# Happy With My Diesel Mileage



## N7OQ (Jun 10, 2006)

Well I did a trip to Lake Tahoe last weekend then drove my truck in town for a week and still had a 1/4 tank of diesel when I filled it up today and found out I was getting almost 18 mpg, actually 17.88mpg. This is without towing my trailer but I did have a loaded bed with everything for a 60th wedding anniversary for my parents and we was driving in the mountains and I was in no way trying to get good millage, I was having fun going up the grades passing everything on the road. I don't even have 2000 mines on the truck so millage should get better when I get some millage on it. I really think I will get over 20 mpg in a long trip without lots of mountains and using cruse control. The only time I checked it with the Trailer behind it I got a little over 14 mpg and that was towing in the mountains too.

So far I really love this truck and really need to use it more, it is so cool to get good millage and have power too.


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## mountainlady56 (Feb 13, 2006)

I loved my diesel (Dodge) and the ability to relax and enjoy the ride, instead of fighting a 1500 gasser to make it up the hills. I pulled a 27RSDS and a 31RQS (separately, of course), and had plenty of power and then some. I, too, was happy with the diesel mileage. I found that if I kept the RPMs at 2K or less, it definitely kept the mileage better. Usually, I drove around 62 MPH, towing. I got around 18 MPG without the trailer and around 12-13 MPG towing.
Enjoy!
Darlene


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## raynardo (Jun 8, 2007)

How did you computer that incredible mileage? Did you use the on-board computer mileage computer? Or did you use a calculator?

I've never gotten that kind of mileage even when I don't tow our trailer!


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## SouthLa26RS (Jul 10, 2006)

That is good mileage. My 08' gets 10.5 while towing on flat terrain. Unloaded I am averaging 15.8. I do not have a heavy foot and the truck has no performance mods. Have 13,500 miles on it now.


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## nynethead (Sep 23, 2005)

my chevy gets 20 on the highway (doing 75) no trailer, 17 all around driving and 12+ towing depending the grade and speed.

I now have 44K and i still do not think it has broken in yet. I use AMS synthetic oil and the engines not wearing.


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## tdvffjohn (Mar 10, 2005)

Towing the fiver, I average about 12, without any trailer cruising 65- 75, I get 18-19 and thats with a duelly!


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## GarethsDad (Apr 4, 2007)

raynardo said:


> How did you computer that incredible mileage? Did you use the on-board computer mileage computer? Or did you use a calculator?
> 
> I've never gotten that kind of mileage even when I don't tow our trailer!


That would be because you have Fords/IH worst diesel engine the dreaded 6.0l. I had a (04 F350 4x4 ecsb)at work that dumped the coolant into the heads locking up the engine. It was replaced with a 06 and the milage is worse (13 not towing) than the 09 duelly dump truck with the new 6.4l (12 towing). Trailer towed is a 25' flat bed equipment with a 9300lb mini excavator. James


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## folsom_five (Jan 10, 2008)

That is great milage that you are getting!
I am getting nowhere close to you with my 6.0L Excursion, but I sure do love the power. 
So far on our cross-country trip the truck computer is saying I am averaging about 10.6 mpg. I have not hand calculated it yet, so not sure how accurate that is.


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## Nathan (Jan 2, 2007)

I'm shocked by those numbers if hand calculated. Most diesels with DPF's get worse fuel economy than that. It will be very interesting to see what the next level of emission controls will do to fuel economy.


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## raynardo (Jun 8, 2007)

folsom_five said:


> That is great milage that you are getting!
> I am getting nowhere close to you with my 6.0L Excursion, but I sure do love the power.
> So far on our cross-country trip the truck computer is saying I am averaging about 10.6 mpg. I have not hand calculated it yet, so not sure how accurate that is.


Pulling our trailer with our truck, I have been averaging 11.2 mpg over the truck's first 31,000 miles. I use the truck almost exclusively for pulling my trailer.

In ten days we'll be leaving on a 7000 mile 3 week vacation, driving from Southern California to Lake Superior in Wisconsin, over to Yellowstone (where my wife and I met 40 years ago this summer - we were both working there), hopefully Glacier NP, then the Sandpoint, Idaho area, and then back home. I religiously keep a spreadsheet of the fuel consumption, including the number of hours the truck has been running, so that I can correlate the fuel economy with the average speed. since day one. And I will do so on this trip as well.

I don't want to get into any flame wars regarding truck loyalty, but I should note that I've had excellent luck with my truck. I was fortunate enough to buy a truck that would run the old style diesel fuel, and since I'm so close to Mexico, a consideration of mine, since I believe Mexico has not implemented the ultra low sulfur diesel 100%.

I'm always in awe of those folks that get these fantastic fuel mileages pulling 8000+ pounds of trailer. I lock in my cruise control at 62 mph, and my truck goes straight, up mountains, down mountains and always at 62 mph. Downhill I get passed by all the folks I passed when I was going uphill.


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## swanny (Oct 31, 2007)

07 gmc 2500, pulled 38' fiver, kept it between 60 / 65 mph, 1375 miles and got 12.5mpg.


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## Carey (Mar 6, 2012)

Nathan said:


> I'm shocked by those numbers if hand calculated. Most diesels with DPF's get worse fuel economy than that. It will be very interesting to see what the next level of emission controls will do to fuel economy.


I think the next generation will be back to similiar reliability of the pre egr trucks if the Urea is used..

I know in trucking that many are expecting, that looking back, the egr/dpf semi trucks will be a piece of junk comparred to using Urea technolgy.. In trucking the egr systems will be much less complicated when using Urea.. I Know most trucking companies cannot wait for Urea...

Who knows what the next light trucks will bring in reliability using Urea.. I cant wait to see..

Thats about avg for your truck Bill... The new chev dually guys in our fleet are getting 15hwy and 10-11 loaded hand calculated.. But there trucks weigh over 10000lbs empty.

If I run like you did, I get the same 17-18 wth my empty 10000lb dually.. I just took a lil 4500lb trailer to Canada and got 13.3 at 63mph.. Not bad considering I was still grossing a good 15000lbs..

I dont think youll ever see 20, but 18 for a chev dpf 3/4 ton is prolly a reality..

Carey


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## Husker92 (Feb 11, 2006)

Last year from California to Mount Rushmore and back about 3000 miles, I averaged 12.5 mpg in our F250 diesel.

Happy Outbacking!


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## FlashG (Jun 23, 2007)

I get 20 mpg on the freeway without a trailer and around 12 mpg with my former 5er. The mpg's went up after 5000 miles.


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## N7OQ (Jun 10, 2006)

raynardo said:


> How did you computer that incredible mileage? Did you use the on-board computer mileage computer? Or did you use a calculator?
> 
> I've never gotten that kind of mileage even when I don't tow our trailer!


I did it the old fashion way, filled up drove and filled up again at the same pump and divided the miles drives by the diesel used. I don't have a 4x4 so that might help some.


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## N7OQ (Jun 10, 2006)

Well from what I see the Duramax's seem to do well in the millage area and I'm very happy that I'm getting as good of millage as I'm getting. From what I read it is not unusal for a empty truck to get 20+ MPG so no matter what dirtbike says I do believe I will get 20+ on the flat road. As usual C-dirtbike has to chime in and point out how my truck is a piece of junk in his usual roundabout way, and I know that by making my







comment here, he will write a book about why my truck is piece of junk.


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## weekendwarrior (Jul 24, 2007)

Just came back from a trip to s. cal averaged about 15 on the way down and 13.5 on the way back my duramax used to get about 20 mpg without towing until i lifted it. Now about 16 and thats with the bully dog programmer.


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## Nathan (Jan 2, 2007)

Bill,

No one insulted your truck! I'd love to have that fuel economy. Traditionally, the order for fuel economy has been Cummins, Duramax, and International. (Noticed I listed engine brands rather than truck brands since 2 of the 3 are purchased and the 3rd was heavily influenced by Isuzu.)









Sure, there are variables including 2WD/4WD, ride height, emission levels of the truck, aftermarket mods, driver, etc.
It all factors in and that's why even on a car they give you a fairly wide mileage range to expect. Heck, if you manage to get 20mpg on the flat highway, I think that is great!

_*Now, allow me to Hijack and step up on my soapbox:*

Anyone with a 3/4 or 1 ton truck has plunked down a considerable chunk of cash to drive that vehicle. This makes it difficult to deal with when someone either directly or indirectly implies that their personal choice was better than yours. I freely admit that I only had 1 brand to choose when I purchased, however those of us with ties to the industy have a more unique situation. The flip side of that is that we carefully dissect and study all of the trucks to compare what each competitor is doing. To do this correctly, you must get beyond the emotions and focus on the data and analysis of each part. I wish we all could step back from brand loyalty and look at each truck for it's merits. Then we could all say we picked the truck that best fit our needs.

Perhaps in the future, someone will come out with the best vehicle that has the best powertrain, the best payload, the best interior comfort and then we can all buy the same truck. Alas, as all of our needs are different, perhaps it's better that we have the choices and then try our best to look objectively at the data, pick the best truck for us, and then not look back or get jealous or defensive if someone made a different choice.

*Ok, exit soap box*_

Everyone have a great day!


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## Collinsfam_WY (Nov 9, 2006)

N7OQ said:


> Well from what I see the Duramax's seem to do well in the millage area and I'm very happy that I'm getting as good of millage as I'm getting. From what I read it is not unusal for a empty truck to get 20+ MPG so no matter what dirtbike says I do believe I will get 20+ on the flat road. As usual C-dirtbike has to chime in and point out how my truck is a piece of junk in his usual roundabout way, and I know that by making my
> 
> 
> 
> ...


I have no idea how someone could look at the contents of Carey's post and end up typing the response above.







I got no indication whatsoever that he thinks "your truck" is a piece of junk. Nor have I read any post anywhere (by him) that would indicate he thinks chevy duramaxes are pieces of junk. I have however read a wealth of information that he has typed on weaknesses of every brand of truck that is in the fleet he pulls for. In fact, I would say that he tends to list the shortcomings (for someone who uses a truck in his line of business) of his Dodge more than any other truck - by far.

In fact, I would say that considering the experience he has, he goes to substantial lengths to be fair in his commentary.

-CC


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## N7OQ (Jun 10, 2006)

collinsfam_tx said:


> Well from what I see the Duramax's seem to do well in the millage area and I'm very happy that I'm getting as good of millage as I'm getting. From what I read it is not unusal for a empty truck to get 20+ MPG so no matter what dirtbike says I do believe I will get 20+ on the flat road. As usual C-dirtbike has to chime in and point out how my truck is a piece of junk in his usual roundabout way, and I know that by making my
> 
> 
> 
> ...


I have no idea how someone could look at the contents of Carey's post and end up typing the response above.







I got no indication whatsoever that he thinks "your truck" is a piece of junk. Nor have I read any post anywhere (by him) that would indicate he thinks chevy duramaxes are pieces of junk. I have however read a wealth of information that he has typed on weaknesses of every brand of truck that is in the fleet he pulls for. In fact, I would say that he tends to list the shortcomings (for someone who uses a truck in his line of business) of his Dodge more than any other truck - by far.

In fact, I would say that considering the experience he has, he goes to substantial lengths to be fair in his commentary.

-CC
[/quote]

Well you are correct, I just over reacted, I was very stressed that day and should not have even posted a thing I was in the wrong mood. Sorry Carry I take it all back.


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## Carey (Mar 6, 2012)

Eh, no biggie Bill...

Carey


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## matty1 (Mar 7, 2005)

yeah..lets stop bashing the gassers... I love chanting "I think I can...I think I can.." on every hill


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## rock hill (Apr 17, 2009)

yeah, we all need to settle down, at least we can all agree on one thing Outbacks are awesome!!

and ford stinks. ( I can say that because I tow with one, and the stinking thing thinks the door is ajar when they are not, plus the AC is giving us problems. and I want a diesel )


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## Nathan (Jan 2, 2007)

rock hill said:


> yeah, we all need to settle down, at least we can all agree on one thing Outbacks are awesome!!
> 
> and ford stinks. ( I can say that because I tow with one, and the stinking thing thinks the door is ajar when they are not, plus the AC is giving us problems. and I want a diesel )


no one listens ...


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## Calvin&Hobbes (May 24, 2006)

Nathan said:


> Bill,
> 
> No one insulted your truck! I'd love to have that fuel economy. Traditionally, the order for fuel economy has been Cummins, Duramax, and International. (Noticed I listed engine brands rather than truck brands since 2 of the 3 are purchased and the 3rd was heavily influenced by Isuzu.)
> 
> ...


Very well put!


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## beachbum (Nov 27, 2006)

My 07 Classic with the LBZ WAS getting pretty decent mileage 'til I bought new tires.







I went from stock 245's to 265's, an increase of just over 1" circumference. (16" wheels stock..look soooo small on that truck!!).







Bought a programmer to make the odometer and speedometer correct.







Mileage around town went to 16-17mpg. Toeing went to maybe 11mpg if I was lucky.














RPM's towing are still just below 1500, but the mpg is just poor!!! Tried driving 55mph to see if tha made a difference. MPG got worse.







It seemed to be better at about 65-70, motor just above 1500rpm.







Can't wait to wear these BFG A/T's out so I can get back to stock!!







What a waste of good money (or the money used to be good!!).







Truck just went over 50K and I'm using only for towing now, so my hope/wish /dream is that after break in, mileage will go back to the 14-15 I was getting with the stock tires.







Driving, I run the numbers in my head.....let's see, 2-3mpg less, 26gal tank, could go 70 miles further at 2.50 per gal equals $10.00 more per tank and 30 minutes more because of the extra stop, etc,etc, etc.







Right now, I am making 200 miles runs at 60 miles per hours, stop every 3 hours when i could be going 260 miles, stopping every 4 hours.........well, you all know how it goes, I'm sure.








Anyway, if you change the ties size, you're gonna screw things up!!!








david


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## Carey (Mar 6, 2012)

1500 is a bad rpm for towing on any small diesel.. The engine is designed to be more efficent at a higher rpm.. You could be getting some poor burn conditions, which creates clogged egr's, high oil soot, and cylinder wear from high amounts of unburned fuel and particulates.. Also more heat is generated running under peak torque.

Your engine makes peak torque at 1600 or so.. The sweet spot of your engine is just above peak torque.

Id get those tires off asap or run at a higher rpm..

Carey


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## beachbum (Nov 27, 2006)

I don't think the boss will let me drive 75-80mph. that would be my speed at about 1600-1700rpm. Let's see, other options would be.....
drive in 4th-5th gear, don't use "tow" mode. Keep only 30lbs of air in tires ...
So it's not my imagination, engine is more efficient at higher RPM's. We've already made 2 FL tips with these tires (about 4K miles). Be my luck that these tires will probably last forever...
david


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## Carey (Mar 6, 2012)

beachbum said:


> I don't think the boss will let me drive 75-80mph. that would be my speed at about 1600-1700rpm. Let's see, other options would be.....
> drive in 4th-5th gear, don't use "tow" mode. Keep only 30lbs of air in tires ...
> So it's not my imagination, engine is more efficient at higher RPM's. We've already made 2 FL tips with these tires (about 4K miles). Be my luck that these tires will probably last forever...
> david


Seriously.. You need to keep that engine above 1600 at cruise if towing if you want it to last... Whatever you gotta do, do it..

Its not the tires, that is the mpg problem... Its the rpms..

Staying in the diesel engines sweet spot is much more important than a gas engine.. Semis are no different..

The engine is engineered to run where the factory put it to run.. Mucking with that will only cost you in the end..

I would wager that if you get those rpms up, your mpg will go right back up too..

Carey


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## beachbum (Nov 27, 2006)

Thanks Carey, for the info, I know you know your stuff. Seriously, From the long trips we've been on, I know I can get the rpm's up and still be OK speed wise.
I did have the sense the engine was just "loafing" along at 14-1500 rpms, not really running. (if that makes sense). Transmission seems OK, doesn't "search" and does not get hot.
Last but not least, I get oil analyzed by Blackstone Lab at each oil change. So far, none of the bad things you mentioned are showing up. Engine is going about 9K between oil changes, with no problems. I'll keep an eye on this!!
david


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## Carey (Mar 6, 2012)

beachbum said:


> Thanks Carey, for the info, I know you know your stuff. Seriously, From the long trips we've been on, I know I can get the rpm's up and still be OK speed wise.
> I did have the sense the engine was just "loafing" along at 14-1500 rpms, not really running. (if that makes sense). Transmission seems OK, doesn't "search" and does not get hot.
> Last but not least, I get oil analyzed by Blackstone Lab at each oil change. So far, none of the bad things you mentioned are showing up. Engine is going about 9K between oil changes, with no problems. I'll keep an eye on this!!
> david


 Bring it out west and run it at 1500 towing and see what the OA report says.. If that engine is lugged much the OA will show it right up..

Prolly fine in the east, but try getting those rpms up and see if mpg improves next trip, just for fun..

Let us know!

Carey


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