SKU: 12002-KK001 | UPC: 4957266620069
HKS Pulley Upgrade Kit for 2004-2021 Subaru WRX STI
The HKS Pulley Upgrade Kit transforms supercharger performance on Subaru WRX STI models from 2004 to 2021 equipped with HKS GT2 Supercharger. This kit features a smaller drive pulley that spins the supercharger faster for higher boost levels and substantial horsepower increases. Direct bolt-on design ensures seamless integration and reliable power delivery on the track or street.
Key Features
- 20% Smaller Pulley Diameter: Increases supercharger RPM by 20 percent raising boost from 6 psi to 10 psi for immediate power gains up to 50 whp
- Billet CNC Aluminum Construction: Lightweight durable material resists wear and maintains balance at high speeds
- Complete Kit Contents: Includes pulley belt and hardware for straightforward replacement without additional parts
- Direct Fit for HKS GT2: Engineered exclusively for HKS Supercharger Kit 12000-KK001 on EJ257 engines
- Dyno Tested Results: Verified gains in torque and horsepower across 4000-7000 RPM range
Product Notes
- Requires existing HKS GT2 Supercharger installation
- Monitor boost levels after install to prevent overboost damage
- Special order item ships within 3-5 business days
Installation Notes
- Professional installation recommended.
- Remove stock supercharger pulley using HKS pulley tool set
- Compatible with OEM belt tensioner no modifications needed
This Part Fits
| Year | Make | Model | Submodel |
|---|---|---|---|
| 2004-2007 | Subaru | Impreza WRX STI | All (EJ257) |
| 2008-2014 | Subaru | Impreza WRX STI | All (EJ257) |
| 2015-2021 | Subaru | WRX STI | All (EJ257) |
Why Choose HKS?
- Motorsport proven in Super GT and rally championships
- 50 years of turbo and supercharger expertise
- JDM precision manufacturing for exact tolerances
Frequently Asked Questions
- Q: Will this kit fit my 2017 STI with HKS supercharger?
A: Yes fits all 2004-2021 WRX STI models with HKS GT2 Supercharger Kit 12000-KK001 and EJ257 engine - Q: What material is the pulley made from?
A: High-strength billet 6061 aluminum CNC machined for balance and longevity - Q: What is the warranty and install time?
A: HKS 1-year limited warranty 1-2 hours install time with basic tools and pulley puller
Shipping & Handling
- Method: UPS Ground
- Availability: In stock – ships same or next business day
- Packaging: Compact protective box 8 x 6 x 4 inches
- Weight: 1.65 lbs
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