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For sale is a used SPM 5.5lb (race) clutch and flywheel. I pulled it out of my TT car after 3 seasons and probably <100 street miles. I'm going back to a more street-friendly Supermiata 1.8 sport clutch, with the intention of using it for my K24Z swap I'm slowly piecing together. Clutches and friction surfaces are all in good condition.
Depends on whether or not it's a track car that you sometimes drive on the street or if it's a street car that you sometimes drive on the track.
Will be leaning towards track car this time around... I've ridden in a Supra that was a triple disc that was awful, mainly because you could not slip it at all so was easy to stall and hard to be smooth at slow speeds.
Sorta want, how bad is it really on the street? I've contemplated getting one many times. But I intend to still drive on street...
Just about anything can be driven on the street, but I would hate to commute with it. Everything that makes it beautiful on track makes it a hassle to drive on the road.
Clutch pedal really isn't heavy. I don't even notice the weight. The main drawbacks for street driving are:
The NVH (mainly in overrun where the unsprung hubs transfer a bunch of vibrations to the driveline and it sounds a lot like straight cut gears)
It's basically a binary switch (which you expect from a twin disk), but I can slip it enough to drive it into the trailer. It just takes concentration once you get near the friction point to not stall it, but you don't need to give it a boot full of revs to get it off the line. You can start on flat ground without touching the throttle.
The revs just drop too quick when you're just putting around. I actually blip the throttle on my upshifts if I'm shifting at like 3 or 4k and not trying to bang shifts because the revs drop too low too quickly to rev match the next gear.
On the flip side on track I can shift basically as quickly as I can grab the shifter and find the next gear. And the blips for the downshifts are equally as snappy. I've decided to ballast up to 2450lbs this year, so I figured I'd throw the carpets and window regulators back in and actually have something I'd drive a bit more on the street if the clutch was a bit more civil.
Bumping my post. I’m at 23lbs for my ACT 4 puck unsprung setup but already taking points for modified clutch and flywheel so see if there is more to gain with this setup.
Bumping my post. I’m at 23lbs for my ACT 4 puck unsprung setup but already taking points for modified clutch and flywheel so see if there is more to gain with this setup.
Total weight of clutch and flywheel w/ pilot bearing and pressure plate bolts is 15.2lbs
There's also the fact that my combo is a conventional clutch at the same ish weight (16lbs) but the MOI on a twin disc is so much better that it revs completely different from mine. There is definitely more to gain with this over a conventional single plate clutch. All of the mass is concentrated at the center.
Bumping my post. I’m at 23lbs for my ACT 4 puck unsprung setup but already taking points for modified clutch and flywheel so see if there is more to gain with this setup.
We modeled the BP and our twin in CAD and did a basic MOI study. It's a massive difference to even the lightest BP clutch/flywheel combos.
BP flywheel has the large posts around the perimeter of the friction surface, far from the center. That raises MOI. The twin has a much smaller friction surface/material which lowers MOI. Where the BP flywheel has posts, our twin design has a lightweight web, more air than metal.
02-15-2022, 09:28 PM
FS: Supermiata Twin Disk 5.5lb Race Clutch - Used
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