Throw Away Diesels.... THANK YOU CUMMINS!

[dpuckett]

I still maintain that even though the 6. 7 is bigger, potentially, it could get the same MPGs as the 5. 9, due to the fact that it is the power USED, not available tha tdetermines MPGs, and I dont think displacement has a whole lot to do with the entire equation.



I was led to believe that it'll get 2-3MPG better than the competitors' 07 engines. Though it wont make much difference- neither newer V8 is known for outstanding MPGs.



Daniel

 

[EMD-Run8]

Yeah, maybe they made a really good flowing cylinder head for this motor. In regard to "throw away motors", did you read in the Diesel Power shootout about the guy who won with the DMAX? He's gonna go back and rebuild with better rods, pistons, etc. . Yet the fastest Cummins racers in the country are using stock cranks, rods and pistons and holding together fine! That speaks volumes right there.

 

[WDaniels]

RGardner is right. It is only . 8 liter larger. I dood gooder in new math.

WD.

DPuckett,

I fail to understand your logic. Larger engine, heaver engine parts with less total oxygen getting to the engine does not make for increased mileage. It takes more fuel to operate a engine that is that much larger. That is the nature of the beast, bigger displacement, more torque and more hp in internal combustion engines require more fuel. I think that is the reason Cummmins went to a larger engine is because of the recirculating EGR reducing power. I also know that the variable vane turbo will help some, but not that much. What I want to know is how the rigging on the vanes will be regulated. Fuel pressure or demand? Air flow? EGT's? We will see.

WD

 

[rbattelle]

According to Diesel Progress, most manufacturers are increasing displacement to replace power lost from Tier III emissions.



Ryan

 

[Cummins Pilot]

it could get the same MPGs as the 5. 9, due to the fact that it is the power USED, not available tha tdetermines MPGs

Isn't that what I said???

 

[Wetspirit]

It is hard to be confident that the new engines will get better mileage. But the 04. 5-06 engines have been getting worse mileage than they should. The third injection and retarded timing are, probably, a couple of reasons.



It's not about getting better mileage while producing more power, it's about getting better mileage under the same circumstances.



Since the displacement is bigger there will be more internal friction to overcome but that may be outweighed by more efficient running. The turbo might be part of it if it produces more boost with less drive pressure. The particulate trap may remove the need for the third injection event. So even if there is a purge fire in the trap occasionally, it may add up to less fuel used overall. And with EGR they might be able to advance the timing some.



If all this emissions stuff just keeps making them run worse and get worse mileage, the advantages of the diesel engine will just fade away.



Wetspirit