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


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


This kit features  ACT’s Mod-Twin 225 HD Sprung Street Kit is designed for high powered AWD street cars. It has a Torque Capacity of 875 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.

This ACT Clutch Kit unites uncompromised pedal feel, durability, engagement quality with very high torque capacity by combining twice the organic friction surfaces with an ultra-durable spring center Mono-Drive hub in a completely modular design. Each diaphragm spring endures an exclusive four-stage heat treating process providing a consistent light pedal feel. Steel-backed Friction Plates with high quality organic friction materials deliver stable friction coefficient, good heat capacity and long clutch life. These Friction Plates uniformly transfer torque to the 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 – Organic
  • Torque Capacity – 875ft/lbs
  • Torque Capacity over OE 146%
  • 8.8″ Disk
  • Feel – Soft progressive engagement, light pedal effort, smooth shifting with OE to mild transmission gear noise
  • Recommend use – Street and Street/Strip

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