Your factory crank pulley is responsible for transferring energy from your crankshaft to your water pump, a/c compressor and alternator. It does this by way of a rubber belt and it does it's job well. The drawback to the factory pulley is that it's quite heavy. Reasons for this include less expensive manufacturing and using the pulley's mass to smooth out 'noise' in the accessory system (NOT to be confused with functioning as a harmonic dampener, which it does not). The GrimmSpeed Lightweight Crank Pulley reduces the rotational mass of the system, allowing your engine to accelerate and decelerate the rotating assembly more quickly.
Part #: 095023
- 75% Reduction in Rotating Mass - weighs 1.1lb vs the 4.4lb OEM pulley
- Machined 6061 T6 Aluminum - high quality, precision construction
- Hard Anodized Finish - ensures a durable finish and resists corrosion
- Removal Tool Mounting - allows the use of the GrimmSpeed Crank Pulley Tool
- Factory Fitment - direct replacement for easy installation
The design process for this pulley ensured that a perfect factory replacement fitment was maintained while performance was maximized. It's a common misconception that the mass of a crank pulley alone determines its effectiveness. The truth is that it's actually the moment of inertia that affects the pulley's ability to improve engine and throttle response. The moment of inertia, in non-engineering terms, is a function of not only the mass of an object, but how that mass is distributed about it's rotational axis. A lower moment of inertia means that less torque is required to spin the crank pulley and, in turn, the crankshaft/engine. Our engineers took great care to keep the already minimal mass as close to the center of the pulley as possible without sacrificing its strength.
The result is a pulley that fits well, looks beautiful and works exactly as intended. From the first test drive, you'll notice smoother operation, faster response and a more enjoyable drive. Much of this is difficult to quantify, but you can see from the datalogs below that when compared to the OEM pulley, the GrimmSpeed Crank Pulley quantitatively improved throttle response.
2013+ Subaru BRZ
2015+ Subaru WRX
2012+ Subaru Impreza (FB/FA Engines Only)
2011+ Subaru Forester (FB/FA Engines Only)
2012+ Subaru Legacy (FB/FA Engines Only)
2012+ Subaru XV Crosstrek (FB/FA Engines Only)
2013+ Scion FR-S
Any returns for an exchange or refund will be allowed within 30 days from the receipt of your order and must be authorized prior to shipping with an RMA Number (Return Merchandise Authorization). To receive your return instructions and RMA# please use our online form under Returns and Exchanges! Once you receive your return instructions please ship out the item at your earliest convenience and provide the tracking number to your customer service rep. The customer will be responsible for all shipping fees. Before shipping your product back please make sure you package it up exactly how you received it and in all of its original packaging. All items must be in brand new and resalable condition. Once the item is received it will be inspected and a credit will be issued accordingly. All returns are subject to a 15% restocking fee. Any returns received without an RMA# will be charged a restocking fee and any shipping fees associated with the return. An item that does not ship directly from IIR's warehouse is considered a "special order" item and no returns will be authorized.