Hypothetically, what is max fuel efficiency for the 5.9?

[Crunch]

Regardless whether you believe them or not, there have been many people claiming great mileage with their trucks. I record all mileage and can say that I regularly get low to mid 20s if I keep the RPMs under 2000 on long trips. Assume that all these numbers are correct. People are getting them with the 5. 9 configured to meet government mandates--injection events, amount of fuel, emissions, etc. If there were absolutely no government regulations in play, what would the maximum fuel efficiency be while keeping the horsepower and torque the same for the 2003 model year? I'm thinking it would have to be close to 30MPG. Wouldn't that be something... a thousand mile range!

 

[CMChristensen]

I wish i got 20!! Im going 500-540 miles on a 30 gallon fill up. avg 17mpg is what i always get for some reason.

 

[hdtrukn]

Remember talking to Diesel Dynamics about a 2nd Gen. that they had tuned for 27-28 mpg. If I remember correct

something like 400hp.

Its there its possible OPEC does not want it.

 

[RMalone]

Your already there! Your NOT going to get 30mpg average out of a 7000lb+ truck. Even the first gens running 175hp don't seem to get past the low/mid 20's with virtually no gov. regs involved, and they are lighter than the 3rd gens. At 400hp they sure werent using all that hp and getting 27-28mpg, I've been wrong MANY times but I would really have to see it myself to believe it.

 

[hdtrukn]

2004. 5

19-20 @ 80mph

21-22 @ 70-72mph

run about 1000 week same trip every day

92 miles one way.

overhead is within a 1/10

 

[roperteacher]

I get 21-22 EMPTY hwy in my 07 5. 9. Cruise set on 65. I have the higher gear manual trans, 4x2. . Pretty Ideal conditions...

 

[E7mack96]

I got 24 mpgs going 55-60 mph. this was a 2000 mile run to FL and back. I was very easy on the throttle on acceleration. I got over 700 miles each fillup, and was putting in 29. xx gals at each fillup.



I normally drive it like I stole it and avg 17 like that. I had just wanted to see what she'll do if I drove it differently.



E7

 

[WoodChuck]

I average in the 15s driving like Chuck Andretti.
Low 20s driving like a granny before the bigger turbo.

 

[MickeyMiller]

20. 5 mpg actual, 23. 3 on overhead. 60% hwy,40% in town but not city 'bumper to bumper' driving, all the while trying to keep the pre turbo exhaust temp at/below 600*. 70 mph on the hwy.

 

[Redmega06]

Ok this is frustrating. I just made a trip totalling around 250 miles and only avg 17. 17 at 70mph Has anyone got dodge to correct their overhead guage. I was told that it is within tolerance at 3-5 mpg. Unfortunalty mine is always right at 5.

 

[Vaughn MacKenzie]

Of all the years I've been on this board, there's only been one and maybe two cases of someone breaking 30 MPG with their Dodge Cummins (I think it was fairly legitimate). One I can remember was a 2wd regular cab, '95 or '96 I think traveling across PA on the turnpike, running low-mid 60s. Will have to see if I can find the thread but it was a long time ago (7-8 years ago). Probably had a tailwind and didn't top it off as much refilling

Mike Ramos (MikeR on NW Bombers) turned 28-something with his wife's '95 2wd regular cab once taking a round trip from Seattle to Bellingham WA, running 70 much of the way. Evan Beck was known as "Mileage King" several years ago since he did 27+ a few times with his '98. 5 2wd reg cab auto. Drove like a grandma :-laf

 

[Bachant]

Driving 65 with a light foot I can get 22-23. I've got 25 once but I can't repete. Driving 75 I get 19-20. Over 75 I lose 1mpg for every 5 mph.

 

[Mr.Goat]

Mines an 03 2500 with the 6spd stock. Now that its somewhat broke in at 112K miles I get a consistant 25 mpg not exceeding 60 mph and being easy on the foot. I find once you get over 2000 rpm the mileage drops noticably.



The best I can get is on the highway poking along at 50 to 55 mph. is 28. 2, have done it on several occasions. I hand calculated to get the above numbers. No camper on for the above just the cap.



Interesting enough I have found and still do find a huge difference in the quality of diesel fuel from one area to another. This became especially noticable when I travelled up to the Yukon, Alaska etc. I could loose 3 - 4 mpg by just stopping for fuel.



Several trips to the west coast hauling the camper made a marked improvement in overal milage and engine performance.

 

[Buffalo]

Mr. Dennis Hurst, the head engineer & man in charge of the Cummins Engine Plant in Columbus, IN. told a seminar, which I attended, that the "sweet spot" in these engines was designed to be between 1800 & 1900 rpm's.



Joe F. (Buffalo)

 

[Crunch]

Mr. Dennis Hurst, the head engineer & man in charge of the Cummins Engine Plant in Columbus, IN. told a seminar, which I attended, that the "sweet spot" in these engines was designed to be between 1800 & 1900 rpm's.

I've heard that too, and also heard it applied to most diesel engines in our size range. A few years back someone posted a picture of the world's largest diesel engine. I think it was for a freighter, and ran at about 100RPM.



If we take the claims people are making and graph it out I think we would see roughly the same number of people regularly getting 15-16MPG as people regularly getting 22-23MPG. The top of the bell curve for consistent MPGs will probably be 18-19MPG. At the extreme ends a few people are stuck with 13-14MPG and lower, or are loving their 24-25 MPG and higher. I may have been a bit off when I said 30MPG was attainable. That would be a 20% improvement over the 25MPG extreme. But if our engines were tuned for maximum efficiency rather than the whim of regulators I could see the top of that bell curve in the low 20s for average, consistent fuel economy and upper 20s on the extremes. And we might hear of cracking the 30MPG barrier about as often as we hear about a hole in one in golf.

 

[DCreed]

It doesn't help that we're driving a brick!:-laf stiff skinny highway tread tires, a low profile, smoother or tucked mirrors, and a chin spoiler with a smoothed pointier grill,ect,ect. would help a ton. as well as putting the truck on a diet. We all put 300lb bumpers on, big aux. tanks and big ol mud tires and cry about MPG. It's a TRUCK not a prius!

 

[Cummins Cowboy]

best mileage I have ever seen in a dodge, was my ole single cab '93 2wd 5 speed 1st gen, on a run from salt lake to the northern new mexico border I could pull down 23mpg. alot of it was through moutains and speeds near 80mph. I think 25mpg would have been easy with a constant 60mph. that was a great truck, these days its hard to tell what my truck will really get as I normally drive 80+ where ever I go, and sometime out in the boonies of nevada, I will run over 100, at that speed the fuel really gets sucked down, I bet I am in the 11mpg range or worse when running 100+

 

[JAlderman]

I get about 16 mpg in town stop and go traffic, I try to keep it under 2000 RPM which has served me well. Viginia Beach is head hunting hot rod diesels, smoke and loud pipes will get you pulled here.



I drive by my gauges under 2000 rpm, under or around 600 egt, and under 10 psi will get you the best mpg you can ever hope to find. All that is based on your relation to sea level. Elevation and outside air temp is going to affect everyone differently.

 

[ABarry]

94 2wd Reg Cab 3. 55 Best Ever 27mpg

 

[p-Bar]

What about the hone process these guys are doing on injectors I don't want them squirting more just evenly . Does that make sense. Just don't understand why these fuel mileages are all over the map. I think a lot of the guys try hard like me and never reach the 20 mpg mark