Boxster S Clutch - what stage?

[JFP in PA]

Originally Posted by maytag

I didn't say it's ineffective... I said it's a relatively ineffective way to provide harmonic damping / balancing. Which is true. Unless you always have the clutch disengaged.

It is effective at several other things, which, I believe, are the reasons Porsche (and several other manufacturers) have been and continue to use them. I do not believe that the harmonic damping is the driving cause for the use of a dual-mass flywheel for any of the manufacturers or road-going automobiles.

Well, according to Sachs and LUK, two of the largest manufacturers of them, that is exactly why they are used. Google it...…….……

The primary reason Porsche when with it in the 986 is that the M96 engine is also used in the 996, which has a crossmember directly in the way of the front of the engine, requiring as thin a front pulley as possible, thereby precluding a thicker coventional harmonic dampener:

[maytag]

Originally Posted by JFP in PA

Well, according to Sachs and LUK, two of the largest manufacturers of them, that is exactly why they are used. Google it...…….……

The primary reason Porsche when with it in the 986 is that the M96 engine is also used in the 996, which has a crossmember directly in the way of the front of the engine, requiring as thin a front pulley as possible, thereby precluding a thicker coventional harmonic dampener:

Well, if GOOGLE says it....... hehe. Jus' teasin', JFP.

I'm not sure what reference you're finding, BUT, I would bet that it likely says something about "damping" or "absorbing" vibrations in the drivetrain, or driveline, and not specifically the engine. That is the primary purpose of the Dual Mass FW.

I've done a TON of information-gathering on this topic. I've read dozens of papers about the development of Dual Mass fw's; the why's and the wherefore's. I've spoken with manufacturers of both dual mass and single mass, (including one who manufactures both). AND: I've scoured the internet for statistics. You don't have to take my word for anything, but my hope is that people quit presenting as gospel-fact something that just simply doesn't stand-up to scrutiny.

What I have found is that, in ALL OF THE INTERNET, there is ONE, SINGLE, SOLITARY confirmed and DOCUMENTED instance of an M96 crank failure that has been attributed to a LWFW. And even in that instance, the motor in question had countless other modifications. On the other hand: speaking to just ONE manufacturer of a Single-Mass flywheel for the M96/M97 motor, they have sold thousands of them, with not a single claim against them for it being responsible for a motor failure. Not One. and that's only ONE of the mfr's of these LWFW's.

It is very, very easy to find literally HUNDREDS of users of LWFW's in these cars, in America, who have many thousands of miles on them, including many hundreds-of-thousands of racetrack laps, with no ill-effects whatsoever. And when you lay that up against a single documented failure (which remains questionable to me), the fear-mongering just doesn't hold water.

As to the "why they chose to use the least effective method of vibration-damping": your suggestion is that it's because there wasn't room on the front of the motor. Well, my suggestion would be that it's because A) the possibility for harmonic vibration wasn't so great that they felt it warranted a very-mild-redesign of a cross-member, and B) putting it on the front of the motor would have ZERO effect at reducing vibration / harmonics from the drivetrain, which was the primary interest.

Oh, and, would you mind resizing your photos before putting them on here? It's KILLING me, hahahaha.