Originally Posted by poiu
The lower end of that curve is missing, which would show a steep rise in output as the turbo boost comes on. The turbo clearly is working well at 2000 rpm
and the engine
should be burning efficiently and cleanly. Assuming the turbo is working well down to 1800 or maybe less then I don't think you are operating it too slowly. Assuming also your prop is correctly matched. That said, I can't imagine long periods of very slow operation are too harmful. Your engine is probably similar - my engine is used widely in agricultural/construction equipment
and buses for example and they routinely spend many hours at idle.
Peak efficiency and cleanest, leanest, hottest burning should be somewhere approaching the max torque of 2600rpm.
Concerning the prop -- it's a variable pitch
Brunton Autoprop, which should be especially good for getting a load on under any circumstances. Not a Hundested, but the next best thing.