Clutch choices for 350-400HP !!
 

What's the best clutch choice for Track Miata with 350-400HP and 6 speed transmission. The car has built 1.8 and EFR6758. Any input is appreciated.

How much torque? Will you street drive? Does your trailer have a winch?

The car is still registered so don't mind taking it out for some fun driving. Yes My trailer does have a winch but even my other race car with more power is not that crazy and I'm still able to drive it up. I'm not sure about the torque since haven't finished the setup so it's not running yet. The car is going to be 85% track duty.

The 949 twin disk would be the no compromise racing clutch. Easily able to take what you're dishing out and its the lightest setup going, but I wouldnt want to get stuck in traffic with it or drive the car onto the trailer with one. The more street mannered option that adds a couple pounds would be the speedsport, its rated to 300ftlbs but goodwin claims to be running 350ftlbs though it on their shop car. Super easy to drive, engages so nice, very easy to launch. Or there's the normal choices everyone else makes that arent as light as the 949 or speedsport and arent as easy to drive as the speed sport but are cheaper and more common.

Why not? I have the organic twin-disc and it is was okay on the street and just fine getting onto the trailer. Have you driven one? Maybe the ceramic is not as nice, I haven't driven one of those.

robert

I've got the FM2 currently and if drives beautifully in traffic...only slightly stiffer then the factory MSM clutch.

Would probably do the trick well for your torque levels...I'd upgrade to the twin disk if ever given the option though...and the monies.

I drove an organic twin disk. Wasn't easy to negotiate the paddock, wasnt easy to modulate on the launch. Its on a N/A auto-x car, owner seems to be on a once a year replacement cycle for the discs with most of the wear coming from driving the car onto the trailer. The ceramic would really be required for the OPs car.

Well, that is certainly not my experience. I've had mine in place since 6/2011, about 95 days on track and haven't had to replace the discs. Clearly I am doing it wrong.

Mine is a stock motor with I/H/E, ie low power. Maybe that makes the difference.

robert

I haven't driven my twin disk too much. Coming from a horribly slipping and pedal that requires 0 effort to push in to the twin disk I usually don't have trouble driving it. It seems that once I start driving it more I should be able to drive it pretty easily.

I wouldn't buy anything but twin-disk.
- less load on tranny
- faster shifting
- less inertia

Drove a 949 twin disk on the street
Would never buy one for a street car
Would absolutely buy one for a race car tho
Just my .02

twin organics with stiffer spring would be a streetable option for 400 hp...

I have one of each. I could DD the twin organic smoothly without a problem. The ceramic is a little harder, but I can still pull a car onto a trailer with it. I really doubt pulling the car onto a trailer wears the discs significantly.

I would love to go to the 949 twin. I have driven cars with them and I would not have an issue even daily driving them actually slightly smoother than what I’m using now.

Currently though I am and have been running a 1.6l Fadanza 7 lb flywheel with a 1.6l ACT extreme pressure plate and an un-sprung 4 Puck Disk. The setup is several pounds lighter with a much lower inertia than a 1.8l setup. I can drive it just fine on the street but it is certainly not OEM smooth like. I can launch it Ok as I have won some National event Pro Solos with it. It is about as light as you can go short of the twin. It has held up fine and holds somewhere well over 300ft-lbs of rear wheel torque. The sprung centers tend to blow apart on me though and since they tend to bottom out hard at these power levels in there range of isolation I don’t think they actually are any easier on transmissions than the un-sprung.

From My experience ACT seems to be conservative on their torque ratings I’ve gon way over on a few of their clutches and they have held. Some other clutch suppliers I have found not to be conservative. Spec pretty much fails right at the rated torque.

Thanks for all the inputs. Actually 949 twin ceramic disks and OS Ginken Ts2bs twin disks were my two choices since they are in same price range for me. Has any one used OS twins ?? Any thoughts on it ??

I'm running a Competition Clutch Stage 4 (sprung ceramic 6 puck) on a built 1.8 with EFR 6258 and 6 speed. Just from breaking the motor in, it felt fine driving around. Clutch pressure is surprisingly light.

Almost stalled once but I think that's more because of the light weight fly wheel. Never did any hard pulls since I need to track down an oil leak and finish breaking in/tune

I cant find any spec data on the OS like what is the weight or rated torque capacity.

949 twin is like 14 lbs in organic twin

My 1.6l setup with ACT Ive been using for years is only a little over 15 lbs and cheap by comparison works suprisingly well for the application.

I would bet the OS Giken is heavy by comparison.

How is your setup so light? It should be closer to like 16-18 depending on how much lighter than 4 puck friction disk is than the stocker. 7 pounds for the flywheel 8-9 pounds for the pressure plate 1.5-3 pounds for the friction disk. The weight advantage the speed sport has is that a good chunk of the pressure plate is aluminum since the friction surface is carbon fiber rather than steel.

FW = 7.3 lbs
pp = 7.2 lbs
solid disk = 1.5 lbs.

all the 1.8l stuff seems to end up over 20 lbs total. 1.8l pp is over 9 lbs I beleve.

Racing Multi-Plate | OS Racing Clutch | Products | OS GIKEN

Looks like the lightest OS twin is advertised at 19.4 lbs. for clutch and flywheel. There single plate is 22.5 lbs. They give no torque ratings. difference between billet aluminum or pressed steel pressure plate is only 0.33 lbs on the single.

Seems pretty easy to get that weight with a clutch that has a known acceptable torque capacity and drivability for half the cost or less.

I’d take my 16l Fadanza, ACT Extreme puck disk over that.

Anyone else care to share their experiences with FM2 clutch? I think I am about to order one for my street car daily driver. Need lots of torks capacities......The FM2 seems to be rated highest and I don't want an on/off switch.

I have the race version of the speedster clutch. My car is na so I'm nowhere near the power limit. It is an easy clutch the modulate and very street friendly. It has a light pedal and so far has held up to many launches at autocross events. There is a bit of chatter on over-run, but that's the only clue that it's anything besides stock.

I like the fm2 just fine for the street. I'm probably only making 250-275whp though.

It comes with a really nice HD throwout bearing too.

I'm on FM2 on a street/track car. And it's fine. It's much heavier than the stock 1.6 one but even in heavy traffic I'm OK with it.
I have the organic and it's very easy to modulate. You only remember it's not the stock one when stopped in a red light and you remain with your food on the clutch pedal, or driving very very slow in traffic.
I tested a FM1 from a friend of mine and it's like stock or even lighter and will work fine on most non build motors, I only bought the FM2 because I was afraid that the FM1 could fail in track. I only have 220 ft lbf, I hope I have clutch for many years.

The OSG twin currently offered is a spec we developed with them about 5 years ago. 21lbs actual. Thats as light as they were able to get it so we gave up and went elsewhere. Beautiful piece.

Trailer loading and street driving doesnt wear our organic twin. Full power autocross launches, particularly Pro Solo launches on 275 Hoosiers does.

Ceramic twin is driveable on the street but its not fun. Its a race clutch in function, not just name.

Can you give feel comparison between the 949 twin ceramic and an ACT extreme 1.6l unspung 4 puck on a Fidanza flywheel like I currently drive on the street and do pro-solo launches with?

I think Crusher had the organic twin in it when I drove it. It was definitely smoother than my current race clutch setup that I have very little issue street driving.

Worst thing to kill my street drivability by far is the AWR engine mounts on my car.

Probably about the same but I'm guessing as I have not driven a car with your precise setup. Similar setups yes. My vague recollection of a 1.8 organic ACT Extreme I drove was about a 65lb pedal with a distinct over center cam feeling and engagement at the floor. The Race twin has more linear feel and can be adjusted to engage at the floor or higher to the drivers liking.

That is kind of what I was thinking. the 1.8l act extreme with an organic disk is really hardly any different feeling than my 1.6l 4puck other than the rotating assembly having a much lower inertia. Modulation is fine I have no issue with pedal effort and I've gotten use to the engagement point close to the floor. the biggest thing is having a slight range of movement where you can smoothly slip it some.

Worst clutch I tried was the spec stage 3+. Soft pedal but on off chattery engagement and didn't hold advertised torque level.

Rover had an ACT XT, 6-puck, and Fidanza flywheel when I bought it as a turbo car in 2009. Can't remember whether it was 1.6 or 1.8 parts. I thought it was undriveable on the street, worse than my ceramic twin.

The race twin is about a 40-45 lb pedal. Noticeably lighter than an ACT extreme

I wonder if the 1.6 is much easyer than the 1.8 XT with pucks. I dont have much issue at all with a 1.6l 4 puck XT. I have a stock pp with a 3 puck unsprun disk in my 1.6l spec miata and it is quite a bit more grabby of launch than the ACT 4 puck in my beast.

That's really curious to me, as well. My two cars have the XTSS and the organic 949 twin. The former is hugely easier to drive than the latter (7 lb fidanza 1.6 flywheel), but only rated to 305 ft lbs.

I've yet to feel a pucked anything that wasn't a nightmare to drive, if there's such a beast out there, I'm interested given there's no more organic 949 twin.

I did lots of miles (20k+) with a 1.8L ACT HD, sprung 6-puck, and an OEM flywheel. Totally doable on the street. Grabby, yes, but totally manageable. The difference was the flywheel, I suspect. Once you drop under 10lbs with the flywheel, pucked clutches just aren't truly streetable.

Im using the ZM1-XTR4 on a 7 lb 1.6l Fadanza flywheel. it has been pretty bullet proof and I do not find it that hard to drive in traffic or launch at all. Daily comute in urban traffic jams maybe not so much but its kind of pointless using a car like this for that purpose. It's rated at 350 ft-lbs. but I think ACT is conservatve on rating. My ZM2-HDSS held more torque than its rating of 224 ft-lbs for sure. It was not that big of change in feel between those two. I must admit the 949 twin Organic felt smoother but if the twin ceramic feels like my current clutch I wouldnt have a problem with it either.

I gave up on sprung centers in the smaller diameter 1.6 size they can't handle the torque abuse and the rivits holding the center together start to fail and come apart so you have to live with the unsprung center clutch rattle and buzz if you want the preformance of light weight and small diameter for low MOI.

You said the 949 organic twin was DD able without a problem. You likely have a lot more skill than I, given I still accidently do burnouts when trying to go from a start. Just pointing out that the person's skill level might have a lot to do with what's streetable, as the organic is barely, barely, not quite but kind of streetable for me.

I did repeated driver swap practice and launches and crawling stop and go laps around a crowded paddock area in Crusher with a 949 twin in with people all around. It felt very easy to me.

Maybe it is some experience level. I think I drove only manual cars for the first 5 years I was driving before I ever sat behind the wheel of an automatic. I’d probably be really good at riding a tall Unicycle if I put that much time in it I guess.

Try the "heel plant" technique if you haven't already. That is planting your heel on the floor and modulating with your ankle instead of raising your entire leg. Makes it easier to control the heavier spring and keep from lurching

Rover started out with an ACT HDSS/Fidanza combo when it was originally built as a VVT-swapped car. When I swapped it for an organic twin last year, I did not tell my father, who drives the car at 8-10 HPDE events every year. He did not stall it the first time, and did not comment on the clutch until I asked him about it. To me, that's the hallmark of a streetable clutch (don't tell someone what's in it and see if they stall it).

The XT 6-puck that came in Rover when I purchased it as a 1.6 turbo car was so comically bad, we used to let anyone try it out and bet them money they would stall it the first time. I never had to pay out.

All this talk about the 949 twin organic makes me wish I had one. Maybe one day in the future it will magically come back to the market... ;)