Originally posted by Dan Nixon:
I thought the point of a more complex (expensive) part with an attached but distinct damper ring (as opposed to just making the part just bigger/heavier), with a different distance from crank midpoint was to specifically target bending vibration.


You are correct. That is exactly what it does.

It dampens vibrations in a second frequency mode. Mainly the second mass dampens rumbling noise level which at such low Hz (200-400) is more felt then truly heard. (think bass speakers) Hence why it's more NVH related.

No I have not been able to hunt done any specific specs other then information from two different people that state the mode was chosen for NVH reasons.
One of them works for Ford and the other I don't know. However he knows enough detailed technical information that if he doesn't he is a contractor for them in the engine field.

I agree that less torsional vibration is good for longevity. However that's not to say the stock damper is bad. That is something that is impossible to really quantify.
Does the stock damper allow for 200k miles and the DMD 220k miles???

For that matter then does no damper mean only 100k miles???

We are talking real world driving with a full powertrain attached verses an engine on a test stand... Quantifying longevity would be very hard indeed.

2000 SVT #674 13.47 @ 102 - All Motor! It was not broke; Yet I fixed it anyway.