Would it be practical or beneficial to set up the wastegate logic on a turbo motor so that the wastegate stays open until boost is called for?
The way I understand it, the exhaust is always routed through the turbine, which seems like it would take some energy, even when the engine doesn't need more intake pressure than is available via ambient pressure.
There would need to be two alternate routes for intake air, one through the turbo and one skipping the turbo, and some way to balance/mix/transition during changes in demand, but it seems like some combination of BOVs and DVs could be set up to make it happen.
The turbo would want some exhaust flow through it all the time, to keep it warmed up and turning so it would be ready to boost when called for, I suppose.
Ah, well, crap. Someday I'll learn to do a search before I write up a question...
Wastegate Actuator Add to Auto Fuel Efficiency*|*Automotive Discovery
Seems like someone with the right skills could possibly set up a wastegate spring so it would do a similar thing on a conventional system, though. Maybe?