2021 Ram 3500 H.O.

4x4ord wrote:
It really isn’t about favourite brand truck for me. I realize that had Ram not stuck the 5.9 Cummins under its hood back in 89 we might not have seen the Duramax. Had we not seen the Duramax or the Cummins in Ram and Chevy who knows what Ford would be trying to pass off as a diesel in their pickup. So I really appreciate what competition amongst the three has done. I am not impressed with Cummins in the big truck arena where the newer Cummins engines are referred to as boat anchors.... that might prevent me from placing the 6.7 Cummins on a pedestal like many Ram guys do. I am kind of placing the Powerstroke on a pedestal, not because it’s Ford, but because I believe the 6.7 Powerstroke has almost done for the pickups what the 5.9 Cummins did in the 90s and the Duramax did in the 2000s. It was first to introduce the compacted iron block, Ford was bold enough to incorporate reverse flow heads, they are first to have steel pistons. I believe the Powerstroke has raised the bar as far as cooling is concerned. Until I looked into it in the last few days I didn’t realize how large the radiator and charge air radiator were on the Ford. There is a huge difference in the physical size of cooling system components between the Ram and Ford. (Unless Ram has very recently upgraded?). The heat soaking is not going to be an issue when the intercooler has its own radiator.... and the secondary radiator is significantly larger than the air to air on the Ram. The Ford primary radiator has double the surface area as the Ram rad. With steel pistons Ford might even be allowing hotter egts than they did in the past. The 2020 Ford might not defuel as much as you think on a hot day,

In the big truck arena, Cummins actually sales a lot more and has a lot larger market share than the others by far. Especially for our customers looking for high horsepower for their application. These are not based on my beliefs or opinions either. They are based on sales data provided by HDAA along with sales data from our 130+ medium and heavy duty dealerships. So don't confuse your bias opinions as facts. I will also say that the 6.7L Cummins has been the highest selling engine in medium duty truck and buses since it has been out. Mainly because it makes more sustained and rated power than the other engines, like the 6.7L Powerstroke, in these applications.

You still have a lot to learn about engines. For one, it is not just how big their cooling system is, but also how cool the incoming air is, how quickly it can move that air through the system, and how much of that heat is retained. That is different between each engine along with intake and emissions system design. One design may get hot enough to need things like steel pistons while another may not. One design may have a more restrictive turbine housing on their turbo for quicker spool causing higher EGT's while another may not.

It is not as simple as you think it is and one system can be effected by multiple systems so basing assumptions off of the specs of one system is only telling part of the story. For example, due to the reverse flow design of the 6.7L Powerstroke, it may need that larger cooling system to accommodate for the high localized heat on the upper portion of the engine like the heads. Or, also due to the reverse flow design, you may have a more restricting intake manifold like some of the earlier 6.7L did to to fit the 6.7L in the engine bay. This restriction will cause higher EGT's.

Then there is the engine design itself. Certain engine design generally run hotter than others. I will say, that heat and cooling system requirements/design is one the reasons why V8 engines like the Cat 3408 never made it in the heavy duty truck industry and it is dominated by inline engines. Same with larger generators. The inline systems do not require as big of a cooling system to keep them cool. So just saying that one engine is better based on cooling capacity is really an ignorant way of looking at it.

Also, heat soaking is an issue on all water cooled intercoolers under sustained loads regardless of whether or not they have their own cooling system. The benefits of a water cooled system is better short burst power like in drag racing/tractor pulls or posting high power numbers on the dyno.