ACT 2004 Mazda RX-8 HD/Race Sprung 6 Pad Clutch Kit
The ACT ZM8-HDG6 is the clutch RX-8 owners reach for once the Renesis rotary is making more than the factory clutch was meant to hold: a turbo or supercharger conversion, a track car that sees lap after hot lap, or a driver who launches hard at the drag strip. It pairs ACT's Heavy Duty pressure plate with a spring-centered, six-pad ceramic disc. If your RX-8 slips at high rpm in third or fourth, smells hot after a session, or glazed its last organic disc, this kit is built for that job.
The RX-8 runs a conventional single-disc clutch between the 1.3L two-rotor engine and the manual gearbox. A rotary spins high and delivers its torque near the top of the tach, so the clutch sees long, heat-heavy engagements on track rather than big low-rpm shock. ACT's MZ010 Heavy Duty pressure plate uses a four-stage heat-treated diaphragm to raise clamp load and limit deflection, and the 6240208 disc puts six ceramic pads on a 240 mm (9.4 in) sprung hub with a 1 in input. Ceramic shrugs off heat that would fade an organic facing, and the hub springs still damp torsional vibration so the gearbox is not hammered on every shift.
ACT rates the kit at 420 ft-lb at the crank, 72 percent above the OE clutch. The cost of that capacity is engagement: ACT describes it as aggressive, with harsher take-up but faster shifts, and expects pedal effort to rise roughly 15 to 40 percent with a Heavy Duty plate. It is meant for high-horsepower street or race cars, not a stock RX-8 that lives in traffic.
Rule out the hydraulics first. A low reservoir, a leak anywhere in the clutch hydraulics or air in the line can leave the clutch partly applied or partly released, which mimics slip and grinding. Then do a full-throttle pull in fourth from mid rpm on a safe road: if the revs flare ahead of road speed, the disc is slipping. Our slipping diagnosis guide walks through that road test, and shift flare vs. slip explains why a quick rev rise between gears is not always the clutch. If the pedal is fine but the car will not go into gear, read our clutch won't disengage guide before you order parts.
Our listing names the 2004 RX-8. ACT's application table for ZM8-HDG6 covers every North American RX-8 year from 2004 through 2011, including the Base, Shinka, Sport, Touring, GT, Grand Touring, 40th Anniversary and R3 trims, all with the 1.3L Renesis. Rotary builds and gearbox swaps are common in this chassis, so match your old pressure plate and disc before you order, or send us your year and VIN and we will check it. Browse more RX-8 clutch and flywheel parts in our rebuild kits collection.
For a street car with mild bolt-ons, the organic ACT ZM8-HDSS uses the same pressure plate with a smoother disc rated at 330 ft-lb.
| Brand | ACT |
| Part number | ZM8-HDG6 |
| Fits | ACT 2004 Mazda RX-8 HD/Race Sprung 6 Pad Clutch Kit |
| Vehicle fitment | Mazda Rx-8 Hd/Race Sprung 6 (2004) |
| Type | Clutch Kits - Single |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
ACT lists it for all 2004-2011 North American RX-8 models with the 1.3L Renesis rotary, across trims from Base to R3. Send us your year and VIN if the car has a swapped gearbox or engine.
No. It includes the pressure plate, 6-pad sprung ceramic disc, release bearing, pilot bearing and alignment tool. Resurface your stock flywheel or pair it with the ACT 600145-03 Streetlite flywheel and CW03 counterweight kit.
ACT states that its XACT flywheels must be used with the ACT counterweight on RX-7 and RX-8 rotary applications, so a lightweight flywheel is sold as a kit with the CW03 counterweight. Do not install an aftermarket flywheel without it.
It works, but engagement is aggressive and some chatter on takeoff is normal. For a stock or lightly modified daily driver the organic ZM8-HDSS is the more comfortable choice.
ACT expects 15 to 40 percent more pedal effort with its Heavy Duty pressure plates, depending on the application.
ACT says its race discs only need a few hard slips to lap in the friction surfaces. Do not overheat the clutch while it beds in.
