3L D4D Swirl flaps actuation vacuum

[gulfcountry]

Does anybody know how much vacuum is required to open the swirl flaps ?
Im suspicious my ones have just become inoperative with a noticeable change in low rev engine noise and decel throttling . Above low rpm when turbo boost begins the engine sounds normal as before .
Ive applied vac to the vacuum actuator and can just get to 7in hg and the actuator will not take any more applied vacuum and leaks down soon after applying this amount . The actuation rod does not move at all with this amount although the arm and mechanism freely moves by hand .

[gulfcountry]

Also can anyone confirm if vacuum opens or closes the flaps .