Just got back from the Cummins Customer Appreciation event in New Braunfels, TX. Cummins got an ear full from 6.7L owners about Fuel economy vs. their older 5.9. Cummins said the goal was to meet the same economy with the 6.7 as the 5.9, however they realize the mark as been missed. They noted that all diesel manufactures are suffering to meet the EPA guidelines. In their words "Either we evolve or we go out of business." The majority if not all 6.7 owners acknowledged that the 6.7 was stronger and pulled better (6.7 with 6pd auto) vs the older 5.9 with 4 spd auto.

So the question is, would you buy a less powerful version of the 6.7 in exchange for fuel economy?

 

Let's see.....

A more expensive system with less power........

I'm gonna have to say, "I'm glad I own my '06 5.9!"

That's the same BS that Ford did with the 6.0. The '03's and '04's had butt loads of issues and so instead of fixing the problem and giving the customer what they paid for (i.e HP & TQ), they de-rated it and came up with a bunch of band-aids. 73 friggin TSB's and re-calls.

I understand that they are all trying to meet the emissions crap, but nobody is gonna pay the money these things cost for a de-rated engine.

 

My friend owns a I think it's a 97 Ford diesel. It has well over 100K on it, and he says he still gets about 28mpg consistently. It isn't modded, and is basicaly a work truck. He claims that his is the very last year that Ford made a good diesel truck, and from then on it all went downhill.

I'm beginning to think that maybe Dodge is on the same rail.

 

I also have a 06 5.9L. Cummins throughly explained how the 6.7 burns more fuel while heating up the systems in the exhaust to burn off the emissions when its doing its cleaning cycle. It sounds like the 6.7 without the emissions add ons (which they had to do to meet 2007 emissions) would actually get even better MPG than the 5.9. So perhaps they need to rethink heating an entire engine worth of fuel when perhaps they could just be heating the particulate filter with perhaps an electric grid or a gas grill under the particulate filter. Just my observation from their presentation. Cummins did say when they designed the engine it wasn't really for you to go to the grocery store, it was for you to tow a 5th wheel, it which case a cleaning cycle wouldn't be necessary due to the heat generated by that task.

 

Mayfair,
I don't think your buddy gets 28mpg. If he's telling the truth, he could have an article in every diesel and full size truck mag in the US.

 

The reason that 6.7L have such poor MPG numbers... You got to remember that 6.7L truck tend to have 3 injection events now... Pilot injection (to remove knock), the main event (Firing), then the Regen event (fired in the exhaust stroke).

I'm glad I've got a old school 5.9L 24V... I'm pulling 21-22 MPG and not going to even look at the fututre truck I think there junk... I'm building as much power as the stock 6.7L now... Why bother...

Check sig...

As for the 28 MPG that is hard to believe... With a 35 gallon tank that would be 980 miles on a tank of fuel... Even at my 21 MPG and 35 gallons 735 miles... Which is believeable...

 

it might also depend on how that ford (28 mpg) truck is setup... if it's std cab 2wd I could see it... ran into a shop owner with a 12v Ram that was claiming 25~26 out of his... 2wd std cab...

 

i believe the 5.9l has 3 injection events and the 6.7l has 5. that is how they quieted the 5.9l down in the first place

 

Oilwhore, you are correct. The 6.7L has five injection events normally, and during regeneration there is a sixth injection that chases the exhaust gases to make the exhaust richer. The five injection events is what makes the 6.7L so smooth.

 

Well I was close on the count... (At least I had a clue... [sm=interesting.gif])

But regardless of how many events its still pumping a lot more fuel per cylinder stroke...