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-   Suspension, Brakes, Drivetrain (https://www.miataturbo.net/suspension-brakes-drivetrain-49/)
-   -   Clutch choices for 350-400HP !! (https://www.miataturbo.net/suspension-brakes-drivetrain-49/clutch-choices-350-400hp-78495/)

Amellrotts 07-13-2014 04:49 AM

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.

6speed 07-13-2014 01:25 PM

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.

flounder 07-13-2014 02:18 PM

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.

DJ_Sixty 07-17-2014 05:30 AM

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.

emilio700 07-20-2014 02:06 PM

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.

bbundy 07-21-2014 07:44 PM


Originally Posted by emilio700 (Post 1149693)
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.

emilio700 07-21-2014 08:30 PM


Originally Posted by bbundy (Post 1150057)
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.

bbundy 07-21-2014 09:56 PM


Originally Posted by emilio700 (Post 1150066)
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.

Savington 07-22-2014 01:45 AM

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.

emilio700 07-22-2014 02:11 AM

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

bbundy 07-22-2014 06:02 PM


Originally Posted by Savington (Post 1150120)
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.

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.

Nagase 07-23-2014 04:56 AM


Originally Posted by bbundy (Post 1150358)
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.

Savington 07-23-2014 12:37 PM

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.

bbundy 07-23-2014 12:58 PM


Originally Posted by Nagase (Post 1150463)
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.

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.

Nagase 07-23-2014 01:00 PM


Originally Posted by Savington (Post 1150610)
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.

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.

bbundy 07-23-2014 01:18 PM


Originally Posted by Nagase (Post 1150620)
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.

emilio700 07-23-2014 02:06 PM


Originally Posted by Nagase (Post 1150620)
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.

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

Savington 07-23-2014 02:32 PM


Originally Posted by Nagase (Post 1150620)
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.

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.

Dustin1824 07-23-2014 03:42 PM

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... ;)


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