M.R.E. wrote:
I would think the standard Ram diesel would still have the CP3 pump and the HP diesel in the 3500 has the CP4 pump. So don't get the HP diesel.
Because Ram increased the compression ratio on the standard (or "efficiency" version in the medium duty industry I am in) of the 6.7L. Increasing the compression ratio requires higher pressures to remain emissions legal.
Basically here is how it goes. Two things increase Nox emissions, more power and high compression ratios. If you want to make more power, then you have to decrease compression ratios and/or use higher pressure fuel pumps. This will reduce efficiency, but increase power of the engine while still remaining emissions compliant. This is why the high output version of the 6.7L went from 17.3:1 to 16.2:1 in the 2019 engines.
On the flip side, the standard output engines went from 17.3:1 to 19:1. In order for them to make this increase and still remain emissions compliant(even without increasing power) is with a higher pressure fuel pump. So even though the standard output engine does not have as much power, it should be more efficient due to it's much higher compression ratio.
