Aftermarket Underdrive Pully, will it Destroy Your Engine

[tyrist3050]

HEHE throws in a monkey wrench* What if the UDP is balanced and has a replacement pulley for the alt?

[SuperK]

HEHE throws in a monkey wrench* What if the UDP is balanced and has a replacement pulley for the alt?

you get punched in the face for this being your first post.

[SuperK]

you can't really balance a UDP. They should be zero balanced anyways.

the biggest issue is UDPs are constructed without using a rubber damper, not that they are unbalanced.

[MrMazda92]

It's nice to see some opinions put out there on a controversial topic, I don't think I've seen this discussion on this board before.

There are TONS of posts on PT both for and against UDPs, yet I've seen zero proof that the benefits or risks even exist... It sounds simple enough to reduce the size of the pulley and "free up" horsepower, but it's never that simple with cars. You aren't shifting to a lower gear on a bicycle... These things run a fair bit more torque(understatement). That being said, at the VERY LEAST, don't throw a $15 ebay UDP on your engine... If it's been engineered, as opposed to CNC'd and mass produced in China... you're at least decreasing your chances of a problem. That goes for anything you buy, in person, or online.

I'll probably never go this route, when I see so many more viable ways to gain or free up power... If I ever do, it'll be after finding concrete evidence(with supporting data of course) that shows it's not only safe, but worth the cost.)

Woah, it's been a long time since I wrote this!

As a brief update to an ancient post, I did in fact purchase an Unorthodox UDP.
The pulley sits in my parts pile - Having been replaced with a 36-1 trigger wheel, I am hanging onto it as a "maybe someday" type item. I have found no further proof supporting or contradicting the benefits of the pulleys. If I had a 36-1 wheel for it, I would consider using it with my current build.