6 replies to this topic

[Chris Wilson]

I am turbo charging a Toyota Formula Atlantic engine in my Zeus Supersports car. It currently runs a 5.5 inch twin plate sintered Tilton clutch on a lightweight steel flywheel with integral ring gear. I suspect the flywheel may also be a Tilton product, but I didn't spec or build the engine, so don't know for sure, it has no apparent branding on it. I doubt this clutch will like the added torque i hope the turbo will bring, so am looking at either a 5.5 inch triple plate sintered, or just maybe a twin plate carbon clutch from Tilton, Alcon or AP. I have never used a carbon clutch, would it be possible to run one on the existing flywheel?

I have an Alcon concentric release bearing on an extension tube off of the gearbox (Hewland FTR), which I could re make shorter, to give correct bearing placement, and I THINK I have enough spline length on the input shaft for a triple plate, but the latter is one reason I am considering a carbon clutch. Thanks.

[J. Edlund]

A carbon/carbon clutch doesn't use the flywheel as a friction surface, so there are not really any specific demands put on the flywheel by the clutch other than that it must be possible to attach the clutch to the flywheel, to the input shaft of the gearbox or directly to the crankshaft. The question is if you can find a suitable c/c clutch, and if you can't ,it's probably cheaper to use an off the shelf c/c clutch and modify the flywheel or make a new flywheel that fits the clutch.

[Chris Wilson]

I think I am going to go with a sintered 2 plate and up the pressure plate to a heavier clamp pressure unit and see what happens. If I need to have more torque capacity still I may have to both up the input shaft diameter and, with it being a different shaft, spec it to accommodate a triple plate unit or a complete carbon / carbon package. Still open to ideas though, a fair way off buttoning this thing up Thanks.

[Stefan_VTi]

What about kevlar for friction material? I had one in my car and it worked pretty well for me. Supposed to have a higher Cf at elevated temps, requiring less clamping force. Also worked with a steel (so regular) countersurface on the flywheel.

[jrobson]

What about kevlar for friction material? I had one in my car and it worked pretty well for me. Supposed to have a higher Cf at elevated temps, requiring less clamping force. Also worked with a steel (so regular) countersurface on the flywheel.

Carbon has a very high coefficient of friction, it's quite an interesting material, for instance if you put the total plates from a 5.5" tripple disc clutch on top of each other, the only thing holding being the weight of the carbon plates themselves, which is very little, you can not slip it by using your hands, this I think is why they say the brakes are very on-off in cars fitted with them, it requires little pressure to exibit high friction, the friction coefficient is very high even if the surface is a bit worn and polished/glazed over! The only drawback to CC is the cost, but the 115mm units can be made for around $1000 or so.

Edited by jrobson, 02 June 2009 - 19:31.

[gruntguru]

You can estimate the torque increase as being proportional to absolute boost pressure i.e. 1bar boost (2bar absolute) = 2 x NA torque, 2bar boost (3bar absolute) = 3 x NA torque etc

[TOAD]

You can estimate the torque increase as being proportional to absolute boost pressure i.e. 1bar boost (2bar absolute) = 2 x NA torque, 2bar boost (3bar absolute) = 3 x NA torque etc

Hi, I was speaking to AP about C/C clutches, and they said one of the drawbacks is that it would need adjusting and re setting up allot.

Regards