Spike100

I am posting this message in the wrong sub-forum, but it will be understandable here and gain more replies (instead of the Engine/Drivetrain forum where there is less participation and interest is this more mundane clutch discussion). More people will read this article if it is in this section.

At a little over 125k miles, I replaced my transmission and the car’s clutch mechanism. I decided upon a single-mass-flywheel instead of the stock OEM dual-mass-flywheel. I can offer some comments after driving the car for over 100k miles with a dual mass flywheel/clutch, and then driving it now with a single mass flywheel (SMF).

1. The DMF (dual mass flywheel) makes less noise (a lot less noise). The SMF (single mass flywheel) is very noisy.

2. RPM’s drop more quickly (much more so) with the 350z’s DMF vs. the SMF. Upshifting and downshifting is smoother with the SMF. I have a 2003 350z and needed to “blip” the accelerator when down-shifting with the OEM DMF. Shifting and downshifting are much better with the newly installed SMF.

3. The SMF (single mass flywheel) is noisy with the clutch pedal down (engaged) or up (not engaged). It is just simply noisy, making significant racket.

If your goal is a stock car with a quiet transmission/clutch assembly, choose the OEM DMF. If you want a smooth shifting experience, choose the SMF. My strong preference for a 2 seat sport car is the single mass flywheel.

DarkZ03

iTrader: (11)

What flywheel did you get and what weight/material is it?
While DMFs can dampen sound that isn't their job IIRC, they work in a similar manner to the sprung hub of a clutch. Generally the lighter it is the more noise it will make.

LexD

As above-- Which flywheel (brand? material ? weight?), specifically are you comparing the stock DMF to?

I'm planning to install the JWT Nodular Iron Flywheel @ 26lb (along with new JWT clutch & supporting cast) and have read it is a nice middle ground between the DMF and lightweight SMF's.

MicVelo

Installed the JWT iron flywheel on son's car (HR and JK4X trans, notoriously noisy) along with the ZSP HD CSC. No complaints, as little trans noise and chatter as OEM dual mass.

Spike100

Not sure. ...I'll find out. Went with the recommendation of someone in whom I have total confidence. I never asked about the specifics. He told my mechanic what to install. I am very happy with the result.

DarkZ03

iTrader: (11)

Cool let us know so we can continue the talk about this, there isn't really a "bad" choice for the most part. As a mechanic I'd rather not use aluminum for a flywheel unless it's a small, high revving engine that really needs every advantage it can get lol.

MicVelo

For the record (and for the 1,002nd time saying it here ), I hate light weight flywheels for street/highway applications. Race/track, yes, but day in day out use just drives me nuts. Been there, done that... about 40 years ago. My 280Z with a superlight FW lugged, bogged, required way more throttle than I liked (see turbo comment ===>) and generally was not a pleasant car to drive on the street. Especially since it was turbocharged. On the one hand, it was nice to have the motor be able to spin up the turbo quicker but the lack of inertia on the tail end of the motor also killed boost pretty quick making boost building (vs "maintaining") necessary after almost every shift. Went back to a near-factory-weight unit and all was mellow again.

All said, however, I haven't driven a 33 with a lightweight so my feelings on this might be dated and biased by the ONE experience.

DarkZ03

iTrader: (11)

It's not for everyone, I've had an aluminum flywheel on a 4 cylinder a while back and never had any complaints other than the fact that I used a 6puck ceramic clutch disc, and it had no chill. Since it was FWD it was either chattering like a **** or spinning the wheels lol

thekinn

iTrader: (18)

I recently upgraded to a SMF, along with a new CD00A transmission, new slave and master cylinders too, plus a braided clutch line. I came from all-stock configuration. I went with the OSGiken Super-Single clutch/flywheel.. the weight is unknown. I'm experiencing all of the same items the OP and Mic listed. I've had to change the way I drive to avoid the noise.. the thing that is taking the most to get used to is my cruising speed on the street. Where I used to be in 3rd at ~25-30mph, I need to be in 2nd otherwise accelerating from this speed gives me the 'tumbling gravel' noise until I get up over 2500rpm. Same throughout the gears...

I've just gotten to break-in point and hope to experience a track day with it this weekend (projecting rain.. but will still give it a go).

The other surprise was the bucking in reverse getting up the slight incline of my driveway. Needs constant throttle and clutch slipping.. trying to release the clutch fully in reverse makes it feel like the trans is going to fly up through the floor..

DarkZ03

iTrader: (11)

Was exactly my point from what I posted, it's ceramic, they hold nicely when driving to the max but the have no chill. I would get the exedy super single over that one because it is carbon or organic IIRC