Why Choose ACT HDSS?

Common clutch issues:

• Slipping under power
• Weak engagement on tuned builds
• Heat fade during aggressive driving
• Premature wear

ACT Fixes That:

• Heavy-duty pressure plate increases clamp load
• Street sprung organic disc smooths engagement
• Handles higher torque without chatter overload
• Designed for street + performance balance

Translation: it holds power without making traffic miserable.

This ACT seize kit features a Heavy Duty pressure plate, Performance Street disc, release bearing, pilot bearing and alignment tool. The Heavy Duty pressure plate allows for 20 to 50 percent increase in clamp load over the stock unit.

Vehicle Fitment (Mazda Rotary Platform)

Designed specifically for:

Mazda:

• RX-8 (2004–2011)

Engine:

• 1.3L RENESIS Rotary (13B-MSP)

Transmission:

• Manual transmission only

Ideal For:

• Daily drivers with mods
• Street performance builds
• Bolt-on upgrades
• Spirited driving

If your RX-8 clutch gives up when you push it—this fixes it.

ACT’s Heavy Duty pressure plate features precision CNC machined parts, drive straps and rivets to soundly locate contact face to the duvet for quiet, trouble-free operation.

What’s Included

• ACT heavy-duty pressure plate
• Performance street sprung clutch disc
• Release bearing
• Pilot bearing (if applicable)

Complete performance-ready kit.

The Heavy Duty pressure plate could have a stock to moderate pedal feel. ACT pressure plates feature creative diaphragm designs to extend clamp load, scale back deflection and maximize seize life.

Key Features

• Increased clamp load for higher torque capacity
• Street-friendly organic sprung disc design
• Improved heat resistance under aggressive driving
• Durable construction for long-term use
• Precision-engineered components

All diaphragms endure an exclusive four-stage, heat-treating process for unparalleled performance. The Heavy Duty pressure plate meets SFI Specification 1.1. ACT Performance Street discs are modified with reduced marcel for faster shift action to counterpoint ACT pressure plates.

Performance Benefits

• Eliminates clutch slip under load
• Improves engagement and power transfer
• Handles moderate performance builds
• Maintains daily drivability

No slipping. No drama. Just holds power like it should.

Performance Street discs have higher copper content friction lining for heat tolerance and steel-backed lining for greater burst strength and durability. Also, they feature top grade rivets to soundly fasten the part together.

⚠️ What to Expect

• Firmer pedal feel vs OEM
• Slightly more aggressive engagement
• Still comfortable for daily driving

Translation: noticeable upgrade—not annoying.

Installation Notes

• Resurface or replace flywheel (highly recommended)
• Follow 500–750 mile break-in period
• Inspect:
  • Hydraulic system
  • Rear main seal
• Ideal install during:
  • Performance upgrades
  • Clutch replacement

The rivet design and rivet materials are carefully selected for maximum strength. ACT spring-centered assemblies use bushings and cone springs very similar to factory seize discs. This creates frictional dampening, which improves seize life and reduces noise. All Performance Street discs are certified as meeting SFI Specification 1.1 and are legal in all racing organizations that require SFI certification. The kit is completed with a quality, stock replacement release bearing, pilot bearing and alignment tool.

A low to moderate pedal feel; smooth engagement with stock to low gear rattle
Longer seize life achieved through ACT’s exclusive diaphragm design
Premium organic friction materials for heat tolerance, faster recovery from overheating and prevents warping of mating surfaces
Advisable for street and race use
All ACT pressure plates are dynamically computer balanced for smooth operation at high RPM

Why ACT ZM1-HDSS clutch?

Because ACT:

• Specializes in performance clutch systems
• Is trusted across track and street builds
• Delivers real torque-holding capability without sacrificing usability

Final Verdict

The ACT ZM1-HDSS Clutch Kit is the perfect upgrade for RX-8 owners—stronger, more reliable, and built to handle real driving without ruining your daily.

Finally gives your rotary something that won’t tap out first.