What, exactly is a "dual mass flywheel"?

Chris,
I'm probably wrong but I think it is a flywheel that amounts to two seperate disks conected together with a flexible union. It is supposed to dampen out gear rattle. Experts? They are quite heavy.
Troy

Thank you, that makes sense in a way.

I'm 99% certain that my 951 does not have a dual-mass flywheel.

Same reason the 914 did not get the bigger 6 cylinder, don't want top shelf car less competent than the entry level one. I like the Caymans a lot, but they seem really big to me

That does sound strange. Off-boost, my 951 is a kitten - very very easy to drive at low speeds (or high speeds, for that matter).

That is correct. There was actually a Tech article in the newest EXCELLENCE in which a reader asks about performance mods for late-model 911s, including swapping out the dual-mass flywheel for a more conventional unit. The writer advised against it, claiming that the noise from the gearbox will be so overwhelming at any RPM lower than WOT that the car will sound to most like it's broken.

I read that too in Excellence. I laughed. My 911 rattles like crazy and until I knew what it was, I was concerned. The better throttle response/quicker revving is worth the extra noise. Frankly, it is only noticable at idle with the car in neutral or at very slow speeds. The light flywheel does make the car more difficult to launch or drive at slow speeds because of the off/on feel (less inertial, I guess).

Troy