Which race clutch setup ?
 

I am looking to upgrade my clutch setup, and wondering what is the target clutch setup for my application.

Application is wheel-to-wheel endurance racing, with 2000 lb Miata making less than 130rwhp with 94-95 1.8L motor.
I don't intend to advance the car significantly from it's specs from here. So, no significant change in power. Changes would be like Improvements in aerodynamics, traction, some weight reduction, gear change one step.

Currently running a Fidanza aluminum flywheel for 1.6L motor, and stock-ish clutch disk. Having no issues over last 5 races, about 100hours on race track.
Now I'm looking to move up to next level or target level for my application. I looked over a couple of threads regarding the smaller clutch setups from members.
Maybe there is some insight from their experiences that could provide guidance and recommendation for my application.

7.25 clutch with steel flywheel
7.25 clutch with aluminum flywheel(could have some heat management issues unless careful with slippage?)
5.00 clutch and steel flywheel(will always require being careful with slippage?)

Also, I am seeing some single disk setups in the 7.25 clutch. Is that just a no-no for my application?

Is there a vendor for button flywheels?

On a related note, when I was drag racing late model Camaros long ago, I moved from a 6speed manual to a 3speed auto, then to a smaller/lighter 3speed auto, then to a 2speed and found the target for my application.
I should have just skipped over the pair of 3speed autos, and went to the 2speed and not wasted the time and money with the 3speeds. All with the same car specs.

Wingnut

I would stick with your stock-ish clutch. Any of the 7 1/4in. or smaller Tilton type clutch's are pretty much on-off switch-like action. Very hard to drive thru the pits, or on street. They are usually always solid riveted , un-sprung plates, so you have to up the rev's, quickly slip out the pedal, or stall your car. The advantages; less mass, higher torque capacity, quicker rev's are offset by the harder drivability IMO. Your HP levels do not require anything beyond stock. I am currently running the stock Exedy 1.8 clutch in my boosted 1.6. It holds perfectly with 186RWP. I will upgrade next year, when the BP4W goes in, but until then it will be fine.

Supermiata twin disc or the tilton twin disc. Both are very good. I might know a guy with a tilton 7.25 for sale with 2 boxes of spare plates for it.

There's your easy button

matrussell122, sent you a pm.

Wingnut

Really like my Supermiata twin disk with the 5.5lb flywheel.
Enough modulation to get it in the trailer and around the paddock.
Also reduces shift time, so there is a lap time reduction based on the number of upshifts/lap.

I have used Racing Beat or MazdaTrix sourced 4 puck clutches in my street ported RX7 for years and years. They never wear out, they accept hard fast shifting, and add only modestly more force to the shift pedal. With multiple drivers in endurance racing they are a very good bet. I occasionally used a stock RX7 clutch when racing and burned them out within 2 days, probably from hard shifting with rapid return to WOT.
(The street port with stock carb made 135 hp at the wheels and ~ 100 ft-lb of torque, so similar torque to the 1.6 L, but a bit higher hp.)

Racing Beat sells an Exedy 3 puck kit at a respectable price for the Miata.
Exedy Stage 2 Clutch Kit for 90-93 Miata - Racing Beat

100% agree on Supermiata twin clutch setup. the light flywheel and clutch setup is MAGIC to drive. Get the fibre plates thought. The metal/ceramic or whatever they are are a curse for trailer, road etc.

The fibre was out of stock when we purchased so used it until the fibre arrived. Nigh and day different.

Though I do think at 300 HP or so it contributed to our spate of gearbox failures.

At your power levels that wont be a issue at all.

Our car was THE most fun to drive when it ran that setup.

Maybe it's because I've been using a metal-disc 949 twin for ~10yrs, but I don't find it difficult at all to modulate. I've done a couple dozen standing race starts with it and I drive the car on/off the trailer and I can't remember the last time I stalled it. It takes a little more RPM and a little muscle memory, but do it for a weekend and you'll have it figured out. It's a price worth paying for a clutch that will literally never wear out.

Thanks fella's. This kind of info is what I need to get a better understanding before sending in the monies.

Sounds like the 7.25 twin is definitely a step in the right direction for my track only car.

Last thing to consider is, if the 5.5 is a net benefit(after getting accustomed to it) for my setup over the 7.25 .


Wingnut

We occasionally get customers asking how long our ceramic twin will last. Our answer is that we don't know as no one has ever worn one out that we know of.

The Super miata twin clutch is now banned/lots of points in Champcar, so I have one for sale if you are interested. It was a great combo with carbon kevlar disks.