In message , The Natural Philosopher
writes
On 03/07/2019 11:50, Bill wrote:
Where I suspected a resonant frequency of the DMF flywheel masses and
springs, the effect was - for example - when waiting to turn right
across traffic, a gap appears and you let the clutch in sharply, there
a bang and the engine stops dead. I wonder if there is some damping on
the springs which can fail.

Sounds like not enough revs and a too-light flywheel.
DMF is probably a good idea - like IRS - if done properly. I.e. not
swinging rear axles...I suspect the springs masses and damping need
careful tuning and more development that they have in fact had...

The point is that the judder and the bang and stalled engine only happen
on trips where I have been involved in long, multi-stationary crawling
traffic.

I haven't done any tests with over-revving the engine before engaging
the clutch, but I think it used to happen with the older car with
different revs. My impression was that as the clutch engaged fairly
sharply, the engine revs dropped to a point where a resonance caused
conflicting forces at the engine/clutch interface, hence the bang.

The fact that the newer car shows similar, but much less significant
symptoms, might indicate that some development had occurred between 2007
and 2010.
--
Bill