Go Fast Bits Lightweight Alternator Pulley | 13-20 Subaru BRZ / 13-20 Scion FR-S 2221

GFB Pulley Kit: GFB lightweight pulley kits are made from aircraft-grade 6061-T6 aluminium and offer faster acceleration through significant weight reduction on the crankshaft. The effect is similar to a lighter flywheel, and the car feels more lively and willing to rev.Most of our kits are underdriven, which means the accessories are driven slightly slower to reduce parasitic losses. It should be noted that our underdrive pulley kits do NOT adversely affect the operation of the accessories. If they did, we would not sell them!*Features** Improved throttle response and acceleration through significant reduction of rotating mass* Engine feels more free-revving* Under-driven kits offer more power through reduction of parasitic losses from the accessories with NO adverse affects on their operation