RAM EcoDiesel a Flop for Towing

wilber1 wrote:
I never said it was running 40% hotter, I said it had to handle nearly 40% more heat in 17% less time when it climbed that hill. It burned 42% more fuel in 17% less time. That's why I asked what happened to the fuel.

More heat means hotter where I come from. The amount of fuel burned has more to do with the energy density of the fuel types along with how each engine burns its fuel. Diesel engine have a more complete burn than gas due to compression ignition. Then there is the fact that since the Ecoboost has direct injection, it will inject more fuel between strokes to cool things down if needed. The 2.7L Ecoboost did not run any hotter than it was designed to in those tests.

I didn't say it couldn't handle it but the added stress will be bound to affect longevity. You keep going on about how it is built like a diesel, well the Motori is a diesel. Do you think it is made of pot mental?

Yes the 2.7L Ecoboost is built like a diesel, but is not subjected to as much boost pressure, fuel pressure, or cylinder pressure as the Ecodiesel. So do you account for those stresses at all in this little stress calculations you have? Basically they are built with the same materials, but the Ecoboost is under a lot less pressure stresses.

Then you should also know that it is a fundamental advantage a turbo diesel has over a gas engine which directly affects longevity. It can use excess boost for internal engine cooling but the gasser can't because it is tied to a 14.7:1 air fuel ratio.

Wow, you are really bringing out the Wikipedia articles now. A gas engine is not tied to a 14.7:1 ratio, it just runs most efficient at stoichiometric or 14.7:1. A gas engine can run slightly rich to cool the engine off or slightly lean to create more power which also creates more heat.

Also, the longevity of a diesel has a lot to due with how it is "overbuilt" to handle the stresses of compression ignition and it is also due to low engine speeds. As I said earlier, the 2.7L Ecoboost is built like the Ecodiesel, but is not subjected to as much high stresses of compression ignition and it does not need that much engine speed to make the torque needed to normally operate a vehicle or pull a 7,200 lb trailer up a mountain road.

I'm not not mad about anything, the EB does a great job. You just can't accept that there are tradeoffs made for everything. It may be a great engine but it isn't some super mill that can defy the laws of physics.

I never said it defies the laws of physics. All I said that it outperformed the Ecodiesel with power to spare. I also said I didn't understand the trade off with the Ecodiesel since it cost more up front, more in maintenance, and more in fuel costs if I don't tow more than 15% of my annual mileage just to have something with less performance and less capability. It just doesn't make sense to me.

Whatever but there is really no point in exceeding 4000 RPM if peak power is at 3600 RPM and little point in the Cummins turning more than 3000 if it makes peak at 2800 but, if you want to play that game, your Cummins needs 93% of peak RPM to make peak HP. So what was your point again?

I never said anything about what percentage of its max engine speed an engine is at to make its peak power. What I did say was the percentage of usable engine speed each engine needed to pull the 7,200 lbs. In the case of the Ecodiesel, it needed 90% of its usable engine speed while the Ecoboost only used 58% of its usable engine speed with plenty of power to spare if needed.