother. No drawbacks including driving it in the dark tonight - all pros, no cons.
Safety Car
Joined: Apr 2004
Posts: 3,532
Likes: 79
From: pueblo co
the deal with under drive pullys is slows down your acc. and most are not harmonic balanced...so any viberations that you get from your crank can transfer to other parts of your engine ...but again..this is a 50/50 debat..and you cant really find a good answer..i had a same size light weight pully on my stealth r/t twin turbo..and really did not notice any difference from the stock one...i highly doubt you would gain 5 to 6 hp...from an pully.maybe 1 at the most..
