CamperAndy

Yep that's me. I do like to debate (argue if you must) so that I can sometimes be educated and sometimes educate someone else. In the case of this thread I think I can contribute positive information.

The laws of physics do not care if you have a mighty CTD or not. The loss is still there until you compensate for it by adding boost but there is a limit to what you can add. There is also the fact that different turbos have different performance curves and some just really do not like thin air.

I had never heard of a 1.2% loss and since it was so exact I just wanted to know what it was based on, is that too much to ask.

etn550

The turbocharged diesel is naturally altitude compensating. The higher you go the lighter the air so the turbo spins faster to make the same or close to the same boost. The side effect is that eventually at a high enough altitude the turbo will overspeed and fail catestrophicly (sp). So.. If you are stock you are ok and could check with Cummins or Dodge for the max altitude. For CAT it was full rated power up to 7,500ft. I mention this because many on here mod the engines and any mod that is going to drive the turbo harder will bring it closer to the turbo rpm limit quicker as altitude increases.

Now.. Is our ECM smart enough to know the speed limit based on the inlet pressure and engine parameters and fuel back??? I don't know. It seems like the required sensor information is available to the ECM.

The natural altitude compensation is one reason later piston military aircraft could go higher and maintain HP.

RiverRat2

Good advice,,, Yes ease out of the throttle!!!!!