Originally Posted by LophatXB

Wow, I really opened a can with one question. I guess, part of my deal would be a small increase in performance as a bonus. I do plan an a couple other performance mods, like the CAI and a custom cat back exhaust. I guess, it would be good to know that I am one of those heavy footed drivers at times in daily traffic, but I have cut back since I went down in power from my Z4 to the XB. I was actually looking at doing the whole set of pulleys that NST offers, but I wasn't sure whether is was better to stick with stock diameter on the main drive pulley or to use the underdrive. From what I have read too, is that anything over 15% under driven will be bad for the electrical system and such. But the NST, if I remember right, is only about 10% under drive. And if changing the all three pulleys would make the car more drivable around the city, then that too is relieving some of the everyday stress of driving I imagine. And excuse my ignorance, but what is NVH? I read these post several times and couldn't figure it out and I am pretty mechanically inclined and pretty good at deciphering abbreviations. Thanks for all your feed back.

Originally Posted by CIONIDE

Why not just get the standard lightweight crank pulley, and skip the UDP? Won't that allow the engine to spin more freely due to the decreased rotational mass of the pulley without reducing alternator output or requiring a different belt?

I'm a bit ignorant to all this, and have thought about this mod myself, so any feedback to these comments is certainly appreciated.

Originally Posted by LophatXB

Wow, I really opened a can with one question. I guess, part of my deal would be a small increase in performance as a bonus. I do plan an a couple other performance mods, like the CAI and a custom cat back exhaust. I guess, it would be good to know that I am one of those heavy footed drivers at times in daily traffic, but I have cut back since I went down in power from my Z4 to the XB. I was actually looking at doing the whole set of pulleys that NST offers, but I wasn't sure whether is was better to stick with stock diameter on the main drive pulley or to use the underdrive. From what I have read too, is that anything over 15% under driven will be bad for the electrical system and such. But the NST, if I remember right, is only about 10% under drive. And if changing the all three pulleys would make the car more drivable around the city, then that too is relieving some of the everyday stress of driving I imagine. And excuse my ignorance, but what is NVH? I read these post several times and couldn't figure it out and I am pretty mechanically inclined and pretty good at deciphering abbreviations. Thanks for all your feed back.