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I've looked at various posts here but still have questions. A fellow I spoke to this weekend has the new 6.7 diesel 4x4 3500. This is his fourth Dodge Cummins. Although he likes the truck, he said he would not buy another one. Next time he'll buy a gas engine. The main reason is the poor fuel economy. He said it is about 30% worse than his previous 5.9 litre diesel.

Although I would like a new truck, this is scaring me off of buying a 6.7. Are others having similar experiences?

What can one realistically expect in terms of MPG from a 5.9 and a 6.7, running empty and pulling a 10,000 pound enclosed trailer?
 

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i love my 6.7 but if youre wanting the fuel economy go with a 5.9
 

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Depends on modded vs. stock. My last stock tank I was empty doing 80 mph and got 16.3. My first modded tank was pretty bad, 14.8 but this current tank seems to be around 18. There are lots of factors involved in mpg's. If you were to get a 6.7, you must remove all emissions stuff to get better mileage, and that will void the warranty. It's a tough choice. I went through the same thing for months. I settled on a barely used 5.9. I got a great deal on it. I was a heartbeat away from buying a 6.7 though. This decision will make you go crazy....:ah:....But if you're towing 10K DO NOT BUY GAS!!! Even though diesel is more expensive per gallon, gas (when towing) will be more expensive per mile. Good luck. :thumbsup
 

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I Got 10 Mpg With My 5.9 And I'm Getting 10.3 Pulling The Same Load Of 11,000 Lbs. Empty I Was Getting 20 With My 5.9 With My 6.7 I'm Getting 18 ,if I'd Change My Intake To Something Like A K&n Or Air Raid ,i Positive I'd Geta Little Better Pulling For Sure,empty Mabey The Same Or More?
 

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I Got 10 Mpg With My 5.9 And I'm Getting 10.3 Pulling The Same Load Of 11,000 Lbs. Empty I Was Getting 20 With My 5.9 With My 6.7 I'm Getting 18 ,if I'd Change My Intake To Something Like A K&n Or Air Raid ,i Positive I'd Geta Little Better Pulling For Sure,empty Mabey The Same Or More?
Were those numbers hand calculated?
 

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there has to be at least half a dozen other topics asking this same question. Try searching throught the section a little. Tons of great info there.
 

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I've looked at various posts here but still have questions. A fellow I spoke to this weekend has the new 6.7 diesel 4x4 3500. This is his fourth Dodge Cummins. Although he likes the truck, he said he would not buy another one. Next time he'll buy a gas engine. The main reason is the poor fuel economy. He said it is about 30% worse than his previous 5.9 litre diesel.

Although I would like a new truck, this is scaring me off of buying a 6.7. Are others having similar experiences?

What can one realistically expect in terms of MPG from a 5.9 and a 6.7, running empty and pulling a 10,000 pound enclosed trailer?
How many miles does his 6.7 have on it??? I mean its a Diesel its gonna take a while to get it broke in and get the fuel mileage up!
 

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I Only Have 5000 On The 6.7 Bone Stock.my Old 5.9 Had 140,000 Before I Wrecked It.YES THOSE NUMBERS ARE HAND CALCULATED HOW ELSE COULD YOU DO IT.ANYTHING ELSE JUST DOES NOT COUNT!
 
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This is my 5th 5.9. I had 2 12 valves, 2 24 valves and now the 6.7.

Knowing what I know now, I wish I had my 04 back. 16 MPG local vs. 10? 20 MPG highway vs. 14? Well there's a DUH! I might dump this for a low mileage 5.9 and put the goodies in it this one has. Makes no sense to me at all why these tree huggers have to attack such a small piece of the polution problem. The 04's hardly smoked and still got 20 MPG.
 

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Polaraco, that sounds like a dramatic drop in mileage from your '04 to the '07 6.7 litre. Your experiences sound very similar to those of the fellow I spoke to a few days ago.

So, I'm wondering if all the 5.9's, until they stopped making them part way through the '07 model year got good MPG. Or did they become worse between '04 and the end of the engine run?
 
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You bet Swampy. . . VERY disappointing. All the figures made sense with the 6 speed. Lower high gear RPM's is supposed to mean Higher MPG. And in the 5.9 days, I have to think that is true.

It's probably these tree huggers pasification process we go through. (Regen's)

You'd have to look for something in the parts books to see if the 03 to early 07's were the same. Seems to me there was a change in 06. But I never heard anyone complain about mileage. It may have been a exhaust change.

Wish I could flip back the clock a year. . . .
 
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I Got 10 Mpg With My 5.9 And I'm Getting 10.3 Pulling The Same Load Of 11,000 Lbs. Empty I Was Getting 20 With My 5.9 With My 6.7 I'm Getting 18 ,if I'd Change My Intake To Something Like A K&n Or Air Raid ,i Positive I'd Geta Little Better Pulling For Sure,empty Mabey The Same Or More?

Fisher

Yep an aftermarket air cleaner will help a bit. It will lower the EGT's a bit. When I did it on my 04, I noticed less smoke. I would think that would enhance the combustion and maybe cut down on the fuel robbing Regens.

I just dropped 300 yesterday to see if that theory still holds water
 

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I am new to this forum but not to Dodge Cummins Trucks or Powerstrokes for that matter. I own a pallet business and pull some serious weight on a daily bases. I don’t compromise the integrity of my trucks by adding any aftermarket mod’s... So the only comparisons I can make with my trucks will be in stock fashion. I own 5 Dodge Cummins trucks and 1 Powerstroke. I must say that I clearly prefer the Cummins over the powerstroke due to reliability, low end torque (i pull heavy trailers) and mpg. The trucks I own are listed below.
 

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I am new to this forum but not to Dodge Cummins Trucks or Powerstrokes for that matter. I own a pallet business and pull some serious weight on a daily bases. I dont comprimise the integrity of my trucks by adding any after market mods... So the only comparisons I can make with my trucks will be in stock fashion. I own 5 Dodge Cummins trucks and 1 Powerstroke. I must say that I clearly prefer the cummins over the powerstroke due to reliability, low end torque (i pull heavy trailers) and mpg. The trucks I own are listed below.

2008 Ford F-250 Powerstroke (Automatic)
2008 Dodge Dually Cummins 6.7 (Automatic)
2003 Dodge Dually Cummins 5.9 (6 Speed Manual)
2002 Dodge Dually Cummins 5.9 (6 Speed Manual)
2001 Dodge Dually Cummins 5.9 (6 Speed Manual)
2001 Dodge Dually Cummins 5.9 (Automatic)


If I had to choose 1 truck for commercial use, it would clearly be the 2003 cummins with the 6 speed manual transmission. Its got monsterous low end torque, more than any of the trucks I own... yes more than the 6.7, although the 6.7 and 5.9 (six speed) are about equal at 65mph pulling over 20klbs. Another reason is the mpg's, I live in San Antoni TX and pulled daily loads to Edinburg TX (which is an 8 hour round trip) and could get away with roughly $120 in the 5.9 vs about $200 in the 6.7, I must say doing this every day, I clearly used the 5.9 for the long hauls. The only advantage that I like on the 6.7 is the exhaust brake and usability of the automatic six speed tranny in town. As for the other trucks The 2002(5.9 six speed manual) still has more low end torque than any automatic truck and holds its own on highway speeds. The 2001(5.9 five speed manual) has excellent low end torque but cannot perform as well on highway speeds. The 2001 (5.9 automatic) is not a very good work truck does not have much low end torque nor does it do good on the highway, although it is extremely reliable....as are all of my dodge cummins trucks... The new 2008 F-250 does not have the torque I expected but does very well once on the highway... but is the biggest gas guzzler of them all.. I hope I've answered any questions that anyone might have. Again to reiterate I have been in business since 2001, hence why I own older trucks... I pull very heavy gooseneck trialers with wood pallets....So I speak element and truth about these trucks. Please feel free to contact me if you'd like a suggestion on what type of truck to choose.
 

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Fuel Consumption on a 6.7

I've got a 2008 3500 4x4 dualy, pulling a 39 foot 5th wheel trailer. The trailer weighs about 12,000 lbs. I just dragged this thing to south dakota and my fuel milage change dramaticly along the way. Throught CT, NY, and PA I was getting about 9.8 mpg. once passed OH it dropped to 8.5 mpg as I got throught IA and SD it dropped to 7 mpg. The situation revesed itself on the way back. as I got closer to CT the fuel mpg increased back to 9.8. Any ideas?

Personaly I love the truck but the fuel economy is horible. The truck has about 7,000 miles on it.
 

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I've got a 2008 3500 4x4 dualy, pulling a 39 foot 5th wheel trailer. The trailer weighs about 12,000 lbs. I just dragged this thing to south dakota and my fuel milage change dramaticly along the way. Throught CT, NY, and PA I was getting about 9.8 mpg. once passed OH it dropped to 8.5 mpg as I got throught IA and SD it dropped to 7 mpg. The situation revesed itself on the way back. as I got closer to CT the fuel mpg increased back to 9.8. Any ideas?

Personaly I love the truck but the fuel economy is horible. The truck has about 7,000 miles on it.

Most likely you had a very steady incline while traveling there and on the way back you were traveling down hill. Though as I mentioned in my previous post my 6.7 is a diesel guzzler, just simply because the displacement is larger than the 5.9 liter.... everything about it is bigger bore/stroke...therefore consuming more diesel..there is really no way around it. Great truck ,just not very fuel efficient.
 

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Although he likes the truck, he said he would not buy another one. Next time he'll buy a gas engine.
Sometimes the older you get, the lower your testosterone levels are. Sounds like that's the case here.

I suppose the 5.9's might be a little better MPG wise.
 

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My 6.7 has the cold air intake, emmissions removed and the smarty, mpg's are awesome compared to the same truck but stock. The 6.7 stock is a waste realy, you unleash the beast when you do the mods. My mpg's stock were anywhere from 13 to 16 highway mpg's. Now, anywhere from 20 to 24.5 highway mpg's, almost 10 mpg's improvement. I love my 6.7 now, wouldn't trade it for any other rig.
 

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I just picked up my 2007 dodge ram 3500 slt sport 4x4. Driving it here from Dallas I was getting anywhere from 16-18 on the highway with all the trash emissions installed. Its got 61k on the clock. Once my factory warranty is up I'm taking all the emissions off.

Once those are off I think this is a really efficient motor. I mean even with all the emissions on it, its an 8000 lb truck with an automatic and 4x4 and I'm able to get 18 mpg highway? and about 16 in town...thats the same as my trailblazer with its little 4.2 gas inline 6.
 
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