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The mkiv Supra Owners Club

opinions on clutches


eyefi

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Originally posted by eyefi

how do u (if indeed u can) launch triple plate clutched cars on boost?

 

whats the best type of (sprung) clutch for getting good launches, bearing in mind keeping keeping it light?

 

ta.

 

Unless the car will make boost in neutral you can't. Stock turbos will make some positive pressure. NOS will do the trick, especially with an ignition retard device (after market ECU required)

 

I don't know of any really light SPRUNG plated triple plate clutches. If you want light weight you need something like

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Chris,

 

Was that off your old RX7?

 

I asked AP about clutches and flywheel combo's and they just said they didn't do any. Which was helpful.

 

How much would it cost for a person off the street to get them to make up a clutch and flywheel kit to hold about 500lb/ft on a 5.5" twinplate, with a 4-5kilo flywheel?

 

What is the ball park on getting a whole new clucth system with different cylinder and therefore the ability to customise the feel and effort? Or is that not possible?

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looks good for hill starts, very savage :) what r all the spikes for around the edge?

 

one reason im asking is, ive seen folk launch (with launch control) at high revs, slip the clutch until it moves then close the clutch completely. i just dont see how this could b done with something like a triple plate, which dont like to slip.

 

the other reason i ask is, why dont the turbos provide any boost when the engine is not under load? is it a physical reason(not enough gasses - but there should be the same under load or no load) or an electrical reason (ecu control - opens wastegate when no load).

 

ta

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Originally posted by Alex Holdroyd

Chris,

 

Was that off your old RX7?

 

I asked AP about clutches and flywheel combo's and they just said they didn't do any. Which was helpful.

 

How much would it cost for a person off the street to get them to make up a clutch and flywheel kit to hold about 500lb/ft on a 5.5" twinplate, with a 4-5kilo flywheel?

 

What is the ball park on getting a whole new clucth system with different cylinder and therefore the ability to customise the feel and effort? Or is that not possible?

 

AP don't do any flywheels as such. 1st you need to get a chrome moly flywheel made up, for ease using the stock ring gear. to get down to the target weight it will need windowing like the one I did for my RX. Then balancing. No worries about the torque handling. You will have to use unlightened plates, the clutch in the picture is an F3 titanium one, mega money, and won't last long with drilled plates and 500 ft lbs! For longevity a triple plate would be better, and not a huge amount dearer. You then need a concentric release mechanism, i made one for a Volvo a bit ago, may still have photos. The stock system pulls, you want one that pushes.

 

Absolute top of my head figure of 1500 quid. As a one off this stuff is pricey, but set up to make say 10 flywheels and 10 release cylinder set ups and it comes down a lot. Tilton do AP copy clutches that are pretty much the same thing, but a good deal cheaper. A none sprung clutch with none damped light flywheel will cause hellish gearbox noise, BTW. To go sprung centre plate you need 7.25 inch clutches.

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This is what you need to operate a conventional cluth without levers and messing around. This release is similar to one thet Tilton make, about 200 quid I think, as a basic kit, plus machining. The Volvo to Getrag bellhousing here lent itself to an easy conversion, I did a dummy fit and the machining in an afternoon, with engine and box out of course.

concentric.jpg

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Originally posted by eyefi

looks good for hill starts, very savage :) what r all the spikes for around the edge?

 

one reason im asking is, ive seen folk launch (with launch control) at high revs, slip the clutch until it moves then close the clutch completely. i just dont see how this could b done with something like a triple plate, which dont like to slip.

 

the other reason i ask is, why dont the turbos provide any boost when the engine is not under load? is it a physical reason(not enough gasses - but there should be the same under load or no load) or an electrical reason (ecu control - opens wastegate when no load).

 

ta

 

A double or triple or quadruple plate clutch WILL slip, but it generates insane heat. Carbon / carbon clutches are better for this as they will recover, but they still damage the heat treat of the flywheel and gearbox input shaft. Not into drag racing, so unsure what the current stae of play is, I think they still use a cemtrifugal clutch engagement though using different fly weights on the cover. A specialised clutch set up by specialists.

 

Turbos need more gas speed and volume, only available under load, or by specialised trickery.

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If you're talking Supras in drag racing, then the Carbon-Carbon clutches are what they're all excited about at the moment. Meant to be very streetable as well if that's a concern. I've heard people use a two-step rev limiter to build boost on the line; I'm not quite sure how this works but I'm told it does.

 

Top methanol and top fuel dragsters are a whole different kettle of fish; they use sophisticated mulitplate clutches which gradually release over the quarter, fully engaging at about 1000ft I think. The idea is that the driver can go pretty much full throttle, and the counterweights on the clutch do the job of feeding in the power as quick as possible, but still keeping traction. Neccessary because you wouldn't be able to slip a clutch which can hold 6000bhp on enormous slicks!

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