Lightweight Flywheel Performance vs. Driveability

[Steve97M]

I will soon be installing a new clutch on my '97 which has an MP62 supercharger. While the clutch is being done, I'm thinking of going with a lighter flywheel. I've read different opinions on the performance gains vs. driveability issues. The car is a daily driver and I have no plans to race it. The comments that most concern me are those involving an increased likelihood of stalling due to the engine losing revs while shifting, especially in stop and go driving. I'd appreciate any feedback on this. Thanks in advance for the comments.

[Steve97M]

Just saw the Sticky on this same topic. Looks like the stock flywheel stays. Sorry for any inconvenience.

[Tom @ Fast Forward]

A lot of people disagree with me on the subject but I still think the stock flywheel is the way to go with a MP62, especially a Coldside.

[Gman7007]

I upgraded ONLY the clutch on the 96 a couple of years back and do not regret it. I love the way I can blip the throttle going into a turn and catch the right RPM coming out.

[calichtr]

I was glad to see this thread pop up, but a bit confused about the responses. First let me say that I have zero experience going with light weight flywheels. Also, for the record, I have a 94 Miata (M-Edition, though I believe they are all the same) with 96k miles and no idea which clutch, flywheel, pressure plate are in there as I have only had it for ~1k miles.

The reason for my confusion is... I have been double clutching a variety of cars for many years and when I blip this car, it seems to me that the revs hang too high too long. I am not positive the "fault" is due to the stock/replacement flywheel as it almost seems like possibly it is an ECU feature or something. But I was actually looking forward to going with a lighter flywheel to get away from this feature.

The other things that seems to be missing from this discussion are the weights of the disk & PP. From the short thread http://forum.miata.net/vb/showthread.php?t=255709 it looks like some of the lighter flywheel setup surprisingly add a little weight elsewhere. Also, while all the talk has been about weight, performance is really more a function of Moment Of Inertia. I am pretty sure that drive-ability goes more with the MOI of the flywheel whereas performance goes with the MOI of the whole package so as long as they are strong enough, you would want to go with as light of a PP/clutch disk as possible. I am also pretty sure the 1.6 Miatas had a smaller diameter clutch/PP/FW setup and MOI goes as the diameter squared. Are the 1.6 setup compatible with the 1.8 NAs? Have any of the people here tried this swap?

Based on the advice from this forum, at the moment I am planning on going with a compromise solution with an 11-13 lbs flywheel and unknown disk/PP and strongly considering a 1.6 setup, but more feedback would be greatly appreciated as clearly my experience here is very limited.

[Tom @ Fast Forward]

One reason I think you don't hear much about the Clutch and PP is that it is like Chevys and Fords. Most people seem to like one or the other of the clutch/PP packages and will use it. Therefore, it makes little difference whether you put it on a light flywheel or a heavy one. The key factor is still the flywheel.

"Of course Fords are better than Chevys. I drive a Ford. If Chevys were better, I'd be driving a Chevy. See, that proves it." :) Well, I drive a Miata so the Ford/Chevy controversy doesn't matter. Miatas MUST be the best. If not, I'd be driving a truck. ;)

[lds2002black]

On my 2002 I used the ACT 600240 ProLite flywheel and the AM2-HDSS clutch/pressure plate. I have has no issues with setup. This is a little basised as all my street cars in the past have has light flywheel setups. Just from memory as I can't find the data right now, the flywheel/clutch combination was not a whole lot lighter than the stock setup aas the ACT clutch/pressure plate weighed more than the stock one. I think it was a combined 3-4# lighter than stock .

[Mark]

I've driven other Miata's both on the street and at auto-x's and whenever I came across an aftermarket clutch, it just felt different and made me feel as though if I went with that setup, I'd need a bit of time to adjust my driving style. Right before putting the Coldside on my 95M, I put the ACT clutch and flywheel on. I was quite shocked at how, at least to my left foot/leg, it felt nearly stock. My shifting both up and down felt no different and remained very smooth. If I hadn't had the old worn out parts in front of me, I would have sworn that it hadn't been changed.