Underdrive Pulley
09-20-2011, 08:16 PM
#1
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Underdrive Pulley What is the real reason for people doing this? Does it help the power curve? What is the biggest advantages for people doing this modification. Ive noticed it a lot in people sigs.
09-21-2011, 03:05 PM
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The basic idea for it is to "free up" more hp. It's a very minimal gain to my knowledge. All of your belt driven accessories rob power from the engine such as power steering, a/c, oil pump, ect. The aftermarket underdrive pulley is smaller than the stock i believe and is supposed to turn those accessories easier. Anyone can jump in and correct me if im wrong. Hope this helps.
09-21-2011, 10:44 PM
#3
The basic idea for it is to "free up" more hp. It's a very minimal gain to my knowledge. All of your belt driven accessories rob power from the engine such as power steering, a/c, oil pump, ect. The aftermarket underdrive pulley is smaller than the stock i believe and is supposed to turn those accessories slower. Anyone can jump in and correct me if im wrong. Hope this helps.
09-27-2011, 03:57 PM
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IMO it seems shops push them when they do cam work on a car. I've seen claims of 8-10whp from an UDP, but its rare you seem someone do "just" and UDP with no other mods to be measured (and dynoed before and after with just the mentioned).
The only graph I've found that was simply a UDP before and after, netted an 1-2whp gain across the board. It basically looked like two lines drawn on top of each other with the UDP having an average slight gain.
I'd love for the sponsors that claim 8-10 throw a graph up just a UDP before and after, but I doubt I'll see one.
The only graph I've found that was simply a UDP before and after, netted an 1-2whp gain across the board. It basically looked like two lines drawn on top of each other with the UDP having an average slight gain.
I'd love for the sponsors that claim 8-10 throw a graph up just a UDP before and after, but I doubt I'll see one.
09-27-2011, 05:11 PM
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I don't think it's really worth it. Had them on my Z28 and if I did gain anything it wasn't anything to care about. Besides watching the Alternator half *** charge.
09-28-2011, 04:46 PM
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