Pulley Kit - Under Drive - Belt Included - Aluminum - Black Anodized - Subaru WRX 2008-14 - Kit

Pulley Kit

It might be hard to imagine how reducing the mass of a pulley makes a car go faster, but accelerating a heavy factory pulley from say 3000-7000 RPM in a second or two saps a measurable amount of torque. GFB Lightweight Pulleys reduce inertia by up to 85%, so most of the torque that used to accelerate the pulley can now be applied to the wheels.

Additional Information

3-piece underdrive pulley kit (Crank, alternator & power steering pulleys & required bel

Application Summary

Subaru Suits WRX/STi MY08-14, Liberty GT MY03-12, Forester XT MY09-12)

Part Type

Engine Under Drive Pulley Kit

• Sharper Throttle Response and “urge”, engine feels more lively and willing to rev, up to 85% rotating inertia reduction, will not cause engine damage, no negative effects on driven accessory performance

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Product Downloads

#	Document Type	Download
1.	Installation Instructions

Installation guides, warranty details, and other supporting documents are provided by the supplier. In some cases, these files may originate from regions outside your locale, meaning instructions, warranty procedures, and images may not fully align with your specific vehicle or region (e.g., LHD vs. RHD differences, return policies, etc.). If you need clarification, please contact a StreetFX support agent.

Reference Information

Pulley Kits, 3 Piece, Underdrive, Crank, Alternator, Power Steering Pulley, WRX/STi 2008-20, Liberty GT 2003-12, Forester XT 2009-12, Kit

Go Fast Bits lightweight underdrive pulley kits are made from aircraft-grade 6061 T-6 aluminum, anodized black for a stealthy appearance with superior wear resistance, and lightened to offer faster acceleration through significant weight reduction. GFB pulley kits are designed to improve acceleration by reducing the rotational mass (inertia) on the crankshaft as well as parasitic loads from the driven accessories. The effect is similar to a lighter flywheel, and the engine feels livelier and more willing to rev.

Concerned about possible adverse effects of lightweight pulleys and underdriving? Rest assured GFB has done their homework. The underdrive ratios have been optimized to ensure there are no adverse effects on the performance of the accessories, and while it is true that some engine types do suffer harmonic issues from lightweight pulleys, GFB steers clear of those. Go Fast Bits kits are thoroughly application tested and do not cause engine damage in the short or long term.