ACT 2007 Mazda 3 HD/Race Sprung 6 Pad Clutch Kit
Mazdaspeed3 owners usually start shopping for a clutch the week after a turbo upgrade or an aggressive tune: the car pulls hard in 2nd, then the tach jumps in 3rd and 4th while the car does not. The ACT ZX4-HDG6 is ACT's Heavy Duty plate paired with a sprung 6-pad ceramic disc and an XACT Prolite flywheel, rated at 574 ft-lb at the crank, 93 percent more than the factory clutch. Although our listing title reads 2007 Mazda 3, this kit is for the turbocharged Mazdaspeed models, not the regular non-turbo Mazda3.
The 2.3L DISI turbo engine (MZR) makes a broad wave of torque that the stock clutch was only sized to handle at factory boost. ACT's MZ031 Heavy Duty pressure plate raises clamp load with its own diaphragm design, and the 240 mm disc (6240508-2) swaps the full organic face for six ceramic pads that take more heat before fading. The disc keeps a spring center, so torsional vibration is still damped and ACT describes gear rattle as OE to mild. The 600521 Prolite flywheel is the lighter of ACT's two Mazdaspeed flywheels, so the engine revs up and drops faster between shifts. ACT calls this a conversion kit; the Prolite flywheel is required with this plate.
Do a controlled load test in 4th gear from low rpm and watch whether engine speed outruns road speed. If it does, check the hydraulics next; a weak slave cylinder or a pedal that does not fully return can leave the clutch partly disengaged. Rear main seal or transmission input seal leaks can soak a disc, and a new clutch will slip again if the leak is not fixed. Our Mazdaspeed3 clutch replacement and upgrade guide covers the common failure pattern, and the slipping diagnosis guide walks through separating slip from other problems.
ZX4 kits use the Prolite flywheel and ZX5 kits use the heavier Streetlite. If the car is a daily driver with a moderate tune, the organic ZX4-HDSS street kit on the same flywheel is smoother in traffic. For big-turbo builds that need more than 574 ft-lb, ACT's Xtreme plate version, the ZX4-XTG6, steps up holding power at the cost of a heavier pedal. The HDG6 sits in the middle: ACT lists light to moderate pedal effort and aggressive engagement, recommended for high horsepower street or race use.
ACT lists ZX4-HDG6 for the 2007-2013 Mazdaspeed3 and the 2006-2007 Mazdaspeed6, both with the 2.3L turbo and 6-speed manual. It does not fit the naturally aspirated Mazda3 or Mazda6. The input shaft diameter is 1 in. If you have a swapped engine or gearbox, or you are not sure which car you have, send us the year and VIN and we will confirm before shipping.
The MZ031 pressure plate and 600521 Prolite flywheel are also sold separately if you are rebuilding an existing ACT setup.
| Brand | ACT |
| Part number | ZX4-HDG6 |
| Fits | ACT 2007 Mazda 3 HD/Race Sprung 6 Pad Clutch Kit |
| Vehicle fitment | Mazda 3 Hd/Race Sprung 6 (2007) |
| Type | Clutch Kits - Single |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
No. ACT lists it for the turbocharged 2007-2013 Mazdaspeed3 and 2006-2007 Mazdaspeed6 only. The non-turbo Mazda3 uses a different clutch.
ACT rates it at 574 ft-lb measured at the crank, 93 percent over the factory Mazdaspeed clutch.
ZX4 kits include ACT's lighter XACT Prolite flywheel (600521). ZX5 kits include the XACT Streetlite flywheel, which carries more mass and is a bit friendlier pulling away.
Yes. ACT calls this a conversion kit and includes the Prolite flywheel, which must be used with the MZ031 plate. Pressure plate bolts are supplied; plan on new flywheel bolts.
The 6-pad ceramic disc engages more abruptly than stock, but the sprung hub keeps gear rattle at OE to mild levels according to ACT. Expect a short learning curve on takeoff.
Look for rear main seal and input seal leaks, inspect the slave cylinder and clutch line, and refill the gearbox with fresh Mazda-specified manual transmission oil.
