technicalninja

I've searched and only found one thread regarding my question and it really doesn't answer it.

http://www.miataturbo.net/suspension...trength-83376/

My question is NOT regarding which way is better just simply...

Has anyone had a stock 1.8 flywheel fail?
If so, how, what power level, what RPM?
Please provide details if possible.
Is there a "safety" factor in choosing an aftermarket flywheel?
I would prefer SFI certified stuff but if no-ones had an actually failure with a stock flywheel then it's a moot point.
Thanks in advance.

sonofthehill

iTrader: (1)

Ok Tech, I have a data point or two. I have been running a stock flywheel for a while now. I originally swapped out my light weight SFI flywheel in an attempt to increase the life of my transmissions. It seems to give about a 4 to 5 X increase in lifespan over the lighter one, in my experience. I think I have an excedy flywheel as my old one, not sure how much it weighs. My last 5 speed failed and the stock flywheel looked fine and it is currently engaging my 6 speed, so far so good, might fail before November, we'll see.

sonofthehill

iTrader: (1)

I don't run past 7000 much except across the finish line for a moment to about 7300.

technicalninja

That's exactly the type of data I'm after. Thanks so much!
It's even MORE interesting in that you saw a decrease in transmission failures!
I'm slowly coming to the point of staying AWAY from lightweight clutch/flywheel assemblies because the data looks like ALL of the manufactures are moving to insanely heavy dual mass set ups as standard equipment.
The power loss from a heavy flywheel is easy to demonstrate. You will usually be a little tiny bit faster with LW stuff but...
If it really doesn't matter (street car) it seems going lighter is also going "harder" on the driveline.
I'm also a believer that the vibrations inherent in an engine are attenuated better by a larger mass.
This may help oil pump life...
Big heavy flywheels make any engine "smoother".

My only worry was "Is the stock flywheel STRONG enough"
PatsMX5 is my first data point as he successfully use a stock flywheel and he boosts HARD!
You are my second (with the juicy 4X tranny life comment).
You beat the **** out of your car as well.
Your data is "gold plated".

When one guy sees something it can be a fluke.
When two guys see the same thing it is FAR more real...

I'm going to use stock 1.8 flywheels on my builds as I can now see too many "side effects" from lightweight stuff.

This is not saying lightweight flywheels are bad, just not needed in my application.

That is...
Until someone remarks "I had one come apart on me, come up through the tunnel, barely missed my foot" and I'll start looking for the heaviest steel performance flywheel I can find.
I think FM has a "heavy" or did at one time...

sonofthehill

iTrader: (1)

Pat has pushed his car way harder than mine.
Lol, I love posting this.



Don't try this at home kids

patsmx5

iTrader: (16)

I replaced mine once when swapping clutches, as I had a stock flywheel with 39k miles on it that was mint. That mint flywheel, I put maybe 10k miles with a 6 puck and ACT Extreme, with enough power to slip it. 7K & 20 PSI holeshots, 9k rpm shifts, etc. Beat on it.

When I pulled the clutch, the clutch was ok, but the flywheel had many many cracks all over the surface. I broke it with a hammer and threw it away so nobody would ever reuse it.

My guess, I overheated it from slipping the clutch. I bet it would have esploded had I kept using it.

My recommendation, don't go over 9k, and don't let the clutch slip much, and if you do, plan on inspecting the flywheel periodically.

This is how I launched, 20 PSI and 7K on this launch.

technicalninja

You scared the hell out me!
That's what I'm trying to AVOID but...
That's NOT a Miata!

I once saw a REAL 66 GT350R do that **** at a historic race at Green Valley just before that track shut down.
I was a "Security Guard" at the last big event held there (I would have done it for FREE, they paid me) and the GT350R chucked it's **** completely through the front window!
The flywheel went 200+ feet away from the car!
Looked like the scene in Alien...
Did a serious HURT on an iconic car.

Not for me at all...
I'd prefer a SFI flywheel.
What I'd really like is an SFI Scatter Shield (bell housing).
That's just not available for a Miata...

technicalninja

Thank you for the input Pat.
I'm limiting to 7500 rpm with a 7000 rpm shift point.
I'm a bunch closer to SOH than you but I'm not going to spend ALL of my extra money at my local dragstrip.
I would bet my car will see 1/10 what SOH does and 1/50 of what your car does.
Much lower "duty cycle".