ACT Heavy Duty Race Sprung 4 Pad Clutch 2004-2021 STI / 2007-2009 Legacy GT Spec B

The SB10-HDG4 kit combines ACT’s Heavy Duty pressure plate with a 4-pad spring-centered race disc for high-performance applications. The diaphragm-style pressure plate increases clamp load, reduces deflection, and maximizes clutch life. The 4-pad spring-centered disc damps torsional vibrations for quieter operation and resists failure under harsh conditions. Engagement is harsher, but shifting is faster. The 4-pad spring-centered disc is well-suited for smaller disc sizes and smaller engines. Monoloc provides a one-piece direct replacement or upgrade to the standard two-piece wedge collar and wire ring, ensuring uniform bearing and pressure plate loading for proper alignment and long-term reliability.

Specs

• Torque Capacity: 668 ft/lbs (88% over OE)
• Disc Material: Ceramic
• Disc Diameter: 9.4 in / 240 mm
• Input Shaft Diameter: 1 in
• Pressure Plate Type: Heavy Duty
• Product Weight: 17.2 lbs

Performance Characteristics

• Feel: Light to moderate pedal effort, aggressive engagement, OE to mild gear rattle, confidence during hard shifts
• Life: Moderate friction life, extended by ACT’s exclusive diaphragm design, dramatic improvement in release mechanism life
• Quality: Precisely assembled, accurately balanced, uses ceramic friction materials for high heat tolerance and maximum performance, major improvement in release mechanism
• Recommended Use: High horsepower street or race use
• ACT Difference: 100% clamp load tested, dynamically balanced for smooth high RPM reliability, includes ACT’s patented Monoloc