Quote:
Originally Posted by jayno20
So people are saying this "flutter" is caused by the solid coupler? Anyone have a video of this noise?
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I don't have anything of the noise
in situ, but here's the cause:
Video
If you take the belt off and twist the pulley back-and-forth rapidly, do you get any noise? There's clearance in mine - not much at all, it would be difficult to measure in terms of angular displacement - but the conditions where the rattle occurs seem to create a resonance or oscillation where the rotors are transitioning between being driven and bouncing off the other side of the lash due to inertia. The spring in the original coupler kept 'positive force' on the gear set so this wouldn't happen.
I wonder if all it would take to fix this is for the ECM to command the bypass valve to partially close under these conditions, to put just enough load on the rotors to keep them damped.