ACT Mod-Twin 225 XT Sprung Race Cutch Kit – 04-21 STI


ACT Mod-Twin 225 XT Sprung Race Cutch Kit – 04-21 STI


The ACT Mod-Twin 225 XT 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. It has a Torque Capacity of 1120 ft/lbs.


In stock



ACT Clutch Kits stand unequaled in terms of consistent pedal feel, high torque capacity, long wear life and durability. In-house manufacturing is critical in tuning components specifically to each individual application, while maintaining the predictable ACT pedal feel across the entire catalog.

In this ACT Clutch Kit, 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.

Mod-Twin clutches are fully rebuildable and most components can be ordered separately.

Quick Specs

  • Disc Material – Ceramic
  • Torque Capacity – 1120ft/lbs
  • Torque Capacity over OE 214%
  • 8.8″ Disk
  • Feel – Predictable aggressive engagement, light pedal effort, smooth shifting, possible start-off judder with OE to mild transmission gear noise
  • Recommend use – Drag, Road, or Rally Racing

Included in Kit

  • Pressure Plate Cover
  • Diphragm Spring
  • Face
  • Puck-Style Ceramic Griction Plates
  • Sprung Mono-Drive hub Assembly
  • Floater
  • Patented Monoloc Collar
  • CNC-machined and dynamically balanced XACTR Streetlite Chromoly Flywheel
  • Release Bearing
  • Alignment Tool
  • Pilot Bearing (If Needed)

Recommended Break In Process

For organic street discs, ACT recommend breaking in the clutch for 300-500 miles with mild engagement, such as stop-and-go city driving prior to racing or spirited driving. ACT race discs usually only require a few hard slips to lap in the surfaces prior to normal driving or racing. Do not overheat the clutch during the break in period, as this can result in friction surfaces fusing together, hot spots, and friction surface glazing.


Additional Information

Weight30 lbs
Dimensions14.3 × 13.9 × 5.2 in


  • 2004-2021 STI


Installation Guide

Install Guide