alex

DMF seems to be making noises upon clutch pedal release, and clutch needs attention anyway. I'm not spending $2k or whatever on one of the few OEM DMFs available. I've read post after post about the vibrations and rattling from the 13lb fidanza unit, and that the 18lb RS barn isn't as bad, but they are OOS anyway. What I haven't found are any reviews for the 25 lb Spec Steel flywheel. It's still 7lb lighter than stock, so maybe there will even be a slight performance improvement, but really I want drivability and reliability. My car has too many miles to introduce anything that's going to unduly accelerate wear. So... Anyone care to chime in with experience or even theoretical postulations?

T&T Racing

I am assuming this is a street car. If so, the best option is the OEM flywheel, smoother idle.

V2Rocket

Solid flywheel paired with a new RSBarn harmonic damper (crank pulley) and you'll be good to go.
I have a 9lb aluminum FW on my 2.9L paired with the RSBarn damper and it is smooth at all RPM.

alex

Indeed, and if they didn't cost $2000+, it would be a no brainier. Just can't swing it... Or I guess I could if I had to, just can't stomach it.

Hey Spencer, I assume the increased stroke to get to 2.9 puts your engine in the same type of situation as the 3.0 with regard to vibration? I didn't know that there was an aftermarket harmonic balancer... Last thing I read on it said that the S2 balancers were NLA, so that is something to look into. Thanks!

V2Rocket

Yes, I have a 103mm bore and a 88mm stroke (3 liter crankshaft) so same harmonic boat.

http://www.rsbarn.com/catalog/index....roducts_id=103

T&T Racing

Contact Brandon @California Clutch
https://californiaclutch.com/?v=f24485ae434a
CC machined a 944 light weight steel flywheel

s85b50

My M3s with LTW flywheel judders like there is no tomorrow at idle even with spring clutches... Is it any different for transaxles?

Zirconocene

@s85b50 : It won't make a difference because of the transaxle, but I'm surprised about your M3s. My E60 M5, even with the clutch at the end of its life (and presumably the dual mass flywheel, as well) is OK at idle. Getting into first is juddery, but not idle. Maybe I didn't understand what LTW means.

Cheers

s85b50

Aftermarket lightweight flywheel. Stock dual mass has dampening rubbers inside that wear out over time but smoothen the idle. Inline 4s are also very rough vs. 6/8/10 cylinder engines.

V2Rocket

968 uses a 60-2 trigger wheel on the flywheel that the 944 FW won't work for.

My 9lb aluminum Spec flywheel with steel insert doesn't have any judder - it's quite smooth-engaging, actually. It is mated to a standard 944 NA Sachs clutch kit.

s85b50

I don't know if judder is the right word, more like it rattles like a diesel if I don't depress the clutch.

Zirconocene

@s85b50 : I see, it's THOSE M3s. Very nice and understood.

Good luck

V2Rocket

That sounds like a DMFW going bad, but don't know why your BMW with a solid FW would do it.

944 solid FW with the harmonic damper on the front of the crank does not rattle or anything like that.

s85b50

This is how it sounds. Not my video, but very similar. Apparently the stock dual mass flywheel eliminates this completely with BMW's NVH design, so I was wondering if 944 design was similar to this.

Zirconocene

DMF or not, it shouldn't sound like that on the 944. At least, it sure doesn't on my car, which did not benefit from the 968 DMF.