Can anyone offer any help? Will my boost valve operate the wastegate and actuator arm whilst revving the engine in neutral or does it have to be in motion?

Engine has to be under load for boost pressure to build.

Not quite, as you snap open the throttle the vacumn disappears on the actuator and it snaps shut, as the turbo spools up you will see a tadge of boost, however you need to release the throttle immediately to stop it going bang so vacumn will then yank open the wastegate and cause the the BOV to trigger

I stuck the back of my car on firm stands, stuck it in 6th then held the engine back with the brakes, this allowed me to see the boost for maybe 5 seconds before the pads started burning Not recommending this approach but it worked for me. The brakes emulate a rolling roads resistance so you can see how many lb's you can build before it vents.

Regards Mark


[Edited on 5/2/12 by mark chandler]

Cheers fellas. To be honest I don't think I've ever heard a turbo spool up but then I've never really listened for one. I don't think my turbo is spooling on my van purely because whenever I've driven cars with them on you can feel the yank when it kicks in. TBH the vacuum pipes leading to the boost valve are pretty grotty and worn around a grip that holds them all together so I've to replace them and have a see then.
Ta.