Clutch disc for circa 150bhp

As above - what are people’s experiences with clutch discs for the twincam with around 150 bhp for use in a road car?
Best brands / spec etc. I’m thinking of using 8.5" but I might consider 8".

I use an Excedy 8.5 inch clutch plate good for up to 180 hp plus with a AP pressure plate. The one i use is from a Mitsubishi Evo. Dont have the part number currently as travelling

cheers
Rohan

Use as small a clutch plate as you can get away with. The bigger the clutch plate the more the synchronisers have to work to synchronise gear speeds. Shifts will be slower and more notchy. Torque and gear ratio matters more than HP. The 5 speed needs a bigger clutch because of the taller top gear.

I am in the process of choosing a new clutch myself, so this is a helpful conversation.

I get that torque is what matters for a clutch, not HP, but I don’t understand what gear ratios have got to do with it?

Cheers Rohan, will have a look around. Are you using the 4 speed gearbox ie 7/8"x20 spline?

Cheers, here’s the potential fly in the ointment - if things work out I will be using a Lotus 3 rail 4 speed box that has an overdrive 4th gear (that’s not a mis-type!) through some old school engineering so would want to use a disc that responds well to that.
I will likely use a 3.5 diff so there’s also that to consider.

The taller the gear ratio the more resistance there is to getting things to start moving hence the loading on the clutch increases. When you have a worn clutch you’ll notice that it slips more in the higher gears than in lower ones. This is the reason why.

Yes standard 4 speed box and spline

Cheers. Is this your race car?

Yes my race car but perfectly suitable for road use.

found a photo of the clutch on my phone the numbers on it should help identification

cheers
Rohan

That’s great, thanks Rohan. Not found anything on those numbers yet but will keep looking. Hope you are enjoying your travelling.

Do you know if the 8" is fitted to your escort twincam?

Yes the Twin Cam Escort has the 8” clutch plate as standard. The standard pressure plate can also accommodate an 8.5” plate however. Hard to get an 8” clutch plate these days - although I do have a NOS one stashed away somewhere.

Interesting about that Exedy clutch plate. If you Google the numbers you find it’s out of a mid 70’s to 80’s Mitsubishi Colt / Lancer grocery getter and not a high performance Mitsubishi. That doesn’t mean it’s not OK to use however. 8,000 RPM might be a bit scary but if it’s been done it’s been done.

Thanks for the details. I ran a Lotus flywheel and clutch with a 8.5" disc from a sierra on a crossflow paired to a type 9 gearbox in a mk2 escort a long time ago and it worked well. Surprisingly the damper coil springs seemed to match the characteristics of the engine / car and it was barely worn when I took it out 10,000 miles later.
Keep hold of that NOS item, even if tempted to sell it as it’ll be sod’s law you need it!

Did you search on the number MBD026U? Nothing relating to UK sellers came up on the first couple of Google pages here, only Oz (and a few other random ones) which makes sense if it’s likely for the Australasia market.

I think it’s used in this kit:

lsiauto.com.au/products/mbk-6276

Many thanks, will look into that!