[winders]

I suspect the Porsche Factory chose to use the vacuum system because it was less prone to failure than a 12v servo motor strong enough to move the flapper and able to deal with being activated for long periods of time. A solenoid is much less likely to fail.

I'd like to see a servo motor setup that works and is reliable. Has anyone seen such a setup? All of the systems I have seen with a resonance flapper use a vacuum system. As I said, it would sure make things simpler...