GFB 13 Subaru BRZ / 13 Scion FR-S 3 Pc L/W Pulley Kit (Inc Crank/Alternator/Water Pump Pulleys)

This Go Fast Bits pulley kit includes the crank, alternator, and water pump pulleys. By swapping out your factory pulleys for these lighter ones, you're reducing the rotating mass in your engine. Think of it like this: the engine's job is to spin the pulleys, and the pulleys' job is to spin the accessories. When you make those pulleys lighter, the engine doesn't have to work as hard just to get them up to speed. This means more of the engine's power can go to the wheels, giving you a more responsive feel.

These pulleys are machined from a single billet of 6061-T6 aluminum, which is a strong yet lightweight material. This construction helps reduce the inertia by up to 85% compared to stock. The goal here is to make the engine feel more lively and willing to rev, with a sharper throttle response. GFB has tested these kits to ensure they bolt on without needing other modifications or tuning, and they won't negatively affect how your accessories perform.