Perrin 07-21 Subaru WRX STI EJ Engines Alternator Pulley - Blue
The Perrin Alternator Pulley is a small yet impactful upgrade for drivers looking to reduce parasitic drag and improve engine responsiveness. While your alternator plays a critical role in powering electrical systems, it also draws energy from the engine under load. By replacing the OEM pulley with Perrin’s lighter, CNC-machined aluminum version, you help the alternator spin more efficiently, reducing rotating mass and improving throttle response.
This upgrade is particularly popular among enthusiasts running other Perrin lightweight pulleys—like the crank pulley—as part of a full rotating assembly reduction. Though the weight savings from the alternator pulley alone are modest, the cumulative impact when paired with other lightweight components is noticeable. Expect a quicker-revving engine and improved off-idle response, especially in stop-and-go scenarios or quick gear changes.
Fitment is OEM-style, meaning the pulley slips on without any modification, and works flawlessly with factory belts and charging systems. You get a motorsport-inspired performance feel without compromising reliability or function.
- Reduces rotational mass for faster throttle response
- Precision CNC machined from lightweight aluminum
- Direct OEM-style fit—no modification required
- Complements lightweight crank pulleys for optimal performance
Perfect for enthusiasts chasing every last ounce of efficiency and response, the Perrin Alternator Pulley is a great finishing touch in your engine bay performance package.