Upgrade your Subaru WRX or WRX STI with the Go Fast Bits Underdrive Pulley Kit, designed to boost performance by reducing rotational mass. This premium kit replaces the heavy stock crank, alternator, and power steering pulleys with lighter versions, allowing more engine power to reach the wheels instead of spinning heavy components. Ideal for 2008-2014 WRX and 2008-2021 STI models, it’s a smart upgrade for enthusiasts seeking better throttle response and efficiency.

The kit includes a lightweight crank pulley that underdrives the alternator and power steering pulleys while maintaining normal A/C compressor speed. Total mass for the GFB kit is just 1.38lb compared to stock weights of 6.69lb (STI) and 5.81lb (WRX), saving up to 5.31lb on STI models. This reduction in rotating mass improves engine responsiveness and overall driving feel.

Perfect for Subaru performance enthusiasts looking to optimize their drivetrain, this pulley kit is a reliable, high-quality upgrade. Shop now at Subimods and enhance your WRX STI’s power delivery with confidence.