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Sport Clutch Kit
Miata MX5 BP 1.8 engine
Organic Torque capacity 290ft/lbs – Organic has OEM like smooth modulation and driveability but with greater torque capacity.
Puck (Ceramic/Metallic) Torque capacity 340ft/lbs – The ceramic material does not modulate as quite as smoothly as organic, but still daily driveable. Choose puck type if you need more torque capacity than the organic can deliver and are willing to sacrifice a little smoothness to get it.
Rigid hub option Not recommended for street due to the significant increase in noise, vibration, harshness (NVH) from the transmission. This option deletes the sprung hub center of the disc, saving about 1lb. The benefit is quicker shifting and sharper power transfer for racing only.
The USA designed and manufactured Supermiata clutch kit has been developed during two years of racing and street use. We added clamp load to increase torque capacity without sacrificing light pedal effort.
The construction is the most durable on the market for this torque capacity.
The stock Miata clutch requires roughly 20 lbs of force to depress depending on the year. That is very light. A child can drop the OEM pedal with ease. The Supermiata Sport clutch is in the 35 lbs range. This is still light enough to be flicked with your forefoot during fast shifts. By comparison, our monster twin disc 7.25 Raceclutch is close to 60 lbs.
All clutches are not created equal
They all look about the same right? Most aftermarket clutches sold in the US are made in China. There are many world class quality products coming form China (your smartphone!) but clutches don’t seem to be one of them. That is why the Supermiata Sport Clutch is assembled in the US from US, Japanese and Korean components. We test each and every batch of clutches for clamp load. There are many unseen details that make a superior clutch assembly. Read on.
Pressure plate – Many clutches use inexpensive “gray” iron pressure plates. Besides having a less than ideal friction coefficient, gray iron is weaker and more prone to warping. Nodular iron in our clutch is more expensive to make but far stronger and increases torque capacity.
Ball bearing fulcrum – The pressure plate features a circular row of embedded ball bearings that reduce pedal effort required. This in turn allows us to up the clamp load which increases capacity.
Diaphragm spring – There are two ways to get an increase in clamp load, thicker diaphragm spring or heat treating. Thicker spring costs less, makes for a much heavier pedal that usually disengages at the floor and also gives the clutch an “over center” or cam like feel where it’s more difficult to modulate. A non heat treated spring will also wear out faster. Heat treating allows the use of a much thinner spring that is, well, springier. This provides the increase clamp load for greater holding power without the heavy pedal as well as a nice progressive action. Heat treating doubles the cost of manufacturing the diaphragm spring and it’s how every Supermiata clutch is made.
One piece drive plate – Some clutch manufacturers use mix n’ match multi piece drive plates to reduce tooling costs for each application. We don’t. Our drive plate is a one piece, proprietary stamping to increase strength, used just for our clutches.
Straps – These are the flexible straps that hold the pressure ring to to the cover. Most OEM replacement clutches use a single thin gauge strap. Fine for a daily driver but those small straps can weaken and fail under extreme torque loads. That’s why our clutch uses a extra width double strap system.
Hubs – Our 4140 steel hubs are both heat treated and shot peened for strength. The shot peening can be seen by the slightly textured surface of the hubs. Does your old hub look this way?
Drive hub rivets – Look around and you will see most 1.8 Miata discs use 4 rivets to hold the two halves of the disc together and transmit torque. Supermiata discs use 6 rivets. This increases surface area to transmit torque on the sprung hub by 50%
Cover – They all look alike right? Nope. Many Chinese sourced clutches use thinner gauge than OEM covers that work ok at OEM power level on a daily driver but will distort and cause problems under continued use with high torque/heat. You guessed it, we use heavier than OEM gauge covers. Every batch gets tested for clamp load to verify heat treating.
So you can see, there is much more than meets the eye with aftermarket clutches and it’s why it took us a few years to release our SuperMiata clutch. Many of the features of the Supermiata Sport clutch are not discernible to the untrained eye. These features, almost without exception, cost more to manufacture than other similarly priced clutches on the market. We work hard to bring the highest possible quality and cutting edge feature set at a competitive price. The same innovation, attention to detail, and intolerance of equipment failure that won us several 24hr races and 6 national championships is put into every component we develop for your car.
- Double, extra wide straps on pressure plate
- Heat treated diaphragm
- Shot peened and hardened disc hub
- Nodular iron pressure ring
- Ball Bearing diaphragm fulcrum for reduced effort/increased capacity
- One piece drive plate
- Steel backed, bonded, riveted construction on organic version
- 6 rivet disc drive hub
- Designed and assembled in the USA from USA and Japan manufactured components
- 50% increase in clamp load
- Weight 10 lbs 9 oz for pressure plate & organic sprung hub disc
1x Clutch cover/pressure plate
1x Clutch disc
1x Exedy pilot bearing
1x Exedy release (throw out) bearing
1x Alignment tool
The original protoype Sport Clutch won the grueling 25 hours of Thunderhill in Team 949 Racing Miatas in 2011, the longest endurance race in the world. We now use it in our back to back championship winning Supermiata where every race weekend has 4 standing starts on hot race tires. That is abuse! You’re not going to break it, plain and simple. If you do, we replace it free of charge. Forever*
* Limited lifetime warranty against breakage of disc or cover assembly. Does not include normal wear or damage due to improper usage, installation or application
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