40 mph uphill? Other Armada or Titan TVs?

naturist wrote:

boggerr wrote:
Where is everyone getting the info that a turbo is the answer? A turbo diesel at higher elevations is going to lose turbo efficiency. Less air, less combustion temps = laggy turbo,

RPM’s is the answer. Run higher RPM’s on hills and watch your gauges.

Correct assumptions, incorrect conclusions.

Less air does indeed mean less power. And yes, a turbo does lose efficiency at altitude. But the former is irrelevant and the latter only makes a difference in power output at extreme altitude, where the turbo's efficiency results in loss of pressurization. And a mere 11,000 feet does not do it on the stock turbo on my turbo diesel.

We both quite understand the difference between air at 15 psi (nominal sea level pressure) and air at 11 psi, i.e., at some particular altitude. But the only times my turbo diesel sees either 15 psi or 11 psi is idling at a light or coasting downhill with no throttle. If I mash the go pedal all the way to the floor, the intake air pressure goes up to 38 psi (approximately) and it does that both at sea level and at 11,000 feet. I've measured it. What you are failing to grasp here is that there is no difference in air at 38 psi at sea level and air at 38 psi on top of a mountain.

Over-pressurization is indeed controlled by either a waste gate or a variable vane in the turbo. Both get used to vent excess capacity at low altitudes, and both will get used less and less with high altitudes. Neither is relevant to the engine power output until there is no more excess to waste.