Currently in the midst of an EFR 6258 project. Assuming the result will be in the ~300tq range at the wheels. I was very attracted to the ACT HD/Race 6 puck combo for its characteristics, but I can't seem to find any empirical data on when it begins to slip. It's rated for ~300tq but I'm assuming at the crank. My next option was the FM stage 2 since it's proven at that power level and seems to have good characteristics as well. I was about to make the purchase when I saw a post of someone running 300tq on a competition clutch stage 4, and noting the exact characteristics I was looking for.

Does anyone have any experience with the competition clutch stage 4 or know more about it? Any empirical info on the ACT or FM wouldn't hurt either. Running a 12lb flywheel and 6spd fyi

 

I had the Stage 4 Comp Clutch and it sucked to drive around. Chattered all the time.

FM2 happy meal is a great clutch for a daily driver. Was comfortable with 351whp/349wtq. It started slipping at 402wtq.

Anything in the 400hp region, I'd jump straight to the SuperMiata Twin Disk, it's actually quite driveable. Way better than the Comp Clutch Stg4. I'd never buy that clutch ever again. Ever.


Ironically, the SuperMiata and Flyin' Miata kits are built by competition clutch. Go with one of the vendors.

 

Thanks psyber. Hadn't seen any real reviews of the stage 4 so exactly what I was looking for. Surprised chatter was a real issue since it it looked like they tried to emphasize springs on that one.

Thinking FM2 is the way to go unless anyone has experience with 300+ on the ACT HD. The XT sounded like it had a bit too heavy of a pedal feel for my liking as the car will be street driven often. Previous clutch was an FM1 and something a bit more agressive would be preferable. Kind of left field but I suppose a clutch masters FX400 is an option as well.

 

I think the spring made it worse. It will hit this harmonic where it'll buck depending on how hot the disk got. Maybe I'm just a pansy. Again, twin disk and FM clutch felt way better.

Several folks here run the ACT stuff with great success.

 

Well I'll definitely cancel the the stage 4 as an option then.

I think I may have been misinformed about the ACT though. I now believe the ~300ft/lb combo was for the HD pressure plate with a street performance disk. I saw another user throw out a ~350ft/lb figure for the HD/race disk combo which is perfect for me, however I'm not sure where that figure is from. ACT just rates the combo at 74% over OE, whatever that means. I'm waiting on an email response from ACT but I'll post the response here in case anyone else needs this thread in the future.

 

XTSS was great and was stronger than the 6 speed.

I'm using a BMW transmission now.

 

Let me know if I'm wrong but general consensus seems to be that the XTSS combo isnt very streetable with the heavy pedal pressure

 

I'm with psyber on that one. Had the cc4, it was a nightmare in daily traffic. Unable to modulate and very chattery. Switched to the FM2 and have been happy ever since. EFR 6758 at 320 whp/400 Nm wtq

 

Have the CC stage 4 in my car and it really is a bit chattery. Needs a lot of throttle and quick take offs to be somewhat smooth. I drive it until my 5 speed breaks, did some pulls with 240 wtq and it didn't slip a bit

 

My 110lb wife could drive it without complaining but she's a gymnast. Maybe it would be too much for you, lol.

 

Clearly I misread lol. Definitely sounds like there's better clutches for the power than the CC4 though, so best options seem to be:

6-puck - ACT HD/Race (ZM2-HDG6) conservatively rated for 310ft/lbs

full-face organic - FM stage 2 conservatively rated for 353ft/lbs

Ill be going with the HD/Race since it's conservatively rated right at my power goal, and I prefer the 6-puck design. Thanks all for verifying my stream of consciousness lol

 

I fail to understand why anyone would go for a weaker 6puck clutch if there is a better solution that works like a regular clutch in daily traffic. Do you like to give yourself a nice spanking from time to time, too?

 

Because racecor street credz man...

But seriously, I understand the FM2 is a more streetable option, but I like the challenge of driving a 6-puck. I enjoy having my project car being a more raw driving experience than my daily. This ACT combo isnt an on/off switch though so I don't see it becoming a headache. I'll swap to an FM2 if I'm too much of a ***** for it.

 

Then put your purse away and buy the Comp Clutch stage 4 if you want to be challenged.

 

Challenge > Challenge + headache. Obviously I'm looking for some level of streetability, just not the level of a daily driver.

 

After sleeping on it and reading a few more dyno charts, I'm kinda relegated to the fact that the ACT HD/Race is just gonna cause issues down the road when I want ALLOFIT.
Maybe there is some merit in the collective agreement of multiple Miata vets with vastly greater experience than myself...

FM2 it is lol