Action Clutch Stage 4 Clutch Kit

2004–2021 Subaru WRX STI 2.5L DOHC EJ257 Turbo AWD

Part #: ACR-1805

Overview

The Action Clutch Stage 4 Metallic Rigid Clutch Kit is designed for Subaru WRX STI enthusiasts seeking enhanced performance and durability. Built to handle aggressive driving conditions, this clutch kit offers a significant increase in holding capacity while maintaining a responsive pedal feel. Whether you're a spirited street driver, a track enthusiast, or someone pushing their vehicle to the limit, this clutch provides the reliability and performance you need.

Featuring a heavy-duty ceramic clutch system with a lightweight, unsprung hub, this kit ensures rapid heat dissipation and outstanding heat management during high-stress driving. The aggressive engagement and increased clamp load translate into improved power transfer from the engine to the wheels, supporting increased horsepower and torque gains. The slightly increased pedal pressure provides a firm, confident pedal feel without sacrificing daily drivability.

Key Features

The Action Clutch Stage 4 Clutch Kit incorporates several advanced features designed to optimize performance and longevity:

• Single diaphragm *RIGID* ceramic pressure plate for maximum holding capacity and durability under high loads.
• Reinforced drive straps enhance structural integrity, ensuring consistent engagement and long-term reliability.
• Lightweight, unsprung hub reduces rotational mass, contributing to quicker throttle response and smoother operation.
• 170% increase in holding capacity compared to stock clutch systems, making it suitable for high-power builds and aggressive driving styles.
• High-quality materials and construction ensure excellent heat dissipation, reducing the risk of clutch fade during extended spirited driving or track use.
• Designed specifically for the Subaru WRX STI 2.5L EJ257 turbocharged engines from 2004 to 2021, ensuring a perfect fit and seamless installation.

Construction & Design

The Action Clutch Stage 4 Clutch Kit features a robust ceramic friction surface mounted on a heavy-duty pressure plate. The ceramic material provides excellent heat resistance and high friction levels, supporting aggressive engagement and increased torque capacity. The reinforced drive straps and single diaphragm design contribute to a consistent pedal feel and reliable operation under demanding conditions.

The kit's components are engineered with precision, ensuring a direct, bolt-on installation that maintains factory mounting points and alignment. The use of high-quality materials and meticulous craftsmanship results in a durable, long-lasting clutch system capable of supporting high horsepower and torque levels while providing a responsive driving experience.

Installation & Fitment

The Action Clutch Stage 4 Clutch Kit is a bolt-on upgrade that requires no cutting or drilling. Basic mechanical skills and standard tools are sufficient for installation. It is recommended to have the clutch properly aligned and the flywheel inspected or resurfaced if necessary to ensure optimal performance and longevity. Due to the increased holding capacity, some drivability adjustments may be beneficial, but no special tuning is typically required.

• Direct replacement for the factory clutch system on Subaru WRX STI models from 2004 to 2021.
• Designed for use with stock or mildly modified engines; suitable for high-performance builds.
• Ideal for drivers seeking increased durability, heat resistance, and aggressive engagement for spirited driving or racing.

What's Included

• Heavy-duty ceramic pressure plate
• High-performance clutch disc with ceramic friction material
• Reinforced drive straps for durability
• All necessary hardware and bolts for installation
• Instruction manual for proper setup and break-in procedures

Ideal For

• Subaru WRX STI owners looking to upgrade their clutch for increased performance
• High-horsepower builds requiring a clutch with greater holding capacity
• Track day enthusiasts and spirited street drivers
• Drivers seeking a reliable, durable clutch system capable of handling aggressive driving styles