ACT T1S-S05 Mod-Twin 225 Heavy Duty Sprung Street Clutch Kit for 2004-21 Subaru

Vehicle Fitment

• 2004-2006 Subaru Impreza WRX STI (2.5L H4 Turbo GAS FI, Manual)
• 2007-2009 Subaru Impreza WRX STI / WRX STI Limited (2.5L H4 Turbo GAS FI, Manual)
• 2010 Subaru Impreza WRX STI / WRX STI Special Edition (2.5L H4 Turbo GAS FI, Manual)
• 2011-2014 Subaru Impreza WRX STI / WRX STI Limited (2.5L H4 Turbo GAS FI, Manual)
• 2015-2021 Subaru WRX STI (Base/Limited/Sport/Series/TYPE RA, 2.5L H4 Turbo GAS FI, Manual)

Features

• Heavy duty Mod-Twin design with double organic friction surfaces for enhanced durability
• Sprung Mono-Drive hub reduces driveline shock and extends input shaft life
• Soft progressive engagement with light pedal effort for street and street/strip use
• Forged aluminum pressure cover and exclusive diaphragm for strength and heat tolerance
• CNC-machined, dynamically balanced flywheel included
• Patented Monoloc one-piece collar improves release bearing alignment
• Floater plate and sprung discs provide smooth shifting with minimal gear rattle
• Fully rebuildable design - many components available separately

Specifications

• Clutch Disc Diameter: 8.8 in / 225 mm
• Disc Material: Organic friction plates
• Disc Style: Twin Mod-Twin sprung units
• Pressure Plate Type: Heavy Duty diaphragm
• Input Shaft Diameter: ~1 in
• Spline Count: 24 splines
• Approx. Torque Capacity: ~700 ft-lbs
• Product Weight: ~28.1 lbs
• SFI Rating: 1.2 certified

Included Components

• 1x CNC-machined dynamically balanced flywheel
• 2x Organic sprung friction discs
• 1x Heavy Duty diaphragm pressure plate
• 1x Sprung Mono-Drive hub assembly
• 1x Floater plate
• 1x Patented Monoloc collar
• 1x Release bearing
• 1x Clutch alignment tool
• 1x Pilot bearing

Product Description

The ACT T1S-S05 Mod-Twin 225 Heavy Duty Sprung Street Clutch Kit is a premium performance clutch assembly engineered for select **2004-2021 Subaru WRX STI** models equipped with the 2.5 L turbocharged flat-4 engine and manual transmission. This Mod-Twin design features two organic friction discs paired with a heavy duty diaphragm pressure plate and a sprung Mono-Drive hub, which together deliver excellent torque capacity (around **700 ft-lbs**) while maintaining smooth engagement and light pedal effort suitable for street and street/strip applications. The Monoloc one-piece collar improves release bearing alignment and long-term durability compared to traditional wedge collars.

Included in the kit is a CNC-machined, dynamically balanced flywheel and all necessary installation components - making it a comprehensive upgrade over many OEM clutch setups. The twin friction surfaces provide more wear area and improved heat tolerance, resulting in longer life under high-power conditions. Precision engineering and modular rebuildability mean you can service individual components as needed, extending the overall service life of this high-performance clutch system for enthusiasts and daily drivers alike.