Duramax MPG
 

I have an 04.5 ext cab 2500 Duramax 4x4. 305 50 20 Nitto 420s (not a crazy big or heavy all terrain/mud tire). Straight piped, egr delete, edge programmer. I get 12 mpg towing (very happy with this) and 16-17 not towing. All hand calculated numbers on different tunes except stock. I drove light footed to get the best numbers possible.

My question is, where do these 19+mpg numbers that people talk about come from? I had an 07 5.9 dodge with the same set up and best I saw out of it was 17 also.

My boating season is over so I figured this might help entertain some people including myself.

They are all pretty much full of sh*t....

Pretty much..

But keep in mind that with your rolling mass (tire and wheel) you have changed true gear ration and rolling resistance. The add-on edge are designed for when you tip in the throttle to increase fuel load for power (that's where diesel's make there power).

I see a mix of claims but from my experience a bone stock pre 2007 gets 12-14 pulling 8000 lbs at 65mph. 2007 -2010 are less for reasons of exhaust injection to clean the cat but the 2011 up seem to be better with the diesel emission fluid system.

Sound like your in the ballpark even with your mods. Pretty good!

I can get 20.5 on the highway running 70-75mph. But I avg about the same 17 mpg. I have '06 duramax with 4" straight through exhaust and Ppe program and 285/75-16 Michelin a/t

Keep in mind you are running more miles than the odometer is reading with the bigger tires. You changed your gearing. You can set the edge tunner for tire size but not sure how to do it to the fuel usage in the truck but you can do it old school style

My 2008 Southern Comfort Conversion with 35 x 20 Toyos got 7-9 towing and 11-12 empty in stock form. I deleted the DPF, blocked the EGR, added a MPRP down pipe and exhaust, EFI Live tuning with the CTS monitor and got it up to where my 05 Duramax was stock. 11-12 towing, 15 - 16 empty.

I love how the hippies in the epa make us burn more fuel to get a cleaner emission . My 2015 burns more fuel than my 2001. With the high idle and exhaust filter bullsh it

my 04' duramax with 265's, PPE (changed tire size and power lvl 2), fuel pump, 5" exhaust will do calculated 19 - 19.8 (~70mph) on highway... towing 19k back from Ozarks into Illinois calculated at 9 mph (~65mph).

That's impressive. Nauti Hoff

I changed it.
Good thing to think about though. Stock tire height compared to current is about 1.5". Do the math and that makes the circumference of the tire 5% more. Long story short, the distance you actually drive will be 5% less on your odometer making your mpg look worse than it really is.

My concern is you granny gearing that truck. Are you sure it's performing optimally?

i used a friends 04 standard cab 4x43.73 gears 285 75 16 tires and the speedo was off 5 mpg with those tires.. ran from chicago to loto and back..hand calculated 21 mpg at 70 mph..with the speedo being off it got more mpg but the speedo rir not show the extra mpg because the speedo was a little off from the bigger tires..

You drive a Ford... What would you know about optimum performance??:lolhit:

Actually, its gets great fuel mileage between now and spring, it wont burn another drop!

:picard1:I hand calculate it also. I multiply the miles (odometer reading) by 1.06 to account for the difference in tire circumference. The LB7 and LLY generations definitely get better mileage than my current LMM. Somehow the EPA feels that burning more fuel is better for the environment...

05 Crew LLY, egr delete, cat delete, turbo mouthpiece, EFI live tunes by ATP, stock tires and gear. Gets 15-16 daily driving, 11 towing heavy. Highway MPG is directly related to speed/RPM, 16 at 80 but will pull 20 or better at 65.

05 extra cab short bed. Intake, turbo mouth piece, straight piped, EGR block, lift pump, and PPE program at level 1. 15ish around town with some highway. 17 highway only and anywhere from 10-12 towing depending on how i drive. If i go up to level 3 the mileage goes up also...

Ford 86 dually 4.11 gears here. 10 to 13 MPG empty towing 12000 to 14000 lbs 7 to 8 MPG. eXPECT ECONOMY TO IMPROVE A BIT once I DEAL WITH FRONT END ALIGNMENT some bushings are shot, as are my fingers today

From another thread; applicable here:

ive never seen better than 10 towing with my 08 3500. BUT, but friends with 05 cummins. one friend has built motor, huge injectors,built tranny, 40'' tires, 10'' lift and hand calculated gets 24mpg highway running 80.... alot of it is in the custom tuning and making everything run in sync... but ya, ive never owned anything that gets 19 or so towing.

I would think terrain, elevation and wind would have a lot to do with fuel economy. A god tune with deletes is about the best you're going to get.

I had a 2005 GMC crew cab 4wd with the complete Banks kit and cat removed. Truck had 285 tires. It would get 15.9 mixed daily driving . Highway mileage if you kept it under 70 would be 18.5 mpg. Towing a 24ft enclosed trailer at 70mph it would average 10.5 mpg. Drove it from new to 100k miles and wish I still had it. Have a new 6.2 Chevy and can not get over 14mpg empty. Jeff Wurl

I like hearing people's real numbers. Sounds like we are all close. I did get 19 mpg on a short highway trip over the weekend.

have a 08, cat/egr/dpf delete, tow tune with EFI live, and just changed all the diff/transfer case fluids to amsoil, trip down to charlotte 2 weeks ago got 19.5 calculated, now it never seemed to do that well before the fluid change but not positive. Thats with 285 tires and a flush camper shell, had always heard about people getting in the 20 range and never got close before, but never done much non-tow driving either..also tune was done to correct for tire size.

I enjoyed that post, so I checked mine around town 25 to 50 mph no towing old 2006 5.9 4x4 dually........and of course the pic rotation is wrong. lol!

2008 f250 6.4 all stock 85,000 miles crew cab short bed 4x4 nothing in truck nothing on hitch 10.5 mpg highway at 80 mph + truck says 14.5 mpg.

Was that on a lift or did you run it on jack stands? :)
That's great fuel mileage!

You must have been heading downhill to the West. That's the only way that number is legit.
And your tires came off a Schwinn or a Huffy.

I developed a carburetor for diesel trucks that got 100+mpg but the big oil companies squashed it and I can't afford to fight them. Oh well.



:party-smiley-004:

With a sail. Fiddy Cent took the pic, he holds the Samsung sideways like he's firing a Glock

06 LBZ bone stock. I see 15.5+ hwy and 10.5 towing 15,000 lbs on the digital dream meter. I changed the wheels up to the 17" that the new trucks are running but used tires that are near the OE size diameter for the truck so the digital meter could possibly be on par. I plan to do deletes and programmer so I will see how much change I get.

Love this truck.

My 2001 duramax with edge tunner on the economy setting would get 20-22 mpg around town. But with the edge tunner you realize why th fu ck did I buy this thing for anyway. So it stayed in level 5 forever. But still got 16ish without romping on it and rolling coal on those hybrid vaginas. Keep in mind I have smoked mustangs from light to light with a 10 k lb truck. But I'm still pissed off that my new truck( yet only 3k miles on it) best mpg is 17. She hasn't been doing much other Han towing the boat or my machines. But I did reset the gauge after my horrible 6.8 mpg .

yes !!!!

My 2015 HD gets 20 mpg at 75 mph highway- not towing. It gets 14 towing my work trailer at 70- which is square and tall with the aerodynamics of a brick. If I tow it at 60 mph I get 16 mpg.

My 03 DMax was the best of the ones I have had. Did intake and exhaust, Bully Dog programmer, got 19mpg all day and 13-14 towing. Best part was the power, at max tune it would break the 33's loose at 30 on dry pavement. The upgrades did more on that truck than I could believe, was like a second engine under the hood.

I have had 4 of them, a 02, 04, 06 and my current 08, all Crew cab, short box 4x4's. My 04 even though it was identical to my 02 got best mileage, saw 19.5 empty running fast on highway from fla to mi turned up 90 hp over stock, it would regularly get 17-18 empty on highway at 80, 13.5 to 15 towing my 272 at 80 mph, 12.5 towing 3000 lb snowmobile trailer in winter. I run highway tires on all of them in summer and skinny snow tires in the winter, the guys with big tires look like tards in a snow storm going 45mph in 4x4 with white knuckles. My current 08 is absolutely the worst mileage out of all of them, with dpf delete, tune,it gets 10.5-12 towing my 272, 9.5 to 10 towing the new 33 scarab , 9.5 to 10.5 towing 3000 lb snowmobile trailer and 14.5 to 15 empty. Now IF I baby it on a 2 lane highway at 58 mph I could get trip computer to show 20.5 to 21 for 100 miles after resetting it but the minute you crack the throttle that drops off face of the earth. Tried every version of the tunes from econo to 150 hp, seems to get BETTER overall mileage at 70 or 90 than 50 or econo.
We rebuilt a transmission on a 04 or 05 dodge dually extended can 4wd six speed stick, had highway tires on it, no mods, I put 100+ miles on it breaking new parts in and I was in disbelief that it got 20+ mpg at 65-70 mph, too bad they ride like crap and fall apart!

Smart man. Amazes me how many people don't get this even up here! Big tires = flotation !

I was shopping for the 06-07 classic Silverado for the updated front end and 6 speed transmission but I got a good deal on my truck and it's really clean/good shape.

I'm running 2k RPMs going 70-75mph. How does the 6speed compare? Does it shift a lot between 55-65mph?

That will probably be my next truck. Crew 07 classic. I like the older preadmission trucks. Love that body style. Cash deal, lower insurance, cheaper to licenses, reliable truck is what shoot for.

Some of these guys are going by the lyometer thats a no no .

Np

Yup I used to run tall skinnies in the winter when I did a lot of trips north snowmobiling. Friends used to make fun of the "pizza cutters" but they were 1000% better on winter roads and would go through an amazing amount of fluffy lake effect snow.