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Discussion Starter #1
Ok , I did a nice compilation of 2 different mpg over a month period and the results are always the same(by hand) . Same highway, same distance, and+or- same weather. And the trucking rule I`ve learn over time looks like to be the same with the 6.7. First, 1950rpm(+-65mph) gives me 18.7 to 19.2 mpg and secondo, 2200rpm(+-72mph) is 14.7 to 16.2mpg. Results are always the same over a month. The 18 wheeler rule we use is from 55mph every 5mph faster is 10% more fuel+-. The test is done on a 07 6.7 manual quad 4X4 long bed. So.....slow down I guess :sly: Sorry I always use rpm as a reference....trucker`s way to do it!
 

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I've tested mine over the past 2 months in the same conditions as yours. I have a 6.7 2007.5 4x4 quad short bed with manual 6. I run the same 1950rpm at 65mph and get 20-22mpg. when I go any higher than 65 I slowly loose mpg. At 70mph 18mpg is the max, and at 75 I get 16. If I go 60mph i still get the 19-20 mpg but nothing over. I don't do any of mine by hand though, just goin by the overhead. The numbers are always consistent though. weather is consistent too. little to no wind mind you.
 

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The auto with 3:73 @ 1950 RPM is 72+...I think? Mileage at that speed/rpm is not very good for the autos. I wonder if it has something to do with resistance at 70+ mph?
 

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Discussion Starter #4
Rich said:
The auto with 3:73 @ 1950 RPM is 72+...I think? Mileage at that speed/rpm is not very good for the autos. I wonder if it has something to do with resistance at 70+ mph?

probaly resistance for sure, and the rpm at 65 must real low on the auto?
 

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Discussion Starter #5
Fat Kid said:
I've tested mine over the past 2 months in the same conditions as yours. I have a 6.7 2007.5 4x4 quad short bed with manual 6. I run the same 1950rpm at 65mph and get 20-22mpg. when I go any higher than 65 I slowly loose mpg. At 70mph 18mpg is the max, and at 75 I get 16. If I go 60mph i still get the 19-20 mpg but nothing over. I don't do any of mine by hand though, just goin by the overhead. The numbers are always consistent though. weather is consistent too. little to no wind mind you.

Wow, that nice, any delete kit and how many miles on your truck?
 

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No mods as of yet. Just rolling over 17600. I'm waiting to see if there is any other problems or flashes. I'm waiting to hear back from H&S to see if it really matters if I dont have the edge w/ att in order to run the delete, and if there aren't any problems then I will be getting the kit. Then I will be looking to get an S&B intake not long after. If I have to run the edge then I will wait alot longer till I get the delete. That good ole warranty!
 

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hey fat kid you do know dpf delete voids warrenty also. probably more so than the edge. dealer showed me where and how to plug edge in. also how to unplug. lol. maybe you do know, but the way i just read it you won't do the delete if you need edge because of warrenty issues. anyway i don't really think you have to have edge juice, but it is the only programmer to clear codes automatically before startup. insight will clear codes, but manually. waiting for code free dpf delete is what i think i'm going to do. it sucks, but should be worth the wait.
 

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Discussion Starter #9
Thanks I always like to know these things :Thumbup:
 

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From Rich "70 = 1700 ish RPM and 1900 = 75 on my auto"
I have a 3:73 rear 2008 CTD MegaCab and it's getting his numbers also for it's 1st 509 miles. Was expecting better than 15.8mpg hand calc though with the overhead showing 18-20 almost as a constant.
 

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Were those numbers "in town" or on the Highway? My avg in town is low. I drove to the lake...50 miles Innerstate and 35 miles of back roads...one traffic light and back home = 13.2 on the overhead. I have yet to put fuel in the truck but I doubt I'm getting 13. The overhead is off by, at least, 1 MPG...and not to my favor.

....Then again, it could be the codes? I had the "Big Flash" done last week and by Sunday the CHECK Engine light was on. The dealer replaced my 02 sensor yesterday.

edit: Sorry about the rant. I forgot this was for the Hand-Shaker 6-speeds.
 

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Discussion Starter #12
I don`t think we can really trust the overhead in town. Usualy it works great on highways while driving at a steady speeds and by resetting the overhead at the same time. All my hand calculated mpg don`t match the overhead for city driving but they do for highway driving
 

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I have been thinking about a overdrive unit behind my 6spd manual. I think that getting the RPM low on these 6.7s would help the fuel mileage.
 

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Discussion Starter #14
SK-Buckwheat said:
I have been thinking about a overdrive unit behind my 6spd manual. I think that getting the RPM low on these 6.7s would help the fuel mileage.

probably a good idea at speeds around 65mph, but like tractor trailers the worst enemy is windshield ! If too low rpm at 70-80mph it will be worst!
 

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I think engine load vs. RPM..... You might be surprised how slightly higher RPM can net better fuel mileage.
 

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Discussion Starter #16
Rich said:
I think engine load vs. RPM..... You might be surprised how slightly higher RPM can net better fuel mileage.

That`s for sure, I don`t think low rpm means more mpg.
 

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mpg

truck avg 15-16 over head disp always shows 17-18 mpg.best so far 18.5 over head said 20 mpg that was avg speed 70 mph anything over made it lower mpg. hopefully dpf delete will help @ $4.29 pg and going up:damnit




2007 2500 Q-cab L-B 4x4 MBRP exhast S&B stage 2 air intake 6.7 CTD 6 speed man.:woot:
 

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Discussion Starter #18
Taking off that DPF will make a big difference.That engine is choking big time, have a look at your stock air filter compare to the 5.9.....WOW! half a foot thick!!! 6.7 is choking on the way in and on the way out!!!
 

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Sure would be nice if we could get a filter test going like one of the other boards did some years ago.
 

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mine after the recalls and several differant flashes is getting 623 miles to a tank taking 33.7 gallons.(mostly interstate 68ish mph) i've had the overhead read 27.2 for a high. flat level road 6 gear at 45 mph 1350ish rpm's that driving was combined with a heavily loaded truck for about equal driving distances 525 miles 33 gallons. heavily loaded back country roads mostly 4th 1500-1700 rpm's and gentle around town driving 505 miles 33 gallons. the overhead consistantly reads high. i had 80 miles to empty rapidly accelerated the over head went to 68 miles before i hit 5th gear, then after easing into a steady 1600 rpm's it then read 85 miles to empty. on an older lincoln the dash calculator is right on. 18 gallon tank ran it on fumes it read 12 miles to empty the car took 17.6 gallons guages read 21 mpg and i had put 361 miles on that tank.(not trying to milk the tank dry)
 
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