I know there are some people who doubt that a CC, LB, DRW LBZ (my '07 GMC in my sig) can get anywhere close to 20 mpg, even some of my friends (mostly my friends who own 6.0/6.4 PowerStrokes) doubt me, but I finally had a camera with me when I made my monthly 820.8 mile trip up to Northern California. Attached is the photo of my dash after I filled up when I got home. This last trip, over the weekend, was actually my worst mileage of my last 5 trips. I think it was because the ambient temperature was consistently 105 degrees and my intake temp hovered around 110 degrees the entire time. My range has actually read 680+ during the Spring time when ambient temps were below 80 degrees, and I almost got 22 mpg. On this last trip, my DIC noted that I used 40.1 gallons of diesel, but I actually put in 38.17 - my DIC consistently records about 5% on the high side of fuel used. Even going by the DIC, my mileage is 20+ mpg. I just thought I would post some encouragement and help offer up some evidence to the other LBZ guys who get doubted about their 20+ mpg mileage claims.

The best I've ever gotten is 20.6 mpg with the truck in my sig.
Vin63, 20+ with a dually is sweet!

Thanks! I noticed that when the intake temp is above 100 degrees, my boost pressure is around 7 lbs to maintain 65 mph on level freeways, but when the intake temp is 80 degrees, or lower, my boost pressure is 4 lbs maintaining 65 mph - that's when I get the best freeway mileage. I think the lower oxygen content due to the higher temps makes a difference.

Here is a 40,000 + mile fuel mileage report. It should reduce the error of filling the tank. All tank fills are until pump cuts off no filling higher.

Best tank Cartersvill GA to West side of St Louis 542 miles on cruise 70 MPH 21.156 MPG

Total fuel mileage since truck was new 17.335 over 40,956 miles

Total fuel cost per mile $0.187

Mile per hour average for 40,956 miles 34.135

In the attached excel spreadsheet you can see the detail. Look for things like the mile per hour for a tank and note that if its low for congested driving then the fuel mileage suffers. If the MPH is higher than its better.

Note the error in the DCI. Its 3.720% since I started tracking this error.

My findings:
If i drive 50 MPH the fuel mileage on the DCI is 23 or 24 depending on season and outside temp.

If I drive 60 MPH then the MPG drops to 21-22.

If I drive 70 MPH then it drops to 18-19

If I drive 75 then it falls to 17-18

Around town on surface streets I have seen as low as 12 MPG In stop-and-go traffic at 25 MPH

Driving style/speed really impact MPG on this vehicle.

This is just my experience. Would love to see anyone else's experience that has documentation.

Here is a 40,000 + mile fuel mileage report. It should reduce the error of filling the tank. All tank fills are until pump cuts off no filling higher.

Best tank Cartersvill GA to West side of St Louis 542 miles on cruise 70 MPH 21.156 MPG

Total fuel mileage since truck was new 17.335 over 40,956 miles

Total fuel cost per mile $0.187

Mile per hour average for 40,956 miles 34.135

In the attached excel spreadsheet you can see the detail. Look for things like the mile per hour for a tank and note that if its low for congested driving then the fuel mileage suffers. If the MPH is higher than its better.

Note the error in the DCI. Its 3.720% since I started tracking this error.

My findings:
If i drive 50 MPH the fuel mileage on the DCI is 23 or 24 depending on season and outside temp.

If I drive 60 MPH then the MPG drops to 21-22.

If I drive 70 MPH then it drops to 18-19

If I drive 75 then it falls to 17-18

Around town on surface streets I have seen as low as 12 MPG In stop-and-go traffic at 25 MPH

Driving style/speed really impact MPG on this vehicle.

This is just my experience. Would love to see anyone else's experience that has documentation.

Wow, that's some dedication. I've been recording my mileage for the last few months, but only record engine hrs, miles, and trip from the truck :o:

The DIC does allow you to collect some very usefully information. When thats logged into a spreadsheet a story begins to unfold. you just have to read it and then decide what to do with the information.

The highest range I have seen was 500+, but I do have the 26 gallon tank.

Man that is sweet mileage with a dually!

It can be done, with my mods and PPE on the 350 horse tune i get 21-22 at around 65 mph No BS. These trucks are awesome!!

Here is a 40,000 + mile fuel mileage report. It should reduce the error of filling the tank. All tank fills are until pump cuts off no filling higher.

Best tank Cartersvill GA to West side of St Louis 542 miles on cruise 70 MPH 21.156 MPG

Total fuel mileage since truck was new 17.335 over 40,956 miles

Total fuel cost per mile $0.187

Mile per hour average for 40,956 miles 34.135

In the attached excel spreadsheet you can see the detail. Look for things like the mile per hour for a tank and note that if its low for congested driving then the fuel mileage suffers. If the MPH is higher than its better.

Note the error in the DCI. Its 3.720% since I started tracking this error.

My findings:
If i drive 50 MPH the fuel mileage on the DCI is 23 or 24 depending on season and outside temp.

If I drive 60 MPH then the MPG drops to 21-22.

If I drive 70 MPH then it drops to 18-19

If I drive 75 then it falls to 17-18

Around town on surface streets I have seen as low as 12 MPG In stop-and-go traffic at 25 MPH

Driving style/speed really impact MPG on this vehicle.

This is just my experience. Would love to see anyone else's experience that has documentation.

Yep, your numbers are accurate. That is exactly what I get.

Kansas buggy, I'm impressed, I thought I kept records but you put me to shame.

I pull trailers a lot but just for giggles and grins I went back and just pulled info when I'm was running single, I didn't see on your sheet where you pulled anything.

I've got a little over 116,000 miles on the truck and during the summer months I average 18.26, in the winter 16.99, she really likes spring and fall and I average 18.98 during those months.

The best mpg I ever got was 21.96. Unlevel ground at the filling station could contribute to that.

The worst I ever got was pulling my 5th wheel in a wind when the smart people were pulling over and stopping (I didn't say I was smart) was 7.31. They were actually stopping hi profile vehicles due to the wind, but they missed me.

My truck is a STOCK LLY and I hand figure everything and allow for some speedometer error. I figured the error out using a stopwatch, GPS and a ScanGauge II.

Here is a 40,000 + mile fuel mileage report. It should reduce the error of filling the tank. All tank fills are until pump cuts off no filling higher.

Best tank Cartersvill GA to West side of St Louis 542 miles on cruise 70 MPH 21.156 MPG

Total fuel mileage since truck was new 17.335 over 40,956 miles

Total fuel cost per mile $0.187

Mile per hour average for 40,956 miles 34.135

In the attached excel spreadsheet you can see the detail. Look for things like the mile per hour for a tank and note that if its low for congested driving then the fuel mileage suffers. If the MPH is higher than its better.

Note the error in the DCI. Its 3.720% since I started tracking this error.

My findings:
If i drive 50 MPH the fuel mileage on the DCI is 23 or 24 depending on season and outside temp.

If I drive 60 MPH then the MPG drops to 21-22.

If I drive 70 MPH then it drops to 18-19

If I drive 75 then it falls to 17-18

Around town on surface streets I have seen as low as 12 MPG In stop-and-go traffic at 25 MPH

Driving style/speed really impact MPG on this vehicle.

This is just my experience. Would love to see anyone else's experience that has documentation.

BTW,

Your spreadsheet is insane with detail. I like insane people.

The highest range I have seen was 500+, but I do have the 26 gallon tank.

Man that is sweet mileage with a dually!

I hear ya about the 26-gallon tank. If I can keep the wife's C2500HD CC, SB LBZ (in the sig) at 65 mph, or less, I can squeak out 22.4 mpg (hand-calculated) - bone stock and all unloaded freeway miles, of course. The highest range I've seen on our C2500HD was 563 miles after we took it for one of the 800 mile trips up North. The biggest and most difficult thing is keeping the velocity down.

I know most will call BS on this. But on a trip from Little Rock, Ar to Memphis, TN I got 24.67 MPG out of the truck in my sig. My DIC said i was gettin 23.4, so i decided to fill up when i got there to check MPG even though i was only at half a tank. Now granted i was doin around 60 or so(in a 70 mph zone) "drafting" behind 18 wheeler. I followed the same truck all the way there! haha. I got a picture of my DIC on my phone ill have to upload it.

I posted in RV.net once, my MPG after a trip and a few people basically called me a liar..

I did about 800 miles and I got 19, 19. something and just over 20 on the fill ups... That is hand calculated and the tank filled to the brim.......

Seems hit and miss with the d-max, the mpg really seem to vary..

It can be done, with my mods and PPE on the 350 horse tune i get 21-22 at around 65 mph No BS. These trucks are awesome!!


I agree !

I just did a roadtrip from central NC to Erie, PA and back and got 23.5 mpg with my current mods in my sig.

Last week I drove from Eastern NC to Ohio through WV, Cruise set at 70-75 though the mountains with a harley in the bed I got 20.44 MPG. I had to down shift a couple times goin up the passes to keep my EGT's below 1250*. On the return trip the cruise was at a steady 76 mph though the mountains and I got 19.44 MPG... I really pushed that tank till it was gone b/c WV prices where 4.69 and I saw a sign for a station in VA at 4.15 :D After the mountains I kept the cruise at 70 an d was lucky enough to not have to stop but 2 or 3 times and I got 22.3 mpg. The way to ohio was on my own custom mileage tune, and the way back was on the McRat race tune.

Now I'm headed from Eastern NC to Biloxi, MS and this time I'll have the cover on the bed and see what kinda numbers I can squeak out.

Here is a 40,000 + mile fuel mileage report. It should reduce the error of filling the tank. All tank fills are until pump cuts off no filling higher.

Best tank Cartersvill GA to West side of St Louis 542 miles on cruise 70 MPH 21.156 MPG

Total fuel mileage since truck was new 17.335 over 40,956 miles

Total fuel cost per mile $0.187

Mile per hour average for 40,956 miles 34.135

In the attached excel spreadsheet you can see the detail. Look for things like the mile per hour for a tank and note that if its low for congested driving then the fuel mileage suffers. If the MPH is higher than its better.

Note the error in the DCI. Its 3.720% since I started tracking this error.

My findings:
If i drive 50 MPH the fuel mileage on the DCI is 23 or 24 depending on season and outside temp.

If I drive 60 MPH then the MPG drops to 21-22.

If I drive 70 MPH then it drops to 18-19

If I drive 75 then it falls to 17-18

Around town on surface streets I have seen as low as 12 MPG In stop-and-go traffic at 25 MPH

Driving style/speed really impact MPG on this vehicle.

This is just my experience. Would love to see anyone else's experience that has documentation.
Nice work :D

I pull trailers on occasion. Most are hauling light to mid weight flat bed loads. I have on occasion pulled a dump trailer loaded its 15k. Never pull a trailer for a complete tank though. 98% is with out a trailer.

22.4MPG is my best and I didn't cheat the fuel pump either because it kicked off @$100 and I had to start all over again. 67 to 68 MPH. Wish that I could get my towing mileage over 12 MPG though.

For me, regular driving is 17-20mpg, but if I run the stock tires (the crappy low rolling resistance skinny ass tires) at 60psi, and accelerate like an old man, set the cruise at 56mph, with the predator set to 120hp, and boost stick plugged in, I can get 25-26mpg. hand calculated. Granted this is with a regular cab running empty with a topper, but hey, 25-26mpg aint too shabby for a 3/4 ton truck!

Fuel volume was/is calculated to the top of my bed tank, So it is definately full...

I have yet to get an accurate unloaded mpg figure for my 07 Classic cc 4x4 DMAX. This last tank was looking awesome until my father in-law decided to fill my truck up without telling me (tank was just below half). I was pretty pissed because it looked like I was getting at least 22mpg with my DMAX.

SP

With all the time you guys spend monitoring your driving, DIC and other countless things to get good/higher MPG why not just buy EFI-Live and spend some time on learning how to build tunes and tune your drivetrain for X application..

I've had EFI-Live for the past few weeks and out of the 80+ tunes I've flashed in that, I've either built or got from another EFI'r my best MPG has been 32.8 in a 160+mi cycle of mix hwy/cty and a few flogs up to 130mph range... And that was with a 426rwhp tune w/my driveablity/mpg tweeks.

If you think low 20's are great then you've got something to look foward to.. EFI-Live!!

I've had EFI-Live for the past few weeks and out of the 80+ tunes I've flashed in that, I've either built or got from another EFI'r my best MPG has been 32.8 in a 160+mi cycle of mix hwy/cty and a few flogs up to 130mph range... And that was with a 426rwhp tune w/my driveablity/mpg tweeks.

If you think low 20's are great then you've got something to look foward to.. EFI-Live!!

So, was that 32.8 MPG hand calculated, or was that what the DIC noted?

Mine gets 17 highway. Thats about it...wish i got close to 20!!

I've had EFI-Live for the past few weeks and out of the 80+ tunes I've flashed in that, I've either built or got from another EFI'r my best MPG has been 32.8 in a 160+mi cycle of mix hwy/cty and a few flogs up to 130mph range... And that was with a 426rwhp tune w/my driveablity/mpg tweeks.

If you think low 20's are great then you've got something to look foward to.. EFI-Live!!

callin some bs on that one

Ya'll can Call Bullcrap all you want to or not, if you tune it right with EFI Live anything is possible but you really have to know what your doing to get that good of milage

I would just like to know if the mpg was hand calcd.

If so, wow!

if anything is possible with EFI live, then where are the 50+mpg tunes at? BULL $H*T 32+mpg out of one of these trucks, if you had a tune like that, you would be a millionair, as everyone would be willing to pay big money for it, and the oil companies would buy it and the rights to it from you.

Why is there always someone that has to feel like they need to one up everyone else? This is rediculous. Always someone trying to peddle their wares.....

I haven't gone any real distance with my truck without some kind of trailer behind it. A couple of weeks ago I got to drive round trip from Columbus, Ohio area to Charlottesville, VA area without a trailer. Just four of us with clothes and food for a week.

On the way there I was running 70-75 and got 18.75 hand calculated. On the way back I tried to stay 65-70 and got 19.25 hand calculated.

This was with the Predator in at 65 hp, with MPH dead on thanks to the programmer, and using about 1 ounce of RBP additive per 20 gallons of #2.

Considering the truck only has 15K on it, I'm happy.

Mike

The point is here that driving style/conditions GREATLY affect fuel economy. I too get good hiway numbers over 20, but as I have posted many times, wind conditions will dramatically impact fuel economy, even more so I think than top speed.

Nice job on the spreadsheet.

To those guys out there reading this thread that are getting what you feel are poor mumbers, you gotta be real critical of your driving style if you want good MPG numbers

Added MBRP cat-back and saw no improvement in mileage,19+.A change of jobsite location and driving habit got me into the 22+ range which frankly I thought was not possible.Always hand calculate and fill the tank to the cap and run full tanks if possible.The route this mileage has been recorded for the last four tanks is fairly flat consisting of 250 miles of two lane and 153 of four lane,this a weekly run from Tomah,WI to Peshtigo,WI and back to Tomah on a single tank of fuel.There are only 2 cold starts for this weekly trip as truck sits during the week in Peshtigo.Speeds are roughly 60 mph on two lane and 64 on the four lane,it takes a lot for me to hold that speed down to 64 but I am looking for mpg and consistency.The four tanks so far 22.9,22.3,22.2 and 22.0.As you can see my cosistency is dropping ever so much as a little flogging of the D/M is returning.I do make kicker in the a$$ passes on the two lane STH 21 as thats the only way to pass some real slowpokes,hit 90 mph passing 5 of them in one shot.The only other mod to this truck besides the exhaust and gauges was removing the rubber tube in bottom of air box.Truck has 16,000 miles on it and run 60 psi front and 55 psi rear tires.

my buddy is getting around 22-23mpg in his LBZ. another one gets 23mpg on his 500HP tune. and then i get 20 in the city and 25+ on the highway. just takes a little tuning

The point is here that driving style/conditions GREATLY affect fuel economy. I too get good hiway numbers over 20, but as I have posted many times, wind conditions will dramatically impact fuel economy, even more so I think than top speed.

Nice job on the spreadsheet.

To those guys out there reading this thread that are getting what you feel are poor mumbers, you gotta be real critical of your driving style if you want good MPG numbers


Very true, I have seen several conditions were mpg tanked to ~16. That would include kansas headwinds, and southern cal driving or what I consider real city driving. There are tons of stoplights and no real chance to "cruise"

...To those guys out there reading this thread that are getting what you feel are poor mumbers, you gotta be real critical of your driving style if you want good MPG numbers

Yep, that was the biggest difference for my fuel economy. Going from driving 75+ mph to reducing my velocity to 63-65 mph is when I crossed the 20 MPG threshold. I know that speed seems really slow, but I figure I'm usually not trying to hit a moving target, so I should try and squeeze as many MPGs as I can on these long drives. Now, it's kind of a motivational thing to try and reach 22 MPGs when the temps cool off (the best hand-calculated I was able to achieve on my 820+ drives was 21.88 MPG when the temps were between 60-70 degrees).

Please note my fuel mileage is for the total mileage on the truck not just one tank. On long trips I have been able to get 20 + MPG for a tank or two.

But I don't normally drive long distances and I don't always drive 65 MPH. The normal driving includes long trips and local stop light driving plus some towing.

Fuel mileage numbers from on or two tanks have two many errors possible. DCI readings also have errors in them. The DCI is an algorithm so its a best guess.TOTAL mileage on the truck which weight in at 7150 lbs without driver and nothing in the bed. That the mileage I have shown is acceptable at least me.

If you are getting bad mileage look first at driving style.

For me, regular driving is 17-20mpg, but if I run the stock tires (the crappy low rolling resistance skinny ass tires) at 60psi, and accelerate like an old man, set the cruise at 56mph, with the predator set to 120hp, and boost stick plugged in, I can get 25-26mpg. hand calculated. Granted this is with a regular cab running empty with a topper, but hey, 25-26mpg aint too shabby for a 3/4 ton truck!

Fuel volume was/is calculated to the top of my bed tank, So it is definately full...



Ain't to shabby????


Thats F'n awsome for in town!



I get anywhere from 19.5- 20.5.......it also depends on how many ford feel froggy.

Just drove almost 800 miles, First tank average speed was about 65 to 70 and I got 22.6 mpg, Second tank was 21.5 cruise set at 73 mph, and the third tank was 21.2 cruise set at 75-80. This was not DIC readings b/c it read 28 plus. I filled up at 1/4 tank for the first 2 tanks and I filled up when I got to MS even though I still had ove 3/4 tank left.

I have to make my 820+ mile freeway trek again next weekend, but plan to drive the wife's C2500HD LBZ (in the sig) this next time - tired of putting all the miles on the dually. With the weather expected to be cooler, I'm hoping for 22+. I'll report back after Labor Day when I get back home.

I logged a ~530 mile hiway trip @ 72 mph on Monday and got 20.8 mpg with the KD performance/tow tune. Pretty happy with that. It is my best so far with the LBZ.

I accidentally created a sick milage tune when i was aiming for smoke... avg. 23+ mixed city/backroads... barely any highway :D

Cowdoc, I want what you have, I think. How is the power, egt's, and shifts compared to different levels on the Diablo? I cant remember, did you buy another ecm and have John load the tune loaded on it?

Cowdoc, I want what you have, I think. How is the power, egt's, and shifts compared to different levels on the Diablo? I cant remember, did you buy another ecm and have John load the tune loaded on it?

The power and shifts are very smooth. I haven't had the chance to tow with this tune yet so I can't give you a good comparison to a Predator tune, although I can say that it feel stronger than the 65 hp tune. EGT's are 50-75 degrees cooler and boost is 2 psi lower than the Pred on 65 cruising on the hiway @ 72 mph. I can't wait to tow with it to get a good fel for where power, egt's and boost are going to be.
I purchased the tuned ecm from John and kept the factory ecm. I really like it so far it was just EXPENSIVE. But...........if you put a lot of miles on your truck like I do it will pay for itself in fuel savings. I put 45-50k a year on my truck and it will take a year for it to pay off, but I will keep the truck until it has 250k on it. So, I figured that for me at least it was worth it. If I wasn't too scared of it what I would have done is bought EFI and used it but I was afraid I would fry something. I will knnow more when get some more miles on it on the hiway, rural driving and towing.

The power and shifts are very smooth. I haven't had the chance to tow with this tune yet so I can't give you a good comparison to a Predator tune, although I can say that it feel stronger than the 65 hp tune. EGT's are 50-75 degrees cooler and boost is 2 psi lower than the Pred on 65 cruising on the hiway @ 72 mph. I can't wait to tow with it to get a good fel for where power, egt's and boost are going to be.
I purchased the tuned ecm from John and kept the factory ecm. I really like it so far it was just EXPENSIVE. But...........if you put a lot of miles on your truck like I do it will pay for itself in fuel savings. I put 45-50k a year on my truck and it will take a year for it to pay off, but I will keep the truck until it has 250k on it. So, I figured that for me at least it was worth it. If I wasn't too scared of it what I would have done is bought EFI and used it but I was afraid I would fry something. I will knnow more when get some more miles on it on the hiway, rural driving and towing.

I need to edit the hilighted part above. After driving a little more I would have to say that the egt's are more like 25-50 degrees cooler instead of 50-75. Boost is 2 psi less though.

My best with stock tires was 21mpg back and forth to work. Got 24mpg (empty) on highway once going about 70mph average the whole time. Now that i put on 285's,back and forth to work dropped to 19mpg. Havent been empty for a highway trip yet. I got Diablo set on economy, cai, and 4"cat back. no muff.

I need to edit the hilighted part above. After driving a little more I would have to say that the egt's are more like 25-50 degrees cooler instead of 50-75. Boost is 2 psi less though.

Just out of curiosity, what are you seeing for boost on the hwy?

Just out of curiosity, what are you seeing for boost on the hwy?

3-5 psi @ 72 mph.

http://www.dieselplace.com/forum/images/buttons/viewpost.gif (http://www.dieselplace.com/forum/showthread.php?p=2815595#post2815595) Strange - I have 2007 Classic that is completely stock. I get 19 to 21 mpg drving at 65 with AC on and cruise.

I also get around 12 towing 27 foot toy hauler fully full of water, gas, and 2 atvs.
I get similar if not better #`s with my truck. Just did a 900 mile trip and got 684 miles on the tank when the fuel light finally came on. 2miles later I filled her up and it took 30.3. This was my best ever average 22.6. Had a light load ,1 dirt bike in the bed gear,wife dog,etc. I stayed out of the power cruised no more than 62 and had favorable winds both ways.Temps were mild so ac was off most of the trip.Amsoil fuel conditioner and cetane boost were in the fuel and has proven to me to perform better than Stanadyne performance formula or Howe`s diesel treat.sure do like this truck!:p: __________________

3-5 psi @ 72 mph.

That is pretty good, I'm usually at 7-9 psi around 70-72mph.

I have to make my 820+ mile freeway trek again next weekend, but plan to drive the wife's C2500HD LBZ (in the sig) this next time - tired of putting all the miles on the dually. With the weather expected to be cooler, I'm hoping for 22+. I'll report back after I get back home.

Just finished adding up the receipts from our Labor Day weekend trip...it was a lot hotter than expected on the way up to NorCal (Friday, 8/29) 105-107 degrees through Kern, Kings, Fresno, Merced, Stanislaus and San Joaquin Counties with a bit of a headwind. My boost gauge was between 8-9 psi the entire trip north, and since the wife was with me, the AC was on the entire time.

The trip back took us through the SF Bay Area on Saturday and then drove back home yesterday afternoon. Ambient was 85 degrees and the boost gauge was at 4 psi - AC on as well. I also towed a horse trailer to deliver a horse to a ranch 51 miles away last night, which added an extra 100 miles to the total miles. Here are the hand-calculated figures:

Traveled: 928.3 miles
Fuel Used: 44.43 gallons of diesel

Average MPG: 20.89 - I figure that's pretty good all things considered for the 2500HD.

I am jealous. I wish someone would figure out the secret sauce that seems to cause the large variation. Even when I drive like a grandma, with the AC off, keeping RPMs below 1700-1800 at all times, the best average I can ever get is 16-17 on the highway. Around town is closer to 14 and some change. I would kill to see a tank at 20mpgs.

I normally get 15-16 city and 18-20 highway. I did see 22 on the dic one time. Most of the time my dic shows 15.5 since most of my driving is city and rural driving. I have seen as low as 14 in town depending on my right foot. The average speed for my truck is 33 mph and that's using the miles divided by the engine hours. I have a friend that's got a 07 just like mine and he gets around 2 mpg lower than I do. Driving style has a huge effect on mpg.

Yep, with driving style affecting fuel economy the most, I found that weather has a significant impact on my fuel economy. For my drive up to NorCal on Friday when it was really hot, I traveled 355 miles and the tank took 17.96 gallons, for 19.76 MPG (I fill to the same spot in the filler neck). Which means the truck got 21.65 MPG for the trip back that included pulling a horse trailer for 100+ miles. I figure without having to pull the horse trailer and if it was 85 degrees on the drive Friday, I probably would have reached 22 MPG.

I normally get 15-16 city and 18-20 highway. I did see 22 on the dic one time. Most of the time my dic shows 15.5 since most of my driving is city and rural driving. I have seen as low as 14 in town depending on my right foot. The average speed for my truck is 33 mph and that's using the miles divided by the engine hours. I have a friend that's got a 07 just like mine and he gets around 2 mpg lower than I do. Driving style has a huge effect on mpg.

I wouldn't trust the DIC as they are usually incorrect, unless you have hand calculated your mpg and it's the same as the DIC.

I am jealous. I wish someone would figure out the secret sauce that seems to cause the large variation. Even when I drive like a grandma, with the AC off, keeping RPMs below 1700-1800 at all times, the best average I can ever get is 16-17 on the highway. Around town is closer to 14 and some change. I would kill to see a tank at 20mpgs.

Those are close to the numbers I got before I bought EFILive. You need a tuner to get higher mileage. Over the Labor Day weekend, I drove to Pinedale, WY from Boise . Driving on I84 from Boise to Idaho Falls (305 mi) I got 20.2 mpg at 78 mph. From Idaho Falls to Pinedale WY and back I got 21.15 at 70 mph. All numbers were hand calculated...

I am running an IdahoRob tow tune that I dyno'd 421hp/768tq last fall.

Rob

I wouldn't trust the DIC as they are usually incorrect, unless you have hand calculated your mpg and it's the same as the DIC.
Hand calculated is usually .75-1.0 mpg higher than the dic. I basically quit checking mpg by hand and go by the dic. I did the hand calculating for the first 15k miles I put on the truck and the dic was always lower than the hand cal. figures. Also I can never put the amount of fuel the dic shows back into the tank. If the dic shows 21.6 I might get 20-20.7 gal back in it. I fill the tank until the pump stops and hit it again until it stops the second time. The dic has held to this for 28k miles now so if it shows 15 mpg it's really closer to 16 mpg. Really if this truck does 15 mpg 90% of the time like it has so far I'll be pleased. Also if it does 18-19 highway @ 70 mph 10% of the time I'll be pleased so I guess I'm happy with it 100 % of the time.:D

I am jealous. I wish someone would figure out the secret sauce that seems to cause the large variation. Even when I drive like a grandma, with the AC off, keeping RPMs below 1700-1800 at all times, the best average I can ever get is 16-17 on the highway. Around town is closer to 14 and some change. I would kill to see a tank at 20mpgs.

I think your fuel mileage numbers are just about in line with what I would get if I was running 285-sized tires (we are running the stock-sized 245 tires on the wife's truck). Did you recalibrate your truck for tire size change? When I put larger tires on my '88 dually, my mileage dropped about 5-8%...since then, I always run the stock-sized tires on my trucks.

I am jealous. I wish someone would figure out the secret sauce that seems to cause the large variation. Even when I drive like a grandma, with the AC off, keeping RPMs below 1700-1800 at all times, the best average I can ever get is 16-17 on the highway. Around town is closer to 14 and some change. I would kill to see a tank at 20mpgs.


Thats about where I am at also ( but I am runnin the ac ) it's friggin hot here in S.E. TX. Just got back from a Dallas trip 500+ miles round trip pulling a 7'x12' enclosed trailer packed W/ all my crap got about 11.5
The route was kinda hill-ey though

on a road trip this past spring with my ppe on 225 setting i recorded 22.6mpg

On Labor Day I drove from Bishop, CA to Simi Valley CA pulling a 2500lb trailer. Then drove the truck back over to storage to drop off my bikes and quads, then drove the truck two days to work. I averaged 17.5mph (hand calculated). All this was with the a/c on and going 65mph (verified with my GPS), truck was full of kids and the bed full of camping gear. I have a 07 classic, D/A 4x4 crew cab short box completely stock.

SP

Here is my mileage pix....

haha yea were you going down hill while being behind a 18 wheeler?wish that was a real number

Here is my mileage pix....

Thats nothin....saw 99.9mpg last weekend will towing the boat!!! (down a 18% grade):D

I had a 2004 2500HD Reg cab 8' bed, LLY with a ML6 manual transmission. Taking my 800 mile trip from Ft. Campbell Ky to Port Deposit Md I would drive 75 to 80 MPH. With the 36 gallon tank full I could drive 620 miles and still have 1/8th tank left, and that truck was bone stock.

I get 300 miles to a 26 gal tank... Straight exhaust, Bullydog, Xdi truflow intake. Sucks..

I get 300 miles to a 26 gal tank... Straight exhaust, Bullydog, Xdi truflow intake. Sucks..

Ouch...what other mods do you have on your truck? Is it lifted, larger tires, etc? We get about 540 miles to the 26 gallon tank on the stock 2500HD in my sig.

Not lifted any. Have BF Goodwrich 285s. Front end replacement. Not sure what the deal is.

sounds like you need some good old fashion EFI Live tuning.

I know there are some people who doubt that a CC, LB, DRW LBZ (my '07 GMC in my sig) can get anywhere close to 20 mpg, even some of my friends (mostly my friends who own 6.0/6.4 PowerStrokes) doubt me, but I finally had a camera with me when I made my monthly 820.8 mile trip up to Northern California. Attached is the photo of my dash after I filled up when I got home. This last trip, over the weekend, was actually my worst mileage of my last 5 trips. I think it was because the ambient temperature was consistently 105 degrees and my intake temp hovered around 110 degrees the entire time. My range has actually read 680+ during the Spring time when ambient temps were below 80 degrees, and I almost got 22 mpg. On this last trip, my DIC noted that I used 40.1 gallons of diesel, but I actually put in 38.17 - my DIC consistently records about 5% on the high side of fuel used. Even going by the DIC, my mileage is 20+ mpg. I just thought I would post some encouragement and help offer up some evidence to the other LBZ guys who get doubted about their 20+ mpg mileage claims.


My '06 CC DRW LBZ 4WD has gotten just over 20 MPG on a long staight sea level run in Florida...It was hot! I was also averaging 70+ MPH...If i had averaged 60 mph, I probably would have gotten better. I am thinking of getting a tonneau cover to help with MPG

BoiseRob, I have a tuner. I am running the Hypertech PP3 on stage 2.

Vin63, The milage I quoted takes into account the 6-8% gain for the larger tires. I did not adjust my computer so my warranty lasts a little longer.

Looks like I may need to get an EFI Live tuner to play around with.

I can go with you on that went from lake havasu az to colorado springs co and was getting 20 to 22 mpg up and back

I know there are some people who doubt that a CC, LB, DRW LBZ (my '07 GMC in my sig) can get anywhere close to 20 mpg, even some of my friends (mostly my friends who own 6.0/6.4 PowerStrokes) doubt me, but I finally had a camera with me when I made my monthly 820.8 mile trip up to Northern California. Attached is the photo of my dash after I filled up when I got home. This last trip, over the weekend, was actually my worst mileage of my last 5 trips. I think it was because the ambient temperature was consistently 105 degrees and my intake temp hovered around 110 degrees the entire time. My range has actually read 680+ during the Spring time when ambient temps were below 80 degrees, and I almost got 22 mpg. On this last trip, my DIC noted that I used 40.1 gallons of diesel, but I actually put in 38.17 - my DIC consistently records about 5% on the high side of fuel used. Even going by the DIC, my mileage is 20+ mpg. I just thought I would post some encouragement and help offer up some evidence to the other LBZ guys who get doubted about their 20+ mpg mileage claims.



GET SOME NEW FRIENDS,WTF

I can hardly stand to talk to people that drive fords

GET SOME NEW FRIENDS,WTF

I can hardly stand to talk to people that drive fords

x2 Ford Owners Suck... They always bring up the fact that GM had the 6.2 & 6.5 liters. Who cares! We learned from our past and since 2001, have been the dominant V8 diesel. Sucks to be You...

Rant Over,

Rob

Got just over 20 mpg with my 2006 LLY running 65-70 on a full tank running from SW colorado to NE colorado over multiple mtn passes. Bone stock when it comes to engine, tranny, drivetrain, etc. NO TUNER

Got just over 20 mpg with my 2006 LLY running 65-70 on a full tank running from SW colorado to NE colorado over multiple mtn passes. Bone stock when it comes to engine, tranny, drivetrain, etc. NO TUNER

That is great fuel mileage factoring in the elevation! - some of those passes are a 10K feet of elevation, or more, right? I would guess that you were pretty close to 22 MPG at sea level.

KC, with your permission I would like to copy and start entering my own info.

I am new to this forum and trying to decide which mods if any to make. At this point I'm dumping the 285s when they are done for 265s and turning my T bars down a tad.

Thanks to Cowdoc, KC and others who have been experimenting and providing good info.

Sure Beendare have a go using the spreadsheet. It has the formulas embedded to make it a Little easer. If you have questions PM me.

Just changed the oil to Rotella T 5W40. Am leaving in the morning on a long trip pulling a flatbed trailer (1,000 lbs.) with a Kawasaki Vulcan (800 lbs.). Truck bed loaded est. 2,000 lbs. Two People (400 lbs.) One dog (65 lbs.).

KC to Virginia Beach, VA, then to Syracuse, NY, then Niagara Falls, NY, then Kalamazoo, MI and return home. Over 3,000 miles for trip. Should began to collect a Little info to compare Synthetic to Dino oil. I will see if there is a noticeable change in mileage.

Roy

x2 Ford Owners Suck... They always bring up the fact that GM had the 6.2 & 6.5 liters. Who cares! We learned from our past and since 2001, have been the dominant V8 diesel. Sucks to be You...

Rant Over,

Rob

Just bring up that POS 6.9 diesel that Ford had!

Ford owners just cannot suck up to the fact that their mileage is terrible.I can tell about my 22 plus mileage and its in one ear and out the other.A co-worker parked his 04 Ford with the 6.0,says 14 mpg is all he can get and just gives up,cant believe what I tell him.Wifes cousin had an 04 Ford with the 6.0 and claims to have got 19.0 mpg and trades for an 07 Ford with the 6.4.Guess what, now 12 mpg,havent told him yet about my 22.0 plus.So I let the cat out of the bag and he just changes the subject.Whats really disturbing about Ford owners is how they brainwash their wives and children and it goes on and on!

Ford owners just cannot suck up to the fact that their mileage is terrible.I can tell about my 22 plus mileage and its in one ear and out the other.A co-worker parked his 04 Ford with the 6.0,says 14 mpg is all he can get and just gives up,cant believe what I tell him.Wifes cousin had an 04 Ford with the 6.0 and claims to have got 19.0 mpg and trades for an 07 Ford with the 6.4.Guess what, now 12 mpg,havent told him yet about my 22.0 plus.So I let the cat out of the bag and he just changes the subject.Whats really disturbing about Ford owners is how they brainwash their wives and children and it goes on and on!

hey not all Ford owners do that. my buddy's parents own a 7.3 and love it. but ever since he got his Dmax they have been thing about coming over to our side.

That is great fuel mileage factoring in the elevation! - some of those passes are a 10K feet of elevation, or more, right? I would guess that you were pretty close to 22 MPG at sea level.
Yes, several over 10k feet is a few places. She loves the open highway. Only 'non-stock' affecting mileage(forgot to mention) above is tire/wheel combo. 265's in liew of 245's so DIC said 19.8 and hand calc using a 3% adjustment for larger tire diameter and revs/mile adjustment. It's actually closer to 4%, but I use 3% to be conservative.

I love this truck

I wish someone could tell me how to get 22 mpg. My truck prefers to stay around 14 for daily driving and maybe 16 on the highway.

Have you modified with say, Six Gun Tuner or the like? I'm only gettin 14.1 now. truck only has 25k ('07 LBZ) Wondering if a tuner is the way to go for better MPG. I don't need more speed or torque..just better milage....suggestions??

I don't know about your driving habits, but mine are steady and sure. I recently got 24mpg going from Winslow, Arizona to Fort Collins, Colorado (north of Denver) via freeways, at 68mph. On the return trip, I got a little better, but less than another 1mpg.

With a stock truck I dont see how anyone is getting 24 mpg. Mine was stock for a little while and 12 mpg was about it. I dont drive that fast and there is no way my truck could get 24mpg.

Im not sure this is 100% accurate but I filled my 32 gallon tank here in Va beach and drove straight through to Walton, NY. (if youve ever ben on 476 you'll know there is some serious hills) I averaged about 60-70mph and pushed it up over 90 on some hills to see what it could do. made 3 stops for snacks and drainage purposes. got to my destiation in NY with the needle resting just under 1/2 tank. doing the math its around 27mpg, I dont believe that cuz my math sucks, but I do believe I was getting well over 20mpg and that keeps me happy.

I just got back home from my trip up North again. This time I was loaded with about 1500 lbs in the bed (complete engine, complete 12-bolt rearend, TH400 trans, shop crane and other various equipment) up and back dropping off and delivering drivetrain parts. I traveled 840.4 miles round trip and the tank took 39.51 gallons (the DIC noted I used 42 gallons). The difference was that the tempurature was 20-25 degrees cooler than last month. My boost gauge was right between 3-4 psi, maintaining 65 mph (instead of 7-9 psi last month). I'm sure I would have eclipsed the 21.5 mpg mark, which would have been my all time MPG for the truck if I was unloaded.

Just bring up that POS 6.9 diesel that Ford had!


Just the 6.9??? Wut about the pos 6.0 n 6.4? :D

With a stock truck I dont see how anyone is getting 24 mpg. Mine was stock for a little while and 12 mpg was about it. I dont drive that fast and there is no way my truck could get 24mpg.
Not seeting 24, I am skeptical that anyone gets that unless they have done some significant mods. However, I consistently get over 20 on the highways in Colorado mtns (up/down alot) when unloaded and keeping speeds reasonable i.e. 67-70mph. I get 17-17.5 in town consistently.

6spd ally with 2006LLY, no performance mods, slightly larger than stock tires.

2007 Classic bone stock. and 64,000 miles. (stock tires too still, but they are shot now) Anyway I commute 72 miles one way 5 days a week. 35 miles are thruway with the CC set at 75. Every tank this summer has been over 20mpg, average is 20.2, best is 20.8.

I can get 21+ on my highway trips using cruise control set @ 64 mph.

My wife took the truck last weekend to visit relatives in Allentown , PA. She must have went real slow because she used 1/2 tank gas there and back . DIC said 22.7! It has been very accurate as far as gallons used vs amount pumped at pump. Truck all stock w/synthetic oil everywhere but trans. !6k miles

I've discovered 4 reasons to get less than 20 mpg.

1. Lots of cold starts per tank.
2. City driving.
3. High profile towing.
4. Heavy right foot.

What would you say your "city" mpg would be?

To me "City" means LA, orange county, san diego with tons of stoplights and rarely getting to cruise for more than a minute. Im getting ~16 when purely city.

I cant wait to get back on the road and head back to kansas. :driver:

Thats some preatty good mpgs for full size trucks

Ive managed to get 26 hand calc'd at 61mph with the tires at 80 psi and the front end taped off like diesel power mag did to their dodge

My best was 22.4MPG empty on the highway. I got 20.4 MPG last week on way down to Virginia and 21.4MPG on the way back. That is mostly at 67 to 68MPH. For about 20 miles though I ran at 65 just cause the road (15 around Gettysburg) is posted at 55 MPH.

Ive managed to get 26 hand calc'd at 61mph with the tires at 80 psi and the front end taped off like diesel power mag did to their dodge

That's interesting...what were your water temps and EGTs like when you did that? On my way up North each month, I stop at the Flying J on Jack Tone Road to do my first stop mileage calculations (my family lives in Ripon).

The greatest gain in fuel mileage for me has come from the turbo back exhaust system....

With the stock exhaust, I would get about 20-20.5 at 70. If I pushed the truck harder the mileage would drop over 70, in a linear fashion over 80....

I've had the exhaust on the truck for a couple months now and I can push the truck 80-85 mph, and average 20.4-20.8 now and at 65-70 mph, be around 21.5-22. That is hand calculated... my display is within .2.

an article in last months dieselpower said below like 50 mph its mostly rolling resitance that affects economy. above 50 its mostly aerodynamics.

how are yall getting in the 20s on the highway. i mean 26 mpg in a 9k lb truck is insae. i set the quad on economy and got 17.4 in a 3hr trip. all freeway and went through 2 or 3 small towns. probably averaged 67ish mph

Just took a 350 mile trip today and got 19.29 hand calculated. Mostly 60-65 mph, went thru many small towns and a little interstate at 70 mph. I can live with that.

Well I would have to say if you go with EFI Live you can get any where from 20 to 26 mpg I am running the twister smoke tune in my 07 classic. I am getting 22 with a heavy right foot in the city and close to 26 on the hwy 70-80 mph. If you are wanting better mpg go with EFI Live. That is the only way to go. It is worth the 750$ cost if you drive your rig alot. It pays for itself in a few months. J M I!!!!!

damnit just when i bought a quad i should have got efi live

I'm getting ~21mpg @ 60mpg highway stock. Someday I plan on putting on a tune and hope then I can get the ~26mpg. :)

Well I would have to say if you go with EFI Live you can get any where from 20 to 26 mpg I am running the twister smoke tune in my 07 classic. I am getting 22 with a heavy right foot in the city and close to 26 on the hwy 70-80 mph. If you are wanting better mpg go with EFI Live. That is the only way to go. It is worth the 750$ cost if you drive your rig alot. It pays for itself in a few months. J M I!!!!!

You sure those are hand calc'd? I tested this tune out and it reported back 23+ mpgs when i was really getting around 15. :rolleyes:

I know there are some people who doubt that a CC, LB, DRW LBZ (my '07 GMC in my sig) can get anywhere close to 20 mpg, even some of my friends (mostly my friends who own 6.0/6.4 PowerStrokes) doubt me, but I finally had a camera with me when I made my monthly 820.8 mile trip up to Northern California. Attached is the photo of my dash after I filled up when I got home. This last trip, over the weekend, was actually my worst mileage of my last 5 trips. I think it was because the ambient temperature was consistently 105 degrees and my intake temp hovered around 110 degrees the entire time. My range has actually read 680+ during the Spring time when ambient temps were below 80 degrees, and I almost got 22 mpg. On this last trip, my DIC noted that I used 40.1 gallons of diesel, but I actually put in 38.17 - my DIC consistently records about 5% on the high side of fuel used. Even going by the DIC, my mileage is 20+ mpg. I just thought I would post some encouragement and help offer up some evidence to the other LBZ guys who get doubted about their 20+ mpg mileage claims.

That's awesome....

what have you done to your truck .......!!!!

i got stuck driving around 45 miles per hour for nearly 4 hrs. once.... it came out with something like 24 mpg's [ and it sucked!!)

i got stuck driving around 45 miles per hour for nearly 4 hrs. once.... it came out with something like 24 mpg's [ and it sucked!!)

Ouch!...that would suck. But, it could have been worse - at least you got really good fuel mileage. I once trailered back from a Labor Day weekend race at Las Vegas and it took me 9.5 hours to drive home because of the holiday traffic, various accidents and road construction...I never got over 20 mph. My poor 7.4L got ~4 MPG - mostly idling on I-15. I had to fill up twice on the way back to Chino Hills - about a 200 mile trip.

when you use a tuner to calibrate for the tire size, wouldn't this put your DIC spot on? Or right at it? considering it tracks your mileage based on what you set your tire size to and how many gallons of fuel its used.. this is the same we're doing when doing the math ourselves, or am I missing something?

when you use a tuner to calibrate for the tire size, wouldn't this put your DIC spot on? Or right at it? considering it tracks your mileage based on what you set your tire size to and how many gallons of fuel its used.. this is the same we're doing when doing the math ourselves, or am I missing something?


I used my PPE to change tire size and a GPS to check my speedo. The speedo is dead on. Everything on the DIC is off....do a search on a couple threads I started to see some differing results. I think I posted a thread last year and one this year.

Everything on the DIC is off....do a search on a couple threads I started to see some differing results.

The DIC on my dually is right around 5% off on the high side when it comes to fuel used (always reads more fuel used than what I can physically put back into the tank). Our 2500HD's DIC is pretty close to being dead on.

Chris is right, the best thing that ever happened to my highway mileage was the exhaust. The trucks mileage used to just spiral downward in big way at anything much over 75 but now it seems to not matter how fast i go the mileage just want drop down below about 19 and if i drive around 75 or so i can see 21-22 mpg

The DIC on my dually is right around 5% off on the high side when it comes to fuel used (always reads more fuel used than what I can physically put back into the tank). Our 2500HD's DIC is pretty close to being dead on.


Mine's just the opposite, I always put about 1 gallon more in than the DIC says I used and therefore my avg economy is always a little better on the DIC than actual. Usually about 3-4 tenths or so. According to GPS my odo is right on.

My fuel filter is reading 10% left...how much will this affect milage???? if at all.....:o:

The last few OE fuel filter changes, I waited until 0% twice, and the last one with 3%, and in each instance, I still had more than 2/3 of clean filter media, so it didn't affect my fuel mileage since I was still getting 21+ MPG on my long freeway trips in my dually. Have you noticed a drop in fuel mileage?

For the most part a fuel filter with 0% won't hurt anything. The only time a (mostly) clean filter is needed is at wot, high rpm's, with a fairly hot tune, as that is when the most fuel flow is. Keep in mind the % remaining is based on mileage, not blockage. you can change the filter, put a tank on "dirty fuel", and have it throwing low fuel pressure codes. It doesn't throw a code as soon as the pressure is low, it has to be down quite a bit (I don't know the exact amount). If you run dino for 10's of thousands of miles, then switch to bio, you may kill a filter in a tank or less, depends on the amount of crap hitting the filter.