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Twin Clutch into an S4S?

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  • 9 months later...

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Well after 9 months I have exhausted all options for an organic twin plate clutch option for the 4 pot engine.   There are always the sintered race spec clutches for those who are just tracking a

Correct .. This particular design flywheel does not have the triggers for the Delco system.  But there is no reason why another design incorporating them could not be made..   What is more releva

Interesting thread this and a problem I had insofar as the standard single plate clutch slipping at high boost. Mostly around the 4th and 5th gear wot point and very frustrating. Power just bled off i

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Have looked into this in detail with AP racing engineer. The problem is getting one to fit.

The room within the bell housing is very restrictive and the set up height for a twin plate

push clutch to tall..  I believe that is why the V8's were pull type. My search is not over

but the costs for such a conversion are not cheap. 

I presume you are thinking a twin plate could give you the torque requirement with less

peddle loading. This would be true but not in the power zone of std or slightly up rated Esprit.

They are primarily designed to take much higher torque loads with the same peddle loading.

So for that reason you would need a special making....Expensive.!!! 

Hope that answers your question..

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Im fitting one of these onto a flywheel at the moment for someone. Although taller overall there is something less you need...ok I dont know Im just doing what Ive been asked to do....ask Andy Clements he seems confident!




"Belief is the enemy of knowing" - Crrow777

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Hi Scott,


I'm really interested in what you are doing.  Ideally I need a twin plate set up to gain

the extra torque needed for my engine..  Unfortunately after exhaustive discussions with

AP racing there was no twin plate clutch suitable for road use that will fit in.. (From AP or Helix)

As it is the set up i have needed massive mods to make it work.. but is limited to 450ft lbs at present.

I would love to know who's clutch you are using, what the setup height and clamp load is plus

any torque figures you have..

This will be an area which will come of great interest to owners who improve their power outputs.

At the moment i am stumped with regard to AP and Helix coming up with anything.. so your input

would be much appreciated..



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Hi Dave,(changes) have you looked at Tilton For a clutch, they are imported from America by Competition Supplies of Silverstone who's service I have always found to be very good. The Tilton Guru there was Bruce Chambers, he set Competition Supplies up I don't know if he is still the man to talk to or if he has someone else there now that covers the Tilton range for him, could be worth a call. There phone number is 01327 857991 and the web site is they have details of the couch range on the website.

Hope they can be of some help

Regards Dan

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When I compared the SE/ S4 type clutch t the AP the height of the fingers seems to be approximately the same when compressed, there is a massive difference in finger height when the clutch is not fully bolted down but that seems to equalise t when torqued down.There is a nagging concern that by the time I take that almost negligible difference and add the different bearing, it may be to much but short of lots of time and ots of guess work before getting the bearing, it seemed the best way wa take the plunge and use one of my flywheels to find out. If it is too much then the next bit is to use a flexiplate (for starter and timing) and a thinner flywheel for mounting the AP clutch cage.

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Hi Andy,


Which twin plate system are you looking at.??   I exhausted the AP / Helix range. 

With the 50mm thrust bearing height and a 6mm ware allowance, there was no room in

the UN1 bell housing. The error was 10-15mm so not even close.. Plus the length of the primary

shaft and splines restricted how much the box can be spaced back.  As it is the system I

have with single plate and 45mm concentric bearing only just fits with a 3mm spacer between

the box and the block.. ( I can only space this due to having longer primary shaft in GTO kit.)

That is also with a special set back flywheel and recessed bell housing..


I have laid out all the obvious options on the drawing board with weeks of research.

So anything that may be close will be of interest to me.  I also need the torque capability details.

It was this that ruled out the twin V8 pull system.  However i may need to see if there is a variant on that

which i can get made, along with bespoke bell housing.. Also go over all the options again looking at

new angles..


Dan thanks for the info on Tilton, I had looked at their catalog range with no joy, but will phone and ask 

about specials..  The Americans do seem more able to accommodate 1 offs better than the UK now.


For those wondering why this is so much of a problem. Its because we are trying to use organic drive

plates with a peddle loading suitable for road use..  not a racing clutch..  

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  • 8 months later...
17 hours ago, sailorbob said:

I'm guessing the new flywheel doesn't work with the Delco ecu crankshaft sensor?

Correct .. This particular design flywheel does not have the triggers for the Delco system.  But there is no reason why another design incorporating them could not be made..  

What is more relevant though is the reason you would go for a twin over the single plate system in the first place.. In most cases it is because of the power output on the 910 engine exceeding the single plate system..  From my research and experience the standard Delco ECU system is not capable of managing the 910 engine at much over 350 bhp and even then with continuity  issues.  As a bolt in single plate system can handle this then a twin system is overkill.. However for those who want a smoother more responsive or tuned 910 then a stand alone ECU is the answer. These will need a different trigger sequence than the awkward Lotus one, so a suitable flywheel or front pulley trigger wheel can be installed..  Saying that M. Kassim has managed to program the original flywheel trigger sequence into his stand alone unit, but it took some doing.

What this and the 412 thread shows is that the 910 engine is a versatile unit that has great potential and now has a road going twin plate clutch option available if required. .         

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  • 2 weeks later...

Interesting thread this and a problem I had insofar as the standard single plate clutch slipping at high boost. Mostly around the 4th and 5th gear wot point and very frustrating. Power just bled off into the spinning clutch.

I was getting a bit despondent about the whole thing and just lived with it but when the car went in for a gearbox upgrade it was suggested that we look at installing a Helix competition unit Geoff had. It had an uprated clamping pressure, from 7000g to 9000g I seem to remember. Anyway, it has completely solved the problem and what's more feels sharper and more direct. Less peddle travel and a slight bit more on/off but I like it very much.

I am not sure what part number it is or even what it cost me as the price was including an LSD and synchros etc but I know it's a fair bit more than a standard one. Esprit Eng did the work and it survived a full day blasting around Silverstone GP last week and I drove there and back. My car is race prepped and will hopefully do another full season this year so I can keep you informed how it performs if you want.



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