Ford 6.7L 1050 ft lbs TQ at 1,600 rpm, 475 HP at 2,800 rpm

4x4ord wrote:
The industrial diesels move a little more air per HP but when you actually do the math the numbers might surprise you.

A Cat C13 can be speced to produce 520 HP (and we have Cat C13s in some of our equipment where they produce up to 543 HP) The C13s produce peak HP from 1800 rpm to 2100. So it is designed to run all day long delivering 520 HP @ 1800 rpm.

The C13 has a displacement of 12.5 liters. So at 1800 rpm it can produce 520/(1800 x 12.5) = .023 HP/rpm liter. If the Powerstroke were tuned to produce .023 HP/rpm liter it would make 431 HP (.023 x 2800 x 6.7). So although the industrial engine at 1800 rpm produces less power per litre displacement it doesn't pump a whole lot more air per HP produced when compared to the Powerstroke at 2800 rpm.

You'd also have to factor in boost and volumetric effciency with those calculations. By your math, I'd guess the PS has higher boost as it makes more hp/rpm/L. Plus at high rpm the VE is usually lower, so it needs even more boost to overcome that.