ACT 1991 Mazda Miata XT/Perf Street Sprung Clutch Kit
ACT ZM2-XTSS is a street clutch for an NA or NB Mazda Miata that has outgrown the factory clutch but still needs to be pleasant on the drive to work. Owners usually find it after a turbo kit, supercharger or tune: the car slips in third when boost arrives, the clutch smells hot after a track day, or the pedal engagement point keeps moving up. This kit combines ACT's Xtreme pressure plate with a full-face organic disc, so it holds far more torque than stock without the on-off bite of a puck disc.
In the Miata the clutch bolts to a flywheel on the back of the longitudinal four-cylinder and feeds the five-speed, or the six-speed in some later NB cars. The release system is hydraulic: the pedal pushes fluid from the master cylinder to a slave cylinder on the bellhousing, which moves the fork and bearing. ZM2-XTSS uses the MZ012X Xtreme plate, whose diaphragm ACT designs for higher clamp load and less deflection at high rpm. It clamps ACT's 3000203 Performance Street sprung disc, a 224 mm (8.8 in) organic facing with high copper content and a steel backing. ACT rates the kit at 315 ft-lb at the crank, 76 percent over the factory clutch, and lists the input shaft at 0.9375 in.
ACT describes the feel as moderate to heavy pedal, smooth engagement and OE to mild gear rattle. That makes it a strong match for a boosted street Miata. Cars making serious track power can step up to the ZM2-XTG6 Xtreme six-pad race kit, while a lightly modified car may prefer the lighter pedal of the ZM2-HDSS heavy duty street kit.
A Miata hydraulic fault can look like a worn clutch, so check the system first. Look for fluid at the slave cylinder boot, check the reservoir level, and confirm the pedal returns fully. A slave that will not let the fork return keeps the bearing pressed on the fingers and causes slip. Then road test in fourth from about 2,500 rpm at full throttle; if rpm climbs faster than speed, the disc is slipping. Check the bellhousing for oil from the rear main seal, since oil on the new facings will make it slip again. The slipping diagnosis guide covers these tests step by step.
Our title says 1991, but ACT's chart lists ZM2-XTSS for every NA and NB Miata from 1990 to 2005: the 1990-1993 1.6L cars and the 1994-2005 1.8L cars, including the 1999 10th Anniversary and the 2004-2005 Mazdaspeed. It does not fit the 2006-up NC or later cars. The early 1.6L cars originally had a smaller clutch and flywheel, and our ACT Miata flywheel listings state that 1990-1993 cars must use the 1.8L-size clutch with those flywheels. On a 1.6L car, confirm which flywheel is fitted before ordering, and send us your year and VIN if you are not sure. More Miata clutch parts are in our rebuild kits collection.
| Brand | ACT |
| Part number | ZM2-XTSS |
| Fits | ACT 1991 Mazda Miata XT/Perf Street Sprung Clutch Kit |
| Vehicle fitment | Mazda Miata Xt/Perf (1991) |
| Type | Clutch Kits - Single |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
Yes. ACT lists it for 1990-2005 Miatas, which covers the 1999-2005 NB cars including the Mazdaspeed. It does not fit the 2006 and later NC. Send us your VIN if the car has had drivetrain swaps.
ACT lists the 1.6L cars on its application chart. The 1.6L originally used a smaller clutch, and ACT's Miata flywheels require the 1.8L-size clutch on those years, so confirm what flywheel your car has before ordering. If you are unsure, send us your year and VIN.
ACT rates ZM2-XTSS at 315 ft-lb of torque capacity measured at the crank, 76 percent more than the factory clutch. That covers most street turbo and supercharger builds. For more than that, look at the ZM2-XTG6 six-pad race kit.
ACT expects 50 to 80 percent more pedal effort with an Xtreme plate, depending on the car, and describes the feel as moderate to heavy. Healthy master and slave cylinders make a big difference to how it feels.
The Miata clutch hydraulic system runs on brake fluid. Use fresh DOT 3 brake fluid from a sealed bottle and bleed the slave cylinder after the clutch is installed.
The kit does not include one. At minimum have the flywheel resurfaced. If it is cracked, blued or below minimum thickness, replace it; ACT's Streetlite and Prolite flywheels are the lighter options for these cars.
