4x4ord wrote:
I looked at the numbers a little closer. If the Cummins averaged an rpm where it made 355 hp (that is about the average power that the Cummins produces throughout its rpm range), the Ram had to be 80% efficient at getting the engine's power to the pavement.
The average power that the Powerstroke makes between 1800 and 2800 rpm is 385 hp.
If the Ford was able to run at an rpm where it averaged 385 hp it would have been 72% effecient at putting its power to the pavement. 80/72 = 1.11. You'd expect the Ram to have gotten about 11% better fuel economy. It got 12.5 percent better fuel economy.
Edit: the average hp the Cummins makes from 1800 to 2800 is actually 352 Hp compared to the 355 I used above. That means the Ram could have been 81% efficient at putting its power to the pavement. 81/72=1.125 meaning you'd expect the Ram to get 12.5 % better fuel economy.
I find this very interesting.
Another note that is interesting is that these engines were putting out 352/385 Hp so based on the amount of fuel they are said to have consumed they were running at 42% and 41% efficiency respectively.