Educate Me on Clutches and Flywheels
Interesting angle on the flywheel. Besides noise, are there any other reasons you don't like lightweight flywheels? I have heard if you go too light, drivability can be severely effected. The time investment is most of the reason I am still panning to get a high quality clutch at the moment. By SPM, you mean Super Miata? (I haven't seen that acronym before)
I've had a 9.5 pound aluminum flywheel on my Miata (the Fidanza that FM used to rebrand) for 17 years now and never regretted it. I wouldn't buy a cheap no-name ebay one, though.
--Ian
I've seen stripped out threads on an eBay aluminum flywheel that was properly torqued, so I would avoid one. I used a ~9lbs aluminum flywheel with SuperMiata sport clutch (1.8) for years without issue. I swapped to a FM 10.3 steel flywheel (wanted the ltw one for a track car) and I barely noticed a difference. A good budget clutch for naturally aspirated build is an Exedy OE replacement with an upgraded disc. I've used an Exedy PP and ACT 4 puck disc for a track clutch with no problems for years.
I did the FM1 with their 13lb flywheel. It's about perfect on a 1.6 street car. I get a lot of rattles on decel though, but I think the input for my transmission is going. It sounds like I still have a supercharger installed....
The 13lb free revs quicker and drops quicker, but not so much you can't granny it. Having driven a ton of stock miatas, and several 10lb flywheel ones, I think the 13 is about perfect.
The 13lb free revs quicker and drops quicker, but not so much you can't granny it. Having driven a ton of stock miatas, and several 10lb flywheel ones, I think the 13 is about perfect.
Well after seeing those videos, I think I will skip the cheap flywheels and probably just stay stock. As for clutch though, I am leaning towards the FM1 because of the price and torque rating.
On the note of torque rating, I would like to have someone double check my logic here. From what I understand stock Miata rods exit the engine around 250 ft/lb wheel torque, and general Miata drivetrain loss is about 15%. If I want a clutch that will handle the max possible output of a stock Miata engine, then I should be looking for a clutch rated for at least: 250 *1.15 = 287.5 ft/lb.
Here is my comparison chart:
On the note of torque rating, I would like to have someone double check my logic here. From what I understand stock Miata rods exit the engine around 250 ft/lb wheel torque, and general Miata drivetrain loss is about 15%. If I want a clutch that will handle the max possible output of a stock Miata engine, then I should be looking for a clutch rated for at least: 250 *1.15 = 287.5 ft/lb.
Here is my comparison chart:
- ACT ZM2-HDSS: 245 ft/lb $397
- ACT ZM2-XTSS: 315 ft/lb $444
- Super Miata Organic Sprung SPM_CKBP_HS: 290 ft/lb $339 + $18 shipping = $357
- FM Level 1: 318 ft/lb: $399
Oh really!?!? Well that changes a few things. I wish these manufacturers would better label their torque ratings. I guess I thought all clutch ratings were crank. So are the ACT ratings crank or wheel?
Anybody know the difference in the FM1 vs FM2 clutch? I have about 300 miles on my FM1 clutch but In the next 1-2k miles, i'll hopefully be in the ~350whp range. Is the clutch disk the same w/ different pressure plate, vice versa, or are both completely different.
I would bet most large manufacturers are quoting crank torque, which will be a higher number. Emilio is a rare bird who values real world application over an inflated number for marketing purposes.
The friction disk that they sell separately says that it is compatible with Level 1 and 2. Based on this I would assume it is the same disk and different pressure plate.
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There was a recent thread where someone's buddy adapted a bigger bore slave from Speedway to his Miata. Aftermarket, but not really plug n play; I think they had to hog out the mounting holes because they didn't quite match the Miata's spacing.
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