Go Fast Bits Underdrive Pulley Kit 2008-2014 WRX / 2008-2021 STI
This GFB Pulley Kit comes with the crank, alternator and power steering pulleys. Having large heavy pulleys spinning takes away power that is better spent moving the car. This kit takes care of that by replacing the crank pulley with a lighter version that underdrives the power steering and alternator yet leaves the A/C compressor spinning at normal speeds.
Total Mass for GFB Pulley Kit : 1.38lb
Total Mass for Stock Pulleys : 6.69lb (STI) / 5.81lb (WRX)
Mass Savings : 5.31lb (STI) / 4.43lb (WRX)