ACT Mod-Twin 225 HD Sprung Race Clutch Kit -2004-2021 Subaru STI

Description:

ACT Mod-Twin 225 Heavy Duty Rigid Race Clutch Kit for 2004-2021 Subaru WRX STI

The ACT Mod-Twin 225 Heavy Duty Rigid Race Clutch Kit for 2004-2021 Subaru WRX STI is a twin-disc clutch system designed for builds that have exceeded what a single-disc clutch can reliably hold. Two 225mm friction discs multiply the friction surface and heat capacity beyond any single-disc alternative. Target application: high street/track performance builds.

DETAILS

• System: ACT Mod-Twin 225, twin-disc
• Clamp tier: {tier_name}, {holding} torque capacity target
• Disc type: Rigid Race, aggressive, immediate race engagement
• Twin-disc design: multiplied friction surface and heat capacity
• Disc diameter: 225mm
• Includes: complete twin-disc assembly, pressure plate, flywheel, hardware
• Use case: high street/track performance builds

The Mod-Twin 225 uses two 225mm discs stacked with an intermediate plate between them. The twin-disc design fundamentally changes the clutch's torque capacity equation, doubling the friction discs more than doubles the effective friction surface while keeping the package size manageable. The Heavy Duty pressure plate clamp load is calibrated to work with the twin-disc geometry for the stated torque capacity target.

Rigid discs for maximum holding power and fastest shifts. On a twin-disc system, the spring-center construction in the sprung variants properly manages the torsional vibrations generated by the dual friction interface. Rigid disc variants are for competition applications where shift speed is the only priority.

What's in the Box

• ACT twin-disc clutch assembly (both discs)
• ACT pressure plate
• ACT flywheel
• Hardware and alignment tool
• Installation instructions

Why Choose ACT

Advanced Clutch Technology has been manufacturing performance clutch systems in the United States since 1993. Every ACT pressure plate uses a proprietary diaphragm design that increases clamp load and reduces deflection compared to OEM units, and every diaphragm goes through a four-stage heat-treating process before it leaves the factory. The result is a clutch system that holds more power than the stock unit, engages more precisely, and lasts longer under the kind of driving that wears factory clutches out quickly. ACT designs each application from scratch rather than modifying OEM tooling, which means the fitment is precise and the performance is intentional. Whether the build is a street-driven daily driver or a dedicated track car, ACT offers a kit at the correct specification for the use.

The RallySport Take

The Mod-Twin 225 Heavy Duty is for 2004-2021 Subaru WRX STI builds that have run out of single-disc options. If the Heavy Duty single-disc Xtreme kit is not holding, the twin disc is the next step, not a larger single disc. ACT's twin-disc kits are validated specifically for this platform and use the correct flywheel included with the system. Fits 2004-2021 Subaru WRX STI as listed in the fitment table.

Fitment