Free up hidden horsepower from your WRX with a Cobb lightweight crank pulley. This Cobb pulley was Built to the factory diameter of the stock main pulley, and will not underdrive your accessories or cause electrical issues. Cobb's Drive belt surface is precision machined to exact specifications of the OEM belt to ensure long belt life. Replacing your factory crank pulley, with a Cobb lightweight unit improves acceleration by reducing the rotational mass of the stock unit by as much as 4lbs. This Cobb Lightweight Crank Pulley is CNC machined from Billet 6061-T6 and anodized for a long lasting finish. Installation is straightforward can be done without jacking the vehicle or removing anything other than the belt cover, belts and stock crank pulley. This makes the Cobb light weight pulley a quick and easy install by even the most novice owner.

NOTE: 2008-2009 WRX & STi do not have a A/C belt tensioner like earlier models. Because of this, a special tool from Subaru is required to install this part.