Stuff EFI - I can't use any more power :(
Turbo Mini Forums

Twin-plates... now there's a thought!

Already drawn up by a friend of mine a few years back, but needs one special clutch plate (not good). Also has quite a high inertia as a whole assembly.

They'd likely need more disengagement length, but that is not exactly difficult to sort compared to the rest of the flywheel...

dave surely twin plates in the same size will offer no more friction as it still transferes through one side as as single does .all you are doing as in your own words is making more surface to soak up the wear


carl

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

Dave,

i was always having a slipping problem with mine too.

my setup would only be about 150 to 160hp and a AP organic with a grey cover would start to slip after only 2 - 300 miles old.

i went through so many different types of covers and plates over a 2 year period it was not funny.

in the end i read your post and a few other Marcel Chichak's too and then i sent my assembly away to a mini enginers shop here in sydney and he said no it all looks ok to him so i was very confused.

but then he called me back after haveing a real close look at it and siad its all fixed now come and grab it.

in the end cause i had fitted aother strap at each pint (9 in total) i had to take that same thickness (maybe 30 to 40 thou) of each post and then rechecked it again the the spring was a little flater when all bolted up but he then machined off another 25 thou from the posts and the spring sat just prior to flat.
he said you do not want the spring to be flat cause then it has little pressure ont he plate causing it is balancing of sorts between over flat and prior to flat.

i took some pics of mine all together before i put it back on but i am unsure of how to upload hem.

179hp on 12psi 1293cc of pure A series
14.0et @101 mph

turbodave,

did/have you made any progress with a revamped clutch system?

Here's what ( little ) I know about clutches.

I was always led to believe that a smaller friction area on the plate, will result in higher clamping loads acting on that area, and it will grip more for a given single.
So say an 8 paddle plate will wont grip quite as hard as a 4 paddle, but it the 8 will also engage smoother.
If you look at various cars, you can get 3 paddle, 5, 6, 8 etc. The models with less number usually handle more power.
I'm not quite sure myself if thats true. It sort of makes sense. But ultimate clamping hasnt changed, and there is less friction area, so in a way it doesnt make sense.

Have you considered different friction materials ? The first clutch I bought for my LS1, actually used a full face IRON friction material. I thought this quite odd. I fitted it, and it actually drove almost like a standard clutch !!! I only ran it at about 500-550bhp for a few weeks, then had other issues with it, so swapped for a different clutch, this time 6 paddle, sprung centre scintered bronze. The Iron disk was rated at something like 800lbft, although guys had ran much mnore than that, and launching on slicks. ( as yanks do )
I dont honestly know if Iron is a better friction surface than scintered bronze type materials. Cant really compare the numbers to a Mini, as LS1 clutches are massive ( about 300mm OD ) But the option of using different friction materials is very valid, and should be easy for any clutch specialist to accomodate. Exedy and others are now pushing carbon materials for their friction materials.

Twin plate clutches usually drive pretty good, compared to a comparable single. I had a twin plate organic in my old Rover V8 twin turbo. It drove like a normal clutch, and held about 450-500bhp for a couple of years. That was the only clutch I could get. Nobody made a suitable single plate. But when the twin works so good, why use a single ? ( apart from cost )

Look at all the big power Jap cars. Virtually ALL of them use either twins or triples. Quite often the cover is the same for these. Clamping loads arent usually that high, as there is so much extra friction area. They are usually quite nice to drive with, esp compared to a single disk paddle clutch.

Perhaps if you were to approach Quartermaster, or similar, they would be more helpful in sorting a twin plate ?

Taking the Exedy twin. The twin is rated at about 750bhp and the triple 1200bhp. This uses the same cover, flywheel, and only changes the centre components to all the addition of a 3rd friction disk.

Inertia isnt a concern, as most of the twins are small diamater, usually about 7.25". They would carry a lot less inertia than say a verto assembly, with the flywheel having most of its mass at the outer edge.

Obviously it will be complicated to bolt one to a Mini though.

There used to be some good information on teh exed/daikin clutch website, but cant seem to find it now.
It had good exploded views of their twins and triples.
You can sort of see here on their pdf file about the carbon clutches.
http://www.daikin-clutch.com/products/PDF/...resentation.pdf

Have you tried contacting places like Ram, ?? I know a Mini wouldnt be quite their normal thing, but they do claim that make custom clutches for people.

Edited by stevieturbo on 20th Aug, 2005.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

I dont think a twin palte would affect the synchros that badly. The relatively small plate diameter, and the axtra drag from the idler gears should be enough to slow them down for smooth changes.

I ran my twin plate MCleod for over 2 years on my RV8 TT. The clucth did wear quite a bit during that time, but never once did it slip. Twins really do grip.

But if you can get a single to work, no point in having to consider twins.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Steve, It does affect the synchros... no way around that.

When you make a shift, you're speeding up or slowing down the clutch disc. If you add inertia, you need more time to synchronise fro the same lever load. OR you can add lever load and reduce the synchro time.
The main reason multiplate clutches reduce in diameter, is because increasing friction couples has such a huge effect compared to increasing effectve radius of the friction surfaces.
This, along with the resultant increased inertia from the multi-plates is a reason why the plates are always reduced in diameter.

Again - what you say about wear - borgbeck clutch covers are a lot less tolerant to wear. The mini diaphram is not really suitable for a twin.

Edited by turbodave16v on 22nd Aug, 2005.

oooh!

Chatting with super-clever Graeme a few days ago, I realised I'd overlooked a major detail in the inertia stakes.

The worse-case clutch inertia on a stock tranny is using the A+ gearset and the verto 'sprung' friction plate.

Now, the closer ratio of the SCCR tranny, coupled with the inertia of two organic 'solid' friction plates is - from my initial calcs - not too much more excessive than the Stock A+ setup (wrt the synchos)...

More investigation needed!!!

graeme really is a clever chappy! is there anything he cant do?!

he is a sharp cookie,

Team Racing

And dont forget, most twin disc or race type clutches are available in much smaller diameters, which will reduce inertia a lot over a large diameter disc.

Some race clutches are as small as 5 1/4" although not sure you could ever adapt one that small for Mini usage.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Yeah - I'm trying to use stock plates though Steve.... Don't fancy having to get new plates every time I need to change the clutch :(