Not sure if it applies to anyone here, but if you have larger tires (and didn't correct the speedo), your odo will show less miles than actually travelled, thus reducing your mpg (hand calculated).

Also, Canadians need to convert liters to gallons, and there are 2 definitions of gallons... US gallon is 3.78 L and imperial gallon is 4.546 L. Miles to kilometers is standard, but if two people are comparing mpg with different sized gallons, it is not a true comparison.

Just something to keep in mind when comparing... make sure it's apples to apples.

 

FWIW I always adjust to US for DTR. Can gallon is 20% larger than the US gallon or the US galln is 17% less depending on how you calculate.

I average between 20-24 (US) but I have an 03 and run about 80-90% hiway. That's around 25-31 canadian but you wouldn't like the price we pay for it.

Great mileage for an 8000# truck.

 

Wow. High of 26 mpg with an auto, 4X4, HPCR, and an 7000lb truck. That is incredible. Wish I could have got one like that.

 

I got to be a member of the 700 mile club... before I bombed the truck. I have gotten as high as 24.5 mpg (always hand calc'd), but was mostly around the 22 range with smarty. Running around tuned at 800hp though I average between 17 to 19 mpg on granny driving.

 

Yep , my 100 mpg was starting at the mountain top and coating at 65 for miles.... Kinda cool.

I found some better fuel in the south. You know we're running blended fuel up here.

I also found some 500 ppm sulphur fuel and it didn't do as well as the 15ppm stuff.

That said, I was getting 18.6 mpg at 72 mph with 34" tires and a Smarty jr set at 2. Overhead is reading 21.6. I reset every time I fill.

When I hit headwinds I ran a tank at 17.4 mpg.

Anytime I put my foot in my Smarty, mileage plummets. But I love the power.

I can get 22 mpg if I baby the truck. I can get even better for short distances, but normal everyday driving will net me 18 mpg average.

I have an auto and I know I lose a lot of fuel to that tranny.

 

mine varies. depends the speed and how many hills i hit and how much wind to. interstate i usaully get 19. driving long distance at about 70 i get up to 24 thats with no wind. and since i live in wyoming i see lots of mountains i get 16 going over the mountain passes

 

Yes, i've had speedo changed and the latest flash...The only way I have found to increase my gas mileage is change the tire size on the outloook to a real small tire......I can get close to the mileage I want with the speedo mod!

 

On any of these trucks, calc the fuel use at every fill. Crunch the miles divided by time for average speed. That, alone, will max the mpg for any vehicle: higher is better (as this is the average speed). Low speeds on highway; never stopping in town; no idling.

Anything that kills average speed kills mpg. Same for highway speeds above average mph. I've averaged 23-mpg for ALL miles the past 13,000 (no, not all highway), and the average speed has been 43.9 mph. My highway travel speed is 59-mph. There is ZERO appreciable gain in traveling faster on trips of 300-miles in time saved.

For a truck averaging 14-mpg (my previous half-ton), all miles, and mine averaging 23-mpg, I traveled 900 miles farther on 1,000-gals fuel.

Run the numbers against yourself. Don't wait for fuel to rise again (it will); become good at it now. The miles are fixed, the fuel use/cost is the variable. Step Two is to combine all trips to reduce cold starts and eliminate trip overlap.

 

There was a study done a while back on the lubricity of various additives using the industry standard three ball friction test. As I recall, it showed that MMO actually had a negative effect on the lubricity of deisel fuel. I have seen the study referred to frequenty on this site, so you can probably find it if you do some research.

 

Loose the Marvel stuff. Air up your tires and drive like Rednax says. If mileage isn't at least 17mpg something is wrong with your truck.

 

would lubricity have an effect on fuel mileage or just wear on the pumps?

i would think diesel would have to be jello to affect the lubricity of mpgs, even when a gallon of mmo added to 1 tank will still pump plenty of fuel to the motor , at least in my thoughts it sounds good

 

If that's Marvels mystery oil your using, there is a diesel fuel lubricity study floating around that reports that using it actually takes away from the baseline lubricity of pump diesel.

 

You claim that you are seeing 25-31 miles per IMPERIAL gallon. That is a huge spread.

I'll give you the benefit of the doubt on the 25 IMPG but come on....31 IMPG?

Not a chance. Not even down hill with a tail wind are you getting 31 miles per Imperial gallon HAND calculated.

 

Fairy Dust -
Some of these CTD's got sprinkled at the factory. Or was it an option -

I missed it - 12 to 14 around town 18 to 19 empty on the road hitch up the car hauler and its single digits - been this way for 6 years/100000 miles.

 

I wish I could get these so called real world mpg's. Around town I get about 10-11 and on thw highway I get around 18 but I'm not sure becasue I hardly ever drive and fillup on just a highway run. I guess running 100% BioDiesel and holding 84 gallons of fuel will do that to you.
I get around 11 highway towing my 5th wheel. So I guess I'm happy would be happier if I got more