New Kevlar clutch

Hi all. Just an FYI on something I'm working on that might interest you:

My Coupe has a rather unique issue; it has one of the highest torque outputs of all road-legal Coupes (over 400 lbsft), but it is probably the only one that is driven daily!

My Coupe's torque output is way beyond any organic clutch, including the Helix item. So up until now I've had to use paddle clutches. I used to use CG Motorsport items, but I sacked them off after I had to take the company to court for trying to palm off two shoddily built clutches on me in a row - and good riddance too: I started making my own custom paddle clutch setups with much better results than any of the trash peddled by CG Motorsport. However, paddle clutches are still a nightmare in London traffic!

So the search for a more traffic-friendly clutch that could handle big torque led me to this bad boy. Custom-made to my own specification:


Got to fit and test it first, but if it works it will be the first ever Kevlar clutch rated to 400+ lbsft (approx. 500 bhp for 20VTs & 440 bhp for 16VTs)

The Coupe might be getting long in the tooth now, but there's no reason why it can't still have nice new things!

Don't you have issues with the stock pressure plate with this high torque output?

Not with the paddle clutches; the cerametallic paddle material has enough grip by itself, but it also eats flywheels - and flywheels are becoming very hard to come by these days!

This Kevlar clutch has an uprated pressure plate though, for more clamping pressure, because Kevlar isn't as aggressive as paddle material.

How much would one if these cost out of curiosity?

Around £480 for the whole clutch kit (uprated pressure plate, kevlar friction disc and new thrust bearing). Much less than a Helix anyway!

A little update on the kevlar clutch: I fitted it last weekend, along with a freshly ground flywheel - my old homebrew paddle clutch didn't tear up the flywheel like previous CG Motorsport clutches, but it still needed grinding.

Straight out of the box, the kevlar clutch felt great - no judder and a nice low biting point. I expected the clutch to have a heavy pedal, like typical uprated organic clutch, but the pedal felt almost standard. The nicest immediate feel I've experienced out of any make of Coupe clutch I've experienced yet.

I've only put 160 miles on it so far. Kevlar requires around 300-400 miles to bed-in so I'll have to wait a couple more weeks or so to unleash the full 400 lbft on it

I can't wait to see how it gets on at 400lbs/ft!

£700+ odd for a Helix is simply ridiculous now so a cheaper, better alternative would be very welcome!

can't you just go for a nice 400 mile drive this weekend then unleash on it and let us know how it went on monday?
It seems my clutch is slipping on high boost.

lol, funnily enough you might actually get your wish! Already done 235 miles and I've got a couple hundred more planned this weekend!

Eager to hear about the new clutch kj, also at what power setting have you found a fresh ish standard clutch start to slip a bit.

Well, I hit the 390 mile mark today so I've started giving it some full load - and holds the clutch holds it perfectly. My Coupe is dyno proven to make 400 lbft and the power also hits very aggressively - far more aggressively than a 20VT with similar torque. If I'm not mistaken, 400 lbft is also more torque than any other 16VT in the UK too. So if the clutch works on mine, it will definitely work with any 20VT over 500 bhp and literally any 16VT to date!




A standard Valeo clutch is officially rated to 270 lbft and I've personally found that a new, freshly bedded one will slip at 280 lbft. But once it's slipped once and overheated, it will end off holding less torque than even the max rating.

That's a VERY good price for a kevlar / carbon clutch.

I paid three times that for a twin plate carbon one after getting fed up with paddles offering crap driveability, and lasting a few minutes.

Is 400lb torque the max limit on this? Anyway of making it handle more?

Been testing the limits of the clutch over the last few days.

I wound boost up to 1.8 bar which equates to around 435 lbft in my car. I found that the clutch holds just fine in 4th, but slipped in 3rd when it hit maximum warp at 4500 rpm.

My Coupe produces a huge amount of midrange torque - much more than any 20VT I'm aware of. Also, more than some 16VTs. Hence mine accelerates very aggressively at full boost (front end goes light, torque steer, brown pants, etc). So evidently the 3rd acceleration was a bit too aggressive for this clutch. But in 4th the clutch grips just fine.

So, I'd say for 20VTs, with their lower midrange torque and smoother acceleration, this clutch will handle 400-430lbft (well over 500 bhp) no problem at all.

For 16VTs I'd say 400 lbft (around 430 bhp) is the very limit.

Even so, there may be more performance to be had: The clutch pedal is quite light - lighter than a Helix organic clutch. So I reckon it may be possible to use a bit higher clamping force.

I'll speak to the manufacturer and see if it's possible to increase the clamping force enough to handle very aggressive acceleration.

This is great info Kj

Sounds great.

Good to hear some developement.

I was scared to try this yellow kevlar friction material few years ago. Been told that is designed for wet clutches.

From picture seems cover still uses factory spring. We measured several fiat pull clutch covers, and there is three "strenght" types. And till today i found only one clutch manufacturer, from italy, which uses cover with different spring. But it has just 10-15% more claping force(over best OEM) and manufacturing is cheap compare to price it cost.
Helix from picture uses OEM spring. But also is rated very safe.

Latest update: I've put a further 100-odd miles on the clock and the clutch now holds absolutely rock-solid at 1.6 bar (about 400 lbft). I'm very pleased with this; definitely the nicest feeling Coupe clutch I've ever used. These kevlar clutches sit nicely in between organic clutches for stock/mildly modded road cars and paddle clutches for full-on track/race cars.



It's fine for dry clutches too. Kevlar is fairly commonly used in other modified makes of car, but as usual we Fiat lot are lagging behind on technology!

I've been told that Kevlar can glaze over if subjected to a lot of stop-start traffic, which can make it slip a bit until you give it some hard driving to remove the glaze again. I live in London, which is entirely stop-start traffic! but I haven't found this to be a problem; I've been able to give it full power straight after being stuck in long traffic jams.

This clutch uses oem springs too, with the pivot point modified to increase clamping force. I spoke to my manufacturer last week. I have a memory like a sieve, but I'm sure they said 10%. Anyway, they said that they can increase the pressure a bit further, no problem. So that's good to know if you have a real beast of a Coupe

What is the clamping pressure of the OEM and other pressure plates?

If not wrong Kj sayed about 270 Nm

Great to hear about this new info Kj

No problem. Glad you find the info useful - and glad to be able to offer the Coupe fraternity a new much-needed product

The torque rating of the stock Valeo clutch is 274 lbft (371 Nm).

The clamping force on the other hand, I'm sure my manufacturer said he measured it at something like 1000 psi

Okay so nearly a month since my last post and the clutch is well and truly bedded in. It now grips in all gears without even a hint of slipping. Yet it's still as well-mannered as any organic clutch in London's finest traffic jams. Suffice to say I won't be using paddle clutches on any of my road cars ever again

My manufacturer has to order in the kevlar clutch material specially from the States. He got the material for my clutch along with his regular order of other parts, which meant I had to time my order with his. However, he says he can make a special order if he can build a batch of at least five clutches.

So I'm thinking of doing a Group-Buy on the forum. Special FCCUK-only price of £480 + postage. I haven't finalised a regular price yet, but it will be around £550.

Post a comment on this thread if you're interested. If there's enough interest I'll set this up

If you fancy another guinea pig, I might be up for it. My last Helix clutch has juddered badly since it was fitted, despite swapping flywheels. The clutch action is also getting too heavy for my ageing legs....

It needs to handle up to 400 lb-ft and about 480bhp - do you think it's up to it?

Edit - just re-read the OP - seems it will cope - kj, can you please give me an honest appraisal of how the new clutch performs in relation to the Helix organic?

Yep I'd say it will definitely cope with your 400 lbft Coupe, no problem. 20VTs don't come on half as violently as 16VTs! Try it, I think it will solve all your clutch/aged leg interaction problems

Absolutely honestly, I like it more than the Helix. Helix are nice, well-made clutches but fairly typical of uprated organic clutches; quite heavy pedal (though not the worst I've experienced by a long shot!).
Often they have a bit of judder. Not half as bad as a paddle clutch, but still can be a bit annoying in traffic.
It also has that same feeling I always disliked about Coupe clutches, in that it feels like the clutch fully opens in the first third of pedal movement and for the other two-thirds you're just wasting leg movement!

My Kevlar clutch, on the other hand, has none of that. Absolutely zero judder - ever. Also, the bite is much lower. Not too low, but I'll bet the first time you pull away you'll bog down because the clutch has engaged before you've revved up the engine enough!

The pedal on my kevlar is only slightly heavier than standard. In fact, when I first tried it I was worried that it wasn't going to provide enough clamping force for my engine. But that has since proven itself not to be a problem.

This sounds like a great option for my Dads Plus. His clutch is fine for now but not sure when it will give up, once it does this will be the first port of call, sounds very good.

This sounds really positive kj.

I am planning a project in the new year and would like to register my interest please. I would also like to know if the manufacturer could confirm what torque the clutch could handle with the updated springs you mention, and what the likely compromises in terms of operation / drivability would be.

Cheers

Great question. Also look forward to hearing the answer.....

NP. I'll speak with the manufacturer and see what they say.

Okay so I spoke to the manufacturer. He said that he could increase the cover plate clamping force an extra 5% or so, but he wouldn't want to go beyond that as the pedal would become too heavy. I'm inclined to agree too. We know that the clutch can handle 400 lbft easily in my own Coupe, which I estimate would equate to around 420-430 lbft in a 20VT - and with a pedal barely heavier than standard. I reckon that 430 lbft covers 99% percent of the 20VTs in existance!

So if anyone absolutely needs more than that, we can go slightly higher with the clamping pressure; I'd make a conservative estimate of around 440 lbft (20VT), 410 lbft (16VT)

I should get my replacement gearbox this weekend - car will be booked in at Motormech over the Christmas period

What is the lead-time on one of these clutches and how much discount do "early adopters" get?

Sounds spot on.

Hi Nigel. About 2-3 weeks. Manufacturing the clutch doesn't take too long, mainly depepnds on how long it takes to get the clutch material in from the states.
_______________________________________________________

What, you want a discount on top of the discount? IIRC you things like clutch repairs? If you reckon you'll require more in the future, I'm sure we can work something out


I'll do a proper thread in the Group Buy section shortly. Let's get this started!

Right, the Group Buy is up CLICK!