ACT Mod-Twin HD Street Kit with Sprung Mono-Drive Hub for 2004-2021 Subaru WRX STI (T1S-S05), 700 lb-ft

Fits select 2004-2021 Subaru Impreza WRX STI and WRX STI models.

The ACT T1S-S05 Mod-Twin HD Street Kit is engineered for high-performance AWD street applications, bridging the gap between extreme torque capacity and daily drivability. This kit utilizes a modular design that doubles the available organic friction surfaces, providing a 700 lb-ft torque capacity while maintaining a smooth engagement and consistent pedal feel. The heart of the system is the ultra-durable sprung Mono-Drive hub, which reduces driveline shock and protects the input shaft from torsional vibration.

Every diaphragm spring undergoes an exclusive four-stage heat-treating process to ensure long-term reliability and a predictable pedal effort. The steel-backed organic friction plates offer a stable friction coefficient and high heat capacity, essential for the demands of high-powered street cars. The kit includes a CNC-machined and dynamically balanced flywheel for smooth operation across the RPM range. The Mod-Twin series is fully rebuildable, allowing for long-term serviceability without replacing the entire assembly.

• Manufacturer Part Number: T1S-S05
• Torque Capacity: 700 lb-ft
• Sprung Mono-Drive hub assembly for vibration dampening
• Exclusive four-stage heat-treated diaphragm spring
• CNC-machined and dynamically balanced flywheel
• High-quality steel-backed organic friction plates
• Includes: Pressure plate cover, diaphragm spring, friction plates, Mono-Drive hub, floater, patented Monoloc collar, release bearing, alignment tool, and pilot bearing (if required)