Quote Originally Posted by Chaz View Post
Ben81C,

It sounds like none of your mechanic mates or diesel specialist are familiar with the VNT controlled turbochargers used in almost all late model diesel cars. Variable nozzle turbochargers don’t use or have a wastegate and unlike a conventional wastegated turbocharger, they’re controlled by vacuum rather than pressure. Controlling boost with a wastegate is easy and in that case I would agree that an electronic controller is the better option, but in our case, and the ZD30 Patrols VNT unit, this doesn’t apply.

The main reason we fit a Dawes TDi controller is to enable bypassing the ECU control solenoid after blocking the EGR. The Dawes valve does control boost well and many people use them with good results. It’s just something fairly new that not too many diesel mechanics may be familiar with unless they frequent the Patrol or VW forums. Initially the TDi valves were produced for TDi VW Golf and Jeda cars in the USA, but they are also ideal for the ZD30 Patrol with its VNT turbocharger.
Ah that is the missing info from the set up and explain diagram everybody has missed and why every one has been scratching their heads, this has cleared the air well and truly. Its easy to make decisions when you have the whole story and have a clear idea of how things work. Great explanation and thank you for filling in the blanks Chaz. I will get one ordered ASAP. Thank you all.