Was wondering if anyone has changed their idler pulley? And if there are any performance idler pulleys or if the only performance ones are the underdrive pulley? Does anyone have a kit that comes with a idler pulley that acctually has benifits in performance. thanks

 

also wondering whats the difference between the underdrive alt pulley and the overdrive. Has anyone installed the ASP ones from texas speed that are like 25 bucks. How good are they. Or should I just get the crank pulley kit...?

 

An idler pulley does just what it's name implies. Idles, it does nothing so there is no performance involved.
Underdrive makes things go slower=uses less power
Overdrive makes things go faster=uses more power