[Aussie Mike]

VNT turbos are usually controlled by the ECU. They either actuate the vanes via an electric actuator or a vacuum diaphragm and solenoid valve setup.

This setup has been simplified. The bloke I bought the turbo from modifies them and adds a boost diaphragm rather than vacuum. He then just sets the max boost pressure and locks it off. The turbo will spool up to the pre set max boost and just sit there through the rev range.

There was probably a fair bit of experimentation to get the right boost diaphragm to work. Seems to work fine so far. It'll be interesting to get it fine tuned on the Dyno.

Cheers