40 mph uphill? Other Armada or Titan TVs?

richclover wrote:


The short answer is “yes”. I haven’t researched the engineering but I expect that my Turbo Cummins will make rated horsepower on I80 at 8000+ feet elevation in Wyoming. Same on I95 in Florida, but with little or no turbo boost.

My 235 hp Lycoming aircraft engine was rated at 2400 rpm and red lined at 31” manifold pressure. With the simple, manually controlled wastegate it would produce close to rated horsepower to 20,000’.

Agreed, rpm will affect turbo output, but given an appropriate control system and normal operating rpm ranges, I wouldn’t think it would affect automotive engine output that much. Peak torque output is certainly affected by rpm, IMHO.

Here’s an excerpt from the Wikipedia article on turbos:

“... A reduced density of intake air is caused by the loss of atmospheric density seen with elevated altitudes. Thus, a natural use of the turbocharger is with aircraft engines. As an aircraft climbs to higher altitudes, the pressure of the surrounding air quickly falls off. At 18,000 feet (5,500 m), the air is at half the pressure of sea level, which means that the engine produces less than half-power at this altitude.[20] In aircraft engines, turbocharging is commonly used to maintain manifold pressure as altitude increases (i.e. to compensate for lower-density air at higher altitudes). Since atmospheric pressure reduces as the aircraft climbs, power drops as a function of altitude in normally aspirated engines. Systems that use a turbocharger to maintain an engine's sea-level power output are called turbo-normalized systems. Generally, a turbo-normalized system attempts to maintain a manifold pressure of 29.5 inches of mercury (100 kPa).[20]...”

Well, I know absolutely nothing about turbo planes so I can’t compare it with a diesel truck. I understand what you are saying and am not arguing with anyone that a turbo is not going to out perform a N/A engine so if I’m coming across that way I do apologize.
What I’m trying to get at is RPM’s are your friend either with a turbo or N/A engine.
A turbo diesel will lose peak HP and torque at higher elevations but with all the newer technology it’s not as noticeable as older diesels. The one thing I have always encouraged folks with a diesel that are pulling loads is to install a EGT gauge and drive by that, especially at higher elevations and grades, I guarantee that most of those who are pushing their trucks up hill will slow down cause they are downshifting to increase RPM’s and get that turbo spooling at its sweet spot