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6.7 L Fuel economy

204K views 104 replies 67 participants last post by  Jimmy N. 
#1 ·
I'm looking for some feedback on what type of fuel economy 6.7L owners are getting. Real world type of info, not dealer or manufacturer "suggested" efficiencies. Any info would be greatly appreciated. I presently own an 05' 5.9L and get in the high teens, and logic tells me bigger engine, less mileage. Thanks! Muck Aloha...
 
#2 ·
Lie-O-meter in the dash is telling me 8mpg bombing around the city. Still on the first tank though. LOL
 
#4 ·
I have an auto, 3.73 gears and the stock 31 inch tires. With 5000 miles on the odometer the dash is showing 15 to 16.4 MPG on the highway. This is unload and completely stock.
 
#5 ·
I was getting 12mpg in town and around 17 highway, post deletes I get 15-16mpg in town and 20 highway.
 
#6 ·
3500, crew cab, srw, 3.73, auto, no deletes. First tank I calculated at 12.9.

Certainly 1 fillup is not enough to get a good idea, but that fillup told me the computer was 1 mpg optimistic. Its probably more of a percentage than just 1 mpg, like my car which consistantly reads out 8% better than actual
 
#10 · (Edited)
Stock from the dealer I was able to get 13mpg city/hwy (after trading in my 5.9 that got 22HWY mpg's) :doh:
then I put on 35's and a 2 inch leveling kit and I averaged 10mpg HWY with just about 600lbs of tools on a 700 mile trip only stopping for fuel. :banghead::banghead:

SO..my dpf fell off today :shock:(thanks MPF!) and i will make the same 700 mile trip tomorrow.

but I can tell you from a 40 mile trip cruise set at 55 the EVIC showed me 25.5 mpg :shock: NO ONE here is gonna believe that's an accurate number, and I'm sure it's not
LOL :rof
That was yesterday with only the EGR deleted, now that the DPF is gone I've just been heavy throttle on mild around town, and its showin 16mpg :party018:

SO tomorrow i'll do the math on a couple tanks of fuel and report back!

but I'm aimin for 20 :thumbsup:

truck sounds BAD ***, got a little bit of drone around 2.1k might just annoy the hell outa me hehe :p
 
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#11 ·
About 80MPG on a blend of Unicorn piss and Dino jizz ;)

Seriously I get between 20-20.8 HWY and 15-16 in town if I keep my foot out of it, on 35x12.50x20's but it's pretty flat where I live also. 10.8 with a LOADED 40' gooseneck at 75 on the interstate
 
#16 ·
I've got the dino jizz, but where the hell can I pick up unicorn piss? Think autozone would carry it?!?
 
#12 · (Edited)
When it was stock 14/16. With mods in my signature 18/21. Towing fifth wheel 12-13.8
 

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#14 ·
Last all highway trip @ the speed limit or 5 over 19mpg. Highway between 70-80 the whole way 16.8. Around town 14-15.5 depending on what I am doing. The above 19mpg trip was with 3 dudes in the truck each pushing 230 and a bed full of gear for 2 weeks.
 
#17 ·
I see around 14.7-15.5 half city half hiway back and forth to work. 2012 mega cab 3.73's and 35's auto trans. Undeleted for now
 
#18 ·
On the 2 lane highway going 50-55mph I get 19mpg, on the 4 lane at 63mph and get around 18. On the interstate running 78mph I get 16.5+mpg. I have 285/70/17 tires so that works out to around 32.5-33in and 373 gears. I just pulled an empty trailer at around 60mph for 40miles and then drove though town for a few miles. Empty it weights around 3500lbs I got 13mpg.

Cory
 
#20 ·
2011 3500 srw 3.73 G56 stock tires

Stock: 14ish town/hwy, 17-18 doing 60-65, 16-17 on the interstate
Towing: 3 horse slant trailer with full tack, 10.5mpg

Deleted H&S on mild:17ish town/hwy, 21-22 if i run 55-60, around 20-20.5 @ 65
Towing same trailer 12.5mpg on "no power level"
This is driving nice and easy
 
#21 ·
update:
780 mile trip from WA to UT,
quite a few long steep grades along the way, my EVIC is very very close, reading 18.8, I did the math and came up with 19.2. the money I saved on this trip pays for the egr delete. And I've fallen inlove all over again ;)

I was driving normally, half the trip was driven at 65-70mpg and the other half at 75-80.
 
#22 ·
2008 1/2 3500 dually quad cab, LB, manual with 16 ft bumper pull utility trailer. 20.5 plus running 60-65 mph. Very carefull driving. Go through regen about every 300 miles. Hand calculation beats lie o meter slightly. Believe way load trailer helps milage.
 
#24 · (Edited)
2011 HO 3.73's, 4wd w/35's with 15,000 on it. I have never hand calculated but occording to the lie-o-meter I have never averaged over 14.5 or so on a trip over 100 miles....even if I'm easy on it. Usually average around 12.5 to 13 mixed driving. I have towed my boat (19 ft Carolina skiff ultra) to the coast about 4 times with it and usually average about 8.5 to 9.5 mpg over the 300 mile round trip. I do drive the speed limit or a little above on the hwy most of the time though...
 
#25 ·
2010, 77K, H&S mini max on no power and DPF delete pipe running from Niagara Falls to CT last week keeping the MPH under 75 running cruise set at 70 most of the time I was getting 20mpg. I live 62 miles away from work and only have to go in every third day so a tank lasts me 2 weeks. That highway coupled with the back and forth town driving for errands and kids sports I average anywhere between 17-18.4. If I drive responsibly I can keep it in the 18's if I avoid the hills but if I'm running it with eb on and playing with it to listen to her it'll drop to the 17's.

With that said I never hot dog my truck or hammer down. I've never spun the tires or run it full throttle and never had the MM above no power. Too afraid of the weak links in the drive train now that I'm deleted.

Just my .02 take it for what it's worth
 
#29 ·
your pushing 850 ft lbs of torque and you have never spun your tires!??
you have never took your 1000$ programmer past stock settings!?!???
:omg:

..i'm pretty sure I spun the tires on the test drive... xD
 
#26 ·
2012 3500 CC LB ... Truck has about a 1000 miles and she is bone stock. My last trip to Atlantic city and back to LI which is about 350 miles I averaged high 14s.

Hoping to delete sometime in the future... 20mpg here I come... :)
 
#27 ·
All stock, nothing deleted. I get 18.6 on the highway. In rural areas, about 16. Less in town. I have a CC LB, 6 speed manual and 3.42 axle ratio. (I ordered this combo for peak mileage, I wont tow over 5000 lbs, but can still tow almost 13,000) I will delete when its closer to 5 yrs old and should get over 20. If i reset it and run highway, i will get over 20 if I dont have a regen.
 
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