What is the purpose of a dual mass flywheel? - PeachParts Mercedes-Benz Forum

t walgamuth · #1 12-29-2007, 09:21 AM

My SIL just bought a porsche with a dual mass flywheel.. the car needs a clutch. We were discussing the possibility of putting in an earlier stock porsche single mass flywheel or even a lightweight flywheel.

Is the only purpose of the dual mass flywheel quietness of operation?

Tom W

POS · #2 12-29-2007, 09:58 AM

Mostly correct - smoother operation rather than quieter. I can understand the replacement of a dual-mass with a lighter weight flywheel (racing), but if someone can afford a Porsche, then that someone should be able to afford the dual mass flywheel.

BTW, what's "SIL"? Sister in law?

pastmaster · #3 12-29-2007, 05:51 PM

HI Tom, Just thinking about it off the top of my head, I think it has at 2 reasons, an increase in surface and contact area, like a multi-plate clutch, motorcycles use these types today and many of them have a "wet" clutch for wear and cooling purposes. Also allows a smaller flywheel and less mass to accelerate and decelerate.

Two, the mass and weight can be kept down, for accelerating purposes, and flywheel effect, when putting large amounts of power to the transmission, to the differential and finally to wheels and the rubber to the road. And then I guess just because they can.

YIA... Paul

C32AMG · #4 12-29-2007, 06:40 PM

Dual mass Flywheels house dual clutches, more surface area can handle and transfer more engine torque, Dual mass systems are used in high torque engine application, turbo and superchargers. Dual mass flywheels Dampen engine harmonics which can cause gear rattle and drive train vibration. With today’s new clutch technology you could use a high performance single clutch system.

Which Porsche model do you have

t walgamuth · #5 12-29-2007, 08:11 PM

my son in law has a 95 911 which he bought to fix and sell in the spring. It is a rather nice looking pearl white cab with a stick.

It is our impression that the dual mass flywheels are problematic. Is that not correct? I was not aware that it includes a dual plate clutch.

tom W

Xsbank · #6 12-29-2007, 09:03 PM

My Golf TDI has a dual-flywheel, which they replaced once on warranty.

Roncallo · #7 12-29-2007, 09:04 PM

What is a dual mass flywheel. It sound like what I call a multi plate clutch. Is that it.

John Roncallo

C32AMG · #8 12-29-2007, 09:48 PM

Quote:

Originally Posted by t walgamuth

my son in law has a 95 911 which he bought to fix and sell in the spring. It is a rather nice looking pearl white cab with a stick.

It is our impression that the dual mass flywheels are problematic. Is that not correct? I was not aware that it includes a dual plate clutch.

tom W

My mistake, Dual mass flywheel use one clutch disc, Dual clutch systems use two discs. Some how I intermix both systems in my mind. Dual mass flywheel can handle more torque that a conventional clutch system, problematic when the engine may produce more torque (performance modification )than the stock dual mass flywheel can handle
911 is my favorite Porsche

Chas H · #9 12-30-2007, 12:45 AM

Can't the clutch be changed without changing the flywheel? From the link to the LUK site, it appears normal clutch disc and pressure plate are used.

crhenkel · #10 12-30-2007, 01:25 AM

I say if the car has so many issues and it needs a clutch and may have a flywheel problem you should tell him to insure it and leave it out on the street with the keys and the title in the glove box...by the way, what is his address and where will my Porsche be parked, what color is it again????
Other than my dumb joke I have nothing to contribute, good luck with the car, it sounds like it is a nice one. i like the Cabriolets alot.

t walgamuth · #11 12-30-2007, 07:52 AM

I believe the clutch can be changed without changing the flywheel, but the dual mass flywheels have a bit of a reputation for being problematic and after a bit more conversation with him I find that the car might see some track time along the way and so getting rid of the dual mass flywheel would be a good idea. I think having a normal or one piece lightweight flywheel will be considered a plus on resale. Also the dual mass flywheels are not supposed to be resurfacable.

I am told though, that my favorite machinist has developed a way to resurface them. (not surprising).

Thanks to everybody for their comments.

I will pass along my comments to my SIL and daughter and they will do whatever pleases them!

Tom W

POS · #12 12-30-2007, 11:29 AM

The other issue is that the dual mass flywheels can't be turned - when they're worn, you must buy a new clutch kit. I wouldn't recommend "turning" a Porsche flywheel anyways.

t walgamuth · #13 12-31-2007, 08:07 PM

It looks like they are going to go with a fourteen pound flywheel and a heavier duty clutch. The car is a carrera four (AWD) with a 3.6 liter motor and a five speed. I am looking forward to driving it. Maybe they will let me take it to an autocross!

Tom W