Thoughts on clutch replacement - w or w/o Flywheel?

[Matticus91]

Less a question about what clutch kit to get, and more about the flywheel. I don't really want to move away from the DMFW (dual-mass flywheel for anyone new) so if it's necessary I'll be getting a new one instead of moving to a SMFW (single-mass flywheel) to avoid the extra costs.

My primary question is; has anyone resurfaced their lower-mileage DMFW instead of replacing it while installing a new clutch? My clutch is still holding strong and the car only has about 70k on it but I'd really like to pop a new (higher-rated) one in there within the next year or so.

I'm aware of the pros/cons for DMFW vs SMFW so I'll list them for anyone searching.

DMFW:

• Pro - Heavier, soaks up vibrations and offers a smoother experience
• Pro - Holds revs more easily (nice for relaxed driving)
• Pro - Very quiet, almost no noise at all
• Con - Heavy, adds weight to drivetrain, rotational mass = power loss
• Con - Revs hang longer, not ideal for track driving

SMFW:

• Pro - Much cheaper than DMFW
• Pro - Lighter, faster revs and quicker rev drops, less rotational mass = less loss of power through drivetrain
• Pro - Can be matched with higher performance clutch set
• Con - Noisy as all hell (clutch chatter), some people don't mind this but lot's who DD their cars have complained or moved back to DMFW
• Con - More vibrations, can be felt through shifter at times/certain RPMs

[Yeineken]

Unsure if it would fit the N55 but you could look into the possibility of using the 1Ms lighter flywheel.

It "may" fit since the 1M uses the same manual transmission from the N55 era cars.

[desertman123]

You know this forum just as well as I, and we're all big proponents of "WHILE YOU'RE IN THERE!!!"

That said, this is a pretty expensive one. You really gotta ask yourself: Is this my sports car, or my sporty daily?

I've heard the single mass in person, and I wouldn't be able to live with it. There's a nice rattle at a dead stop when you're idling with the AC on (and being in metropolitan Florida that will be frequent for me.)

My 2c

[drunkenup]

I would change the fw. It is not mating the surface to the new clutch to be worried about, its the springs and hardware inside the DMFW that wear.

[MightyMouseTech]

Originally Posted by Yeineken

Unsure if it would fit the N55 but you could look into the possibility of using the 1Ms lighter flywheel.

It "may" fit since the 1M uses the same manual transmission from the N55 era cars.

1M uses the N54. Flywheel bolts to engine. N55 and N54 are different unfortunately.

[Yeineken]

Originally Posted by MightyMouseTech

1M uses the N54. Flywheel bolts to engine. N55 and N54 are different unfortunately.

Just remembered another option would be to use the S55 flywheel. A member here used it on their N55/DCT car and I plan to do the same eventually.

* unsure if it'll work for S55 to Manual

[nachob]

Originally Posted by Yeineken

Unsure if it would fit the N55 but you could look into the possibility of using the 1Ms lighter flywheel.

It "may" fit since the 1M uses the same manual transmission from the N55 era cars.

I agree. Check to see if 1M flywheel will fit. It's best of both worlds. Dual mass yet lightened.

If not consider lightening stock dual mass. Find shop that can clean surface of existing one and lighten a bit. You can take pictures of 1M flywheel to see where they took metal off.

[mr.fabulous]

The DMFW in my car makes a constant grumbling noise... sort of like marbles rattling around in a coffee can while the whole thing is smothered in a pillow (this has been discussed in other threads and IIRC others experience the same thing). And the clutch chatters like crazy when hot (I've been driving stick for over 40 years and I cannot get a smooth take-up when it's hot). I expect the thing to explode one of these days. Worst thing about this(my) car.

[Matticus91]

Thanks for the input guys, unfortunately the 1M flywheel will not fit n55 transmissions. I'm probably going to go with the 5-series IS kit (direct bolt-in) and see how it goes. I've heard good things and it's all OE BMW equipment so it's matching quality with a higher torque rating. And, it's a little cheaper, because BMW makes more 5's than 1's

Originally Posted by mr.fabulous

The DMFW in my car makes a constant grumbling noise... sort of like marbles rattling around in a coffee can while the whole thing is smothered in a pillow (this has been discussed in other threads and IIRC others experience the same thing). And the clutch chatters like crazy when hot (I've been driving stick for over 40 years and I cannot get a smooth take-up when it's hot). I expect the thing to explode one of these days. Worst thing about this(my) car.

That doesn't sound normal, I've owned two manual 1ers and driven quite a few others now. Everyone that had the stock DMFW and clutch had a pretty smooth/quiet operation, even when pushing more power through mods/tune.

[MightyMouseTech]

Originally Posted by Matticus91

Thanks for the input guys, unfortunately the 1M flywheel will not fit n55 transmissions. I'm probably going to go with the 5-series IS kit (direct bolt-in) and see how it goes. I've heard good things and it's all OE BMW equipment so it's matching quality with a higher torque rating. And, it's a little cheaper, because BMW makes more 5's than 1's




That doesn't sound normal, I've owned two manual 1ers and driven quite a few others now. Everyone that had the stock DMFW and clutch had a pretty smooth/quiet operation, even when pushing more power through mods/tune.

It is not because of the transmisison. The 1M uses the exact same transmission as the N55 135i.

Good call with the 550 clutch. Will be my replacement if my clutch ever wears out.

[lowbudgethero]

Originally Posted by MightyMouseTech

It is not because of the transmisison. The 1M uses the exact same transmission as the N55 135i.

Good call with the 550 clutch. Will be my replacement if my clutch ever wears out.

this, it's because of the bolt pattern

i went with the 550i clutch kit and a Luk flywheel, dont regret it

[swagon]

So, what would be the symptoms of failing DMFW and clutch, except rattles at idle?

[Matticus91]

Originally Posted by MightyMouseTech

It is not because of the transmisison. The 1M uses the exact same transmission as the N55 135i.

Good call with the 550 clutch. Will be my replacement if my clutch ever wears out.

Originally Posted by lowbudgethero

this, it's because of the bolt pattern

i went with the 550i clutch kit and a Luk flywheel, dont regret it

Great info thanks! I'll look into the Luk FW

Originally Posted by swagon

So, what would be the symptoms of failing DMFW and clutch, except rattles at idle?

Failing flywheel is usually clutch slip at full release, vibrations in the shift lever, chatter, etc... Not too different from clutch failure symptoms. Rattles at idle are actually somewhat common in these cars, especially if everything (AC/music/etc) is off and you're sitting in silence. Vibrations/noise at any speed are not common however