The VNT ideally takes a lot of inputs and a lot of lookup tables and a PID controller to perform correctly, It's a ballancing act of suffocating the engine, overboost, maintaining target boost over all exhaust flow conditions, preventing boosting against a closed throttle body, effeciency at cruise, probably more I haven't discovered. In a diesel you still have fueling to ultimately control boost, a little trickier in a petrol.Gareth wrote:What about a remote mounted throttle controller? IIRC BMW's had them?There's no currently available electronic VNT controller on the market.
The only one's i've seen are crude pneumatic boost controllers which bleed boost reference into the vac actuator to modulate it. These require the engine to have a vac pump to operate so not ideal for a petrol and have no safeguards. These VNT turbo's on modern cars all run 20-30psi stock so overboost is possible fairly easy