- Jan 24, 2015
- Reaction score
- Ram Year
- 408 CTD
I don't claim to be an engineer but there's a reason these modern smaller "boosted" engines haven't been offered in heavy duty trucks. I believe testing has proved these smaller engines won't hold up to heavy duty towing. The big 3 would love to get EPA off their a$$ and satisfy customers at the same time by offering an engine that uses less fuel and has more power. If these smaller engines were an option I think we would have already seen them in hd trucks before now.
I worked for various truck and engine manufacturers over the years including Cummins, and you hit the nail on the head. While these engine are great in the duty cycle of a half ton truck, and possibly the duty cycle of an HD truck owner who never tows above 8k lbs, they have to make these engines to with stand the duty cycle of that fleet guy who keeps a 12k trailer hooked up to his truck 90% of the time. That thing would be in heavy to mid boost nearly all of the time.
More boost means more fuel which means more heat. Put that in a small package and you cannot get air in and out quick enough so it starts to dissipate into the oil and coolant causing them to get hot. Put less boost in a larger package and it will move enough air to keep heat in check.
It is like my diesel. High load at low rpms cause the exhaust gas temps to skyrocket because the pistons are not moving fast enough to expel the hot exhaust from all the fuel being dumped(less air displacement per minute). The same load and fuel at higher rpms have a lot lower exhaust gas temps because the engine is moving enough air to keep them low(more air displacement per minute).