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What is the strongest clutch you can buy

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I am curious what is the strongest (highest torque spec) clutch you can buy for an Esprit. I have heard people claim that the S4s clutch is all you ever need, but you have to change the flywheel. How does the S4s clutch compare to the +35% torque clutch kits I see from PUK and Ramspott & Brandt?

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Hi, forget +35% what you are looking for is figures what the original is to what is claimed as uprated find out what the clamping force the pressure plate

produces and then you have the answer.

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Clamping force isn't all of the storey though, just as important (if not more) is the friction material and it's coefficient of friction.

It's the same as brakes, 2 callipers can apply the same clamping force but the one with the better pads will give more braking force, so you need a good strong clutch clamping force and a pressure plate with a good material surfce. Not to mention flywheel and other components must be in good condition.

I guess the "best" clutch wouold be the twin plate, like the later V8s, but it's a matter of how far you're prepared to go to achieve that ( the flywheel, bell housing and slave cylinder on a V8 are different to the standard single plate clutch).

Andy

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Hi Graham,

IMHO you should stay away from the S4S clutch. First it is very expensive, second you have to change the flywheel or at least you have to drill new holes and threads, third the S4S clutch is very heavy and unpleasant to operate, fourth the S4S clutch is known for not holding up too well ... IMHO the original S4S clutch is not a very good one, indeed.

Cheers

Marcus

I am curious what is the strongest (highest torque spec) clutch you can buy for an Esprit. I have heard people claim that the S4s clutch is all you ever need, but you have to change the flywheel. How does the S4s clutch compare to the +35% torque clutch kits I see from PUK and Ramspott & Brandt?
Edited by Paula&Marcus

Marcus

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Thanks for all the quick responses! So I guess the best bolt on option is the upgraded "+35%" clutch kits?

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Good point Mark, I will look into this too as there is a local shop that does this for racing SCCA guys here locally.

Artie


89 White Esprit SE

...a few little upgrades....

93 RX7.....Silverstone

....slightly modded...Muahaha...

New Addition:

1990 300ZX TT......Hmmm

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This may be out of turn but, by all accounts the gearbox is the Achilles heal of the Esprit, the stronger the clutch, logically the more torque through the box. Clutch much cheaper than gearbox.

I went through this once, tuned engine, disitergrated clutch, tougher clutch, blown gearbox, tougher gearbox, broken diff, drive shaft next, then sold the car!

Breaking cheap bits is best, Roger


Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

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This may be out of turn but, by all accounts the gearbox is the Achilles heal of the Esprit

Often noted, rarely proven if you ask me!

Your logic is sound though! :)


88 Esprit NA, 89 Esprit Turbo SE, Evora, Evora S, Evora IPS, Evora S IPS, Evora S IPS SR, Evora 400, Elise S1, Elise S1 111s, Evora GT410 Sport

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My biggest problem now is my clutch is slipping big time when I get on the power since I have upgraded my engine a bit. I have adjusted the slave cylinder such that there is no preload on the clutch at all and its still slipping. I hear (perhaps Artie can chime in here) from the garage that worked on the car before I got it that it has an upgraded clutch in it. I just purchased a +35% clutch from Marcus and I really hope that doesn't slip because if so I will have to get a custom one made which is going to cost $$$$$.

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I once thought my clutch was slipping, then I realized it was my tires... :)


Visit Sanj's Lotus Esprit Turbo SE pages

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I once thought my clutch was slipping, then I realized it was my tires... ^_^

Ha! That same thing happened to an '03 V8 owner here. I had to tell him it was the open diff allowing one wheel to spin.


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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At first I figured it was wheel slip since I still have an open dif, but then I was pulling onto the highway and gave it the beans from about 40 mph to about 80mph and the clutch was slipping like crazy :-( I actually haven't had a problem with tires breaking loose (other then in wet conditions) yet. I am running Yokohama ADVAN Neova AD07 tires mounted on V8 rims and they are fantastic!

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Um...

Clutch slipping like crazy often results in FIRE in the Esprit!

Stop driving!

I know of several who have asked about clutch slipping, and were told not to drive, and then later posted if anyone wanted parts from their burned car.


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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Bad news....I pulled off the gear box and found out that my car was equipped with an S4s clutch from the PO ^_^ This means that even with the upgraded S4s clutch, she still couldn't handle the power. When I had the engine out of the car initially I inspected the clutch/flywheel and it looked like it was in like new condition so I didn't think anything of it. I had no idea that it was an S4s clutch at the time. I know it is an S4s clutch now because I just got a +35% (SE) clutch in from Marcus and found out that the bolt pattern for the new pressure plate dose not match the one on my car. Also I had heard from the garage that worked on this car before I picked it up from an insurance auction that they "thought" they had installed a "lighter" flywheel with an upgraded clutch. So now I have a bit of a problem. Should I go through the hassle of buying an SE flywheel so I can fit up the +35% clutch from Marcus or should I go have have a custom high output clutch made over here in the states? What do you guys think?

Cheers,

Graham

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Was there anything on the clutch or flywheel that might have made it slip? Oil, grease?

Is the lip from the friction surface to where the pressure plate correct. If this lip is not the correct height it can reduce clamping pressure of the pressure plate.


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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Lottie is allegedly running 370+ (at the crank) and her clutch doesn't slip. I didn't do the work, but I'm fairly sure it's the standard SE setup. Only thing the interim owner said was that he thought he'd gone for too thin a braided hose, which was making for a slower pedal - but I haven't noticed it.


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"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming: "Wow, what a ride!!"

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Should I go through the hassle of buying an SE flywheel so I can fit up the +35% clutch from Marcus or should I go have have a custom high output clutch made over here in the states?

Why not have the S4S flywheel bolt patern altered? I know the metal is very hard, but it should be possible to drill and tap if done with suitable tools.

Andy

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I am not entirely sure what you mean Travis concerning the pressure plate lip however, there was no sign of grease or oil on the clutch when I removed it. I should also mention that when I stripped the engine and reinstalled the clutch many months ago I put on latex gloves and used a oil/grease solvent on the clutch setup to ensure it would be clean.

As for crank HP, although I have not dynoed it yet, this car should be putting out more then 400 bhp :-P

Finally, I am considering having the flywheel machined to accept the standard SE setup, but I am also going to check how much a custom clutch cost.

Does anyone know what car the S4s clutch came from? I pulled off the pressure plate and clutch which both say Valeo on it, but of course they don't have anything stating they supplied a clutch to the S4s...So if anyone knows what car they stole the S4s clutch from it would be a HUGE help!

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The flywheel has the friction surface where the clutch engages, and then there is the ring where the pressure plate bolts down. The height difference between the two is critical to the clamping pressure of the pressure plate spings.

Let's say for instance the flywheel was machined, and only the friction surface is machined down, then the distance would be shorter and the clamping force reduced.

WHen machining these Esprit flywheels, the friction surface and the ring around that where the pressure plate mounts should BOTH be machined and the proper step height shoulld be maintained.

BTW, never have a flywheel (or brake rotors) machined on a lathe with a cutting tool. It will reduce the friction properties and the life of the flywheel.

Always have them Blanchard ground, this will provide a better more consistent friction surface with better wear.


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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Thanks Travis! Do you happen to know what the proper step height is for the S4s flywheel? It appears I am going to have to get the flywheel ground and I want to make sure it is 100% within spec.

I spoke to Jeff at JAE and he firmly believes the S4s clutch should be able to withstand the amount of power I am producing. The reason for why mine was slipped is possibly becuase the flywheel was machined improperly by the PO or maybe I had not torqued the pressure plate down enough. The plan now is to fit up the standard S4s flywheel with a new S4s pressure plate and clutch.

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