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Cummins 6.7 fuel milage

13K views 27 replies 16 participants last post by  88yj 
#1 ·
Anybody have the new 6.7 cummins? I'm looking at one 3500 long bed, crew cab 4x4, 3:73 gears, six speed auto. The dealer says I should get 20 mpg I believe that with the 5.9 but want to know if thats possible with the 6.7.
 
#2 ·
My old '92 Dodge 1 ton non-dually auto 3.73 would get 19 mpg all the time with 240,000 miles on it. I don't see why the new technology couldn't get 20 mpg, even with a bigger engine. I know it has to be way more effiecent than mine was. The '92 wasn't even computer controlled and the turbo was so sad it was without a wastegate.

I too would like to hear from someone who actually ownes a 6.7 how it does on the fuel milage.
 
#5 ·
I can promise the 6.7 will get worse mpg. It's because of the particulate trap in the exhaust and how often that trap needs to be cleaned out by burning extra fuel. All new diesel trucks have this problem and it will only get worse in a few years.
 
#10 ·
I find it hard to believe that a 5.4 excursion got 14 mpg empty.

How fast were you towing? You got up to, like when you were coasting on the exit ramp the computer read an instant mpg of 14 mpg and an average of 6?

255 horspower and 7,000 + pounds, towing 5,000 pounds = piss poor mileage.
 
#9 ·
New 6.7 cummins suck for fuel mileage. My dad brought a 2wd dualie home a few weeks ago, got 15 going up north. :( And they are having lots of problems with them. If you can, I would try and find a 5.9.
 
#14 ·
unfortunately every time new "tech' goes into the cummins, mileage goes down. first gens still get the best mileage.
My 91.5 CTD gets 19-20 MPG and has the added ability of clouding up a whole parking lot warming up on a 10 degree day :sonicjay:
 
#15 ·
My Mother In-Law and her husband used my discount to buy a loaded down Larmine 3500 Dually with the 6.7L and they love it. This truck kicks ass, it has every option on it except a sunroof. They pull a very big 5th wheel and travel all over the U.S. He hasn't had any problem with it and they both love it. They just made the trip from CA back to MI and back down to FL. I'll have to give him a call tonight and ask him about mpg.
 
#21 ·
I just talked with my inlaws and they said they are getting 16 in the city w/o the 5th wheel and while towing it on the highway they have been getting around 17mpg.
 
#18 ·
bullshit.

05 CTD quad cab auto 4x4 short bed 3.73, overall mpg average is 15.89 over 56K miles which includes towing something about 1/4 of the time. Stock for most of the 56K. Recent mods are free wheeling hub kit and Smarty. Still never have gotten 20 mpg on any tank, even when empty with all highway miles. Typically between 18 to 19 mpg highway empty, 15 to 16 around town. Now if you’re a sucker and believe the overhead lie-o-meter, my truck gets like 21 mpg. I suspect many of the inflated MPG claims are from CTD owners that think the lie-o-meter is accurate :miff:

MPG from 6.7 owners: (does not look like they are any better than the 5.9)

http://www.turbodieselregister.com/forums/6-7l-engine-transmissions-2007-5/193247-6-7-mileage.html

http://www.turbodieselregister.com/...ansmissions-2007-5/193595-15-9-mpg-today.html

http://www.turbodieselregister.com/forums/6-7l-engine-transmissions-2007-5/193706-6-7-mpg-g30.html
 
#20 ·
I have had 4 CTDs the best was a 96 with 3.55 that could see 20 mpg if driven like a grandpaw and the worste was a 99 7" lift 37s 4.56s about 13 mpg. I have had 3 7.3 powerstrokes all get about 15 mpg all on 315s and 1 duramax got 18 mpg and pull jeeps and machinery all the time. I have never gotten better than 12 with anything towing. I currently have a 05 expedition 5.4 stock that gets 18 hwy and 12 towing a big TJ 75. I also have a leased ram 1500 hemi CC 4x4 that can get 20 empity AC off it has the deal that shuts off 4 cylinders, but towing my jeep to Canada last fall I got 8-9mpg. A friend at work has a 6.7 CC 4x4 auto that is not broke in and he gets around 16 and loves the power and trans. I have a friend on the fire dept that has a 05 that drives to detroit every day and is anal about calculating fuel mpg. with his flush cap he got 21 mpg, but with the new low sulfer diesel it went down to 19 and now when it is cold he is around 17. It seems if you want a big safe truck you will get around 16, you want it lifted you get 14 or less, you want better than that drive a honda, even better ride a spree.
 
#23 ·
And they determined this how? The overhead is wrong. Unless they are filling to the top of the tube, letting the air bleed out of the tank, and hand calculating, I don't believe it. My 5.9 gets 16 empty mixed highway/city. It gets 13-14 pulling my gooseneck car hauler, and about 11-12 pulling a 32' 5th wheel with a big profile front end...

Unless they drive 50mph and never leave Kansas.
 
#25 ·
My inlaws have the computer in it and that is pretty close. He fills up everytime and does the math himself and he said it's within .2 everytime. He doesn't drive it on the highway without the trailer but he said he would expect somewhere around 20mpg. I don't know if his truck has anything different on it but I would doubt it being that it's brand new and the sticker price was a little over $52,000. Off the subject but if you have ever seen the show on A&E "King of Cars" that is where he bought it.
 
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