ACT T1R-S05 Mod-Twin 225 HD Sprung Race Clutch Kit for Subaru WRX STI

T1R-S05 Mod-Twin 225 HD Sprung Race Kit performs aggressive launches and smoother shifting in high powered AWD’s by combining twice the ceramic friction surfaces with an ultra-durable Mono-Drive sprung hub assembly in a completely modular design. Each diaphragm spring endures an exclusive four-stage heat treating process providing a consistent light pedal feel. Puck-style Friction Plates with high quality ceramic friction materials deliver high friction coefficient, superior heat capacity, and long clutch life. These Friction Plates uniformly transfer torque to a Mono-Drive sprung hub assembly which extends input shaft life and reduces driveline shock from torsional vibration. This kit includes a CNC-machined and dynamically balanced flywheel, pressure plate cover, diaphragm spring, face, puck-style ceramic friction plates, sprung Mono-Drive hub assembly, floater, patented Monoloc Collar, release bearing, alignment tool and pilot bearing (if needed). Mod-Twin clutches are fully rebuildable and most components can be ordered separately. Mod-Twin 225 HD Sprung Race Predictable aggressive engagement, light pedal effort, quick shifting, possible start-off judder with OE to mild transmission gear noise; Forged Aluminum Cover, Mono-drive hub, exclusive diaphragm, premium friction materials, and hardened wear points ensure this long-life twin performs and survives under the most demanding conditions; Delivers maximum performance and high heat tolerance by combining robust design, strategic features, choice materials, and close tolerances; Drag, Road, or Rally Racing; Applying tactical engineering to the Mod-Twin, ACT presents unique solutions to common tradeoffs found on twin disc clutches, resulting in an ultra-durable, customer serviceable, long-lasting clutch with very high torque capacity. All are 100% clamp load tested, balanced and SFI certified

• "Excellence in Performance", backed by the best one-year warranty in the industry!

The ACT T1R-S05 Mod-Twin 225 HD Sprung Race Kit is engineered for aggressive launches, rapid shifting, and high-power all-wheel-drive applications. Its twin-disc configuration combines twice the ceramic friction surface with an ultra-durable sprung Mono-Drive hub assembly, delivering high torque capacity and improved driveline control. Designed for drag, road, and rally racing, this clutch is intended for demanding competition use and is not recommended for street applications.

Premium puck-style ceramic friction plates provide a high coefficient of friction, excellent heat capacity, and extended clutch life. The sprung Mono-Drive hub helps reduce torsional vibration and driveline shock while supporting longer input shaft life. A forged aluminum cover, hardened wear points, CNC-machined flywheel, dynamically balanced components, and close manufacturing tolerances contribute to consistent performance. The diaphragm spring receives ACT’s exclusive four-stage heat-treating process for predictable engagement and a lighter pedal feel compared with many high-capacity race clutch designs. Some start-off judder and mild transmission gear noise may occur during operation.

The ACT T1R-S05 is fully rebuildable, allowing most major components to be serviced or replaced separately. Every unit is clamp-load tested, balanced, and SFI certified. This kit is rated for torque capacities up to 895 lb-ft and includes the components required for installation, including a release bearing and pilot bearing when applicable. Application fitment includes the 2015–2018 Subaru WRX STI. ACT supports this performance clutch with a one-year warranty.

What's Included: CNC-machined and dynamically balanced flywheel, pressure plate cover, diaphragm spring, clutch face, puck-style ceramic friction plates, sprung Mono-Drive hub assembly, floater, patented Monoloc Collar, release bearing, alignment tool, and pilot bearing when required.

Features:

• Twin-disc ceramic friction design: Provides increased friction surface area, high heat tolerance, and strong torque capacity for high-performance AWD applications.
• Sprung Mono-Drive hub assembly: Helps reduce torsional vibration and driveline shock while supporting improved input shaft durability.
• Four-stage heat-treated diaphragm spring: Delivers consistent clamp performance with predictable engagement and lighter pedal effort.
• Fully rebuildable race construction: Uses serviceable components, balanced assemblies, hardened wear points, and SFI-certified performance for drag, road, and rally racing.

Fitments:
2004 Subaru Impreza WRX STI
2005 Subaru Impreza WRX STI
2006 Subaru Impreza WRX STI
2007 Subaru Impreza WRX STI
2007 Subaru Impreza WRX STI Limited
2008 Subaru Impreza WRX STI
2009 Subaru Impreza WRX STI
2010 Subaru Impreza WRX STI
2010 Subaru Impreza WRX STI Special Edition
2011 Subaru Impreza WRX STI
2011 Subaru Impreza WRX STI Limited
2012 Subaru Impreza WRX STI
2012 Subaru Impreza WRX STI Limited
2013 Subaru Impreza WRX STI
2013 Subaru Impreza WRX STI Limited
2014 Subaru Impreza WRX STI
2014 Subaru Impreza WRX STI Limited
2015 Subaru WRX STI Base
2015 Subaru WRX STI Launch Edition
2015 Subaru WRX STI Limited
2016 Subaru WRX STI Base
2016 Subaru WRX STI Limited
2016 Subaru WRX STI Series.HyperBlue
2017 Subaru WRX STI Base
2017 Subaru WRX STI Limited
2018 Subaru WRX STI Base
2018 Subaru WRX STI Limited
2018 Subaru WRX STI Type RA
2019 Subaru WRX STI Base
2019 Subaru WRX STI Limited
2019 Subaru WRX STI S209
2020 Subaru WRX STI Base
2020 Subaru WRX STI Limited
2021 Subaru WRX STI Base
2021 Subaru WRX STI Limited

Air Freight Prohibited: false
Not Carb Approved: false
Ltl Freight Required: false
Prop 65: Y
Part Type: automotive
Epa: N/A
Carb Acknowledgement Required: false
Regular Stock: t
Units Per Sku: 1