New Ram/Cummins vs GM/Duramax on the IKE

ShinerBock wrote:

RCMAN46 wrote:

Actually the Duramax reaches max torque (1600 rpm) at 200 rpm less than the Cummins (1800 rpm). Both engines produce max horsepower at the same 2800 rpm.

True, but the Cummins produces 90 lb-ft more torque at 1,800 rpm and more than likely produces the same amount of torque as the Duramax does at 1,600 rpm.

The other thing is that the Cummins is more of a natural torque at lower rpms while the Duramax is boost assisted torque at lower rpms. This does mean much in a wide open throttle situation where the short stroke Duramax shines, but at part throttle under normal driving conditions you can feel that Cummins has a lot more natural torque between 1,100 and 1,600 rpm without the need of the turbo spooling that much to make it.

If you have ever driven a Duramax(or Powerstroke) and a Cummins back to back then you will know what I mean. My Cummins(even stock) will just pull me up a long hill close to my house at 1,250 rpm at 60 mph the whole way up with little boost while my cousins tuned LML would build boost and then eventually downshift half way up to maintain 60 mph. My Father in laws new 2018 Powerstroke would do the same, but will hold 6th a little longer. This is probably why people say that the Cummins pulled like a train because it does so with little effort at low rpms versus many other diesels I have driven.

Not saying that it is a bad thing tat a Duramax has less natural torque, it is just a product of it's design and how these two engines drive different under normal driving conditions. Wide open throttle, the Duramax will win especially if the Cummins has a slow shifting Aisin behind it. The thing feels like it takes forever to shift under wide open throttle versus my 68RFE.

This conversation should be about the Duramax L5P and the current cummins with the CP4 and reduced compression. I'm hearing reports that the latest cummins is making less fuel mileage than the previous generation and maybe requiring more turbo boost now to make equivalent power.

As for performance of these two trucks they're overall performance is essentially the same. V8 or I6 doesn't matter with the end result.