The ACT ZM1-HDG4 Heavy Duty Race Sprung 4 Pad Clutch Kit pairs ACT's most popular Heavy Duty pressure plate with a 4-pad spring-centered race disc. The Heavy Duty pressure plate uses an exclusive diaphragm design to increase clamp load and reduce deflection for longer clutch life, and every diaphragm goes through ACT's four-stage heat-treating process, with precision cover stampings adding rigidity and consistency. The 4-pad spring-centered race disc dampens torsional vibrations for quieter operation and resists failure under harsh use; wraparound spring windows and thicker retainer stampings on the spring retainers add support and reduce stress concentrations for increased strength. Engagement is harsher and shifting is faster than with a street disc, and the smaller 4-pad configuration is best suited to smaller disc sizes on smaller-displacement engines.
WarrantyInstallation Instructions
Specifications:
- Pressure Plate: ACT Heavy Duty, four-stage heat-treated diaphragm
- Disc: 4-Pad Spring-Centered Race Disc
- Hub: Spring-centered for torsional damping
- Includes: Pressure plate, 4-pad race disc, alignment tool (pilot bearing and release bearing included on some applications)
- Recommended Use: Race use, smaller clutch/disc-size applications
- Part Number: ZM1-HDG4
Vehicle Applications:
- 1990 Mazda Miata Base
- 1991 Mazda Miata Base
- 1991 Mazda Miata SE
- 1992 Mazda Miata Base
- 1993 Mazda Miata Base
- 1993 Mazda Miata LE
Warning: This product can expose you to chemicals including carbon black, glass wool fibers, or silica (in clutch discs), chromium and nickel, which are known to the State of California to cause cancer or birth defects or other reproductive harm. For more information, visit www.P65Warnings.ca.gov
FAQ
What makes the 4-pad race disc different from a 6-pad race disc?
The 4-pad spring-centered disc uses fewer, larger friction pads and is sized for smaller clutch diameters on smaller-displacement engines like the Miata's, while 6-pad discs are reserved for larger clutch sizes that need to absorb more heat.
Will this kit have a harsher engagement than a stock clutch?
Yes. The race-sprung disc trades some street comfort for harsher engagement and faster shifting, which is expected with ACT's Race Sprung product line.
Does the kit include a pilot bearing and release bearing?
Pilot bearing and release bearing are included on applications where the vehicle requires them.
Does this kit fit the 1993 Miata LE?
Yes, the ZM1-HDG4 covers the 1990-1993 Miata Base along with the 1993 LE and 1991 SE trims.
