Random, i was wondering if having an underdrive crank pulley would affect the performance of my Turbo kit.
Since it weighs like 2 pounds wouldnt it affect the turbo to not spool up as quickly?

 

No, the underdrive pulley would free up engine HP that is wasted driving your accessories, so your engine would rev a TAD bit faster, and your turbo would spool up a TAD bit faster...but 5 HP worth of faster is hardly noticable.

Underdrive pullies have their disadvantages, make sure you are aware of them before you buy one.

 

Red made a good point a while back on these pullies, tha on a blue printed motor, they will throw them out of alignment, on small turbo/nos/na it will free up hp at expense of alternator power ie no big stereo