diesel turbo

[jamer]

how does a dump valve work on a diesel? where does it get the vacum from?

[Clanad]

The kits that I've seen are all electronically activated... no vauum. Additionally, the prevailing wisdom is that a dump valve on a turbo-diesel defeats the purpose and control of the turbo but does satisfy some misplaced need to hear the wooshing sound when the throttle is closed...

[MrBiggles]

From what I know most Diesel engines do no have a throttle and as such will continue to suck air even when you take the foot off the accelerator. Hence there is no need for a wastegate.
I believe there are some that do have a throttle and valve but they are probably electronically controlled by pressure sensors. Have you checked whether your engine really uses a throttle and a wastegate? You may be looking for something that isn't there.