GFB lightweight pulley kits for the Subaru BRZ/Scion FR-S are made from aircraft-grade 6061-T6 aluminum 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. Reduction in rotating inertia allows the engine to accelerate throughout the rev range much more efficiently. This allows you to get up into the power band much faster. As the pulleys are not underdriven, the stock belts can be re-used. GFB offers a complete pulley kit, but individual pulleys are available.
Crank Pulley: OEM - 4.9 lbs / GFB - .75 lbs
Water Pump Pulley: OEM - 1.0 lb / GFB - 0.75 lbs
Alternator Pulley: OEM - 0.4 lb / GFB - 0.18 lbs