Competition Clutch Lightweight Steel Flywheel for 2004-2019 Subaru WRX STI (2-721-ST)

Unlock quicker throttle response and snappier acceleration in your EJ257 build without sacrificing daily driveability. The Competition Clutch Lightweight Steel Flywheel (ST suffix) is the ultimate upgrade for enthusiast drivers who want a more responsive engine while preserving critical low-end torque.

Engineered from premium 4140 forged steel, this one-piece design eliminates the risk of ring-gear separation common in multi-piece alternatives. It provides the perfect balance of weight reduction and thermal capacity, making it an excellent choice for high-power street driving, time attack, and track performance.

Why Choose the Competition Clutch ST Flywheel?

• Optimized Throttle Response: Lighter mass allows your boxer engine to rev freer and drop RPMs faster for ultra-crisp gear shifts through the rugged STI 6-speed box.
• Preserved Driveability: Specifically engineered for high-performance AWD street-driven applications to retain smooth launch characteristics without excessive engine bogging or harshness.
• Perfect Clutch Compatibility: Perfectly matched and well-suited for Gravity, Stage 1, and Stage 2 clutch kits.
• One-Piece Forged Strength: CNC-machined from ultra-durable 4140 chromoly steel for maximum safety, reliability, and longevity under high-RPM abuse.

Product Specifications

• Brand: Competition Clutch
• Part Number: 2-721-ST
• Material: One-Piece 4140 Forged Steel
• Flywheel Type: Lightweight Steel (ST Series)
• Weight: 15.00 lbs

Vehicle Fitment & Application

• Year Range: 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019
• Make/Model: Subaru WRX STI
• Engine Requirements: 2.5L Turbocharged EJ257 matched to STI 6-Speed Manual Transmission

Note: Not all vehicle applications feature both ST (Street) and STU (Ultra-Lightweight) versions; this ST variant is optimized to deliver the ideal balance of performance and street manners.