I know that this thread has been done to death, but i just came back from a weekend trip and thought i would post up my fuel mileage report.Approx. 300 miles each wayRunning south at 76mph with a pretty stiff head wind i averaged 17.22 miles per gallon at approx. 2200rpmheaded back north at 64mph with no wind to speak of i averaged 22.35 miles per gallon at approx. 1800rpmi am happy with these numbers but they can always improve! the speed is obviously a huge factor on the economy, but i would like to do injectors and larger exhaust in the near future. any thoughts or recommendations are always welcome.i would love to see some of you guys numbers on your rigs so post away!

Check out the fuelly link in my sig. My mpg's aren't as good as yours but are better than some.

Seem you follow my 5 MPG loss rule for every 10 MPH. But there is no way I can touch your numbers...55 MPH - 22-23 MPG AVG65 MPH - 16-18 MPG AVG75 MPH - 13-15 MPG AVGNearly 200K worth of fuel mileage data.Video

I agree with the 10 mph 5mpg loss. I played with mpg s in my big trucks.. same concept smaller scale... my new to me 02 4x4 scab is getn 14.7pmg @ 70-75 mph ... Not impressed but I do have lift and bigger tires. I will drop my speed to 65 on my trip back up north Utah..

sent from my cell...

I recently ran a 350 mile trip. My average speed was about 55 mph and i got about 20.4 mpg. This is from the overhead console i didnt hand calculate it out. But i notice that your rpms are much lower than mine i rev about 2000 at 55. why such a difference?

4.10 gears?

I agree with the 10 mph 5mpg loss. I played with mpg s in my big trucks.. same concept smaller scale... my new to me 02 4x4 scab is getn 14.7pmg @ 70-75 mph ... Not impressed but I do have lift and bigger tires. I will drop my speed to 65 on my trip back up north Utah.. sent from my cell...

That is a good looking truck! I would assume that most of your mpg loss is from speed and your lift. The further from the ground the bottom of the truck is the less aerodynamically efficient it will. Also your gearing with those tires could play a big role. On the highway with those tires I would think it would improve mpgs though! Seems like it would lower rpms which should help. Around town in stop and go they will hurt your numbers though. Not sure how much on the diesels since they have additional torque.

4.10 gears?

yup your definitely right, wish i had 3.55 gears. i dont think anyone appreciates being stuck behind a big old truck cruising at 55 :banghead:

yup your definitely right, wish i had 3.55 gears. i dont think anyone appreciates being stuck behind a big old truck cruising at 55 :banghead:

I do!!! Much safer at that speed out here. Just in one month we've had 5 vehicle accidents involving excessive speed driving the canyon. All 5 accident involved a totaled vehicle and serious injuries. I've got to admit since I started driving slower at 55-60 MPH I've avoided many many accident because I was capable of slowing down even more and getting out of the way. Not to mention my fuel mileage is at least in the 20's range where most people pray to make high teens. So I can't complain. Also the difference between 55 and 65 MPH is so fractional that its not worth driving faster to get to your destination 3-4 minutes earlier and 5 MPG lower. Doesn't make any sense to me. From Home to McCall, ID - 35 miles Formula (distance / speed) = Hours x 60 = Minutes 55 MPH = 0.63 Hours = 37.8 Minutes 65 MPH = 0.53 Hours = 31.8 Minutes Really doesn't make any sense to drive reckless to gain what 6 minutes getting somewhere...

That is a good looking truck! I would assume that most of your mpg loss is from speed and your lift. The further from the ground the bottom of the truck is the less aerodynamically efficient it will. Also your gearing with those tires could play a big role. On the highway with those tires I would think it would improve mpgs though! Seems like it would lower rpms which should help. Around town in stop and go they will hurt your numbers though. Not sure how much on the diesels since they have additional torque.

Yeah.... I know the lift plays a part . But I should be getting atleast 19 I believe. I just drove back to Wyoming today and kept it at 65mph... Managed to pick up 2 mpg... (17mpg) I need to search for an issue tho because I blow white/grey smoke at idle I'm starting a thread so not to steal this one... sent from my cell...

In my 06 3500 today my average speed was 42 mph on a 300 mile road trip. I averaged 25.2 mpgs! Had a lot of people cussing me! My buddy in an 07 2500 4x4 with 6.7 only averaged about 5 mpg at 42 mph:eek:

25 mpg at that speed is pretty good I'd say...At 5 mpg I would be in danger of shooting myself.... That's nutssent from my cell...

25 mpg at that speed is pretty good I'd say...At 5 mpg I would be in danger of shooting myself.... That's nuts sent from my cell...

Well let me give just a little more info on him. He was pulling a 16'10" wide by 14' tall by 32' storage building. An I was running front escort! Sent from my DROID RAZR HD using Tapatalk 2

The mph rule definitely works for me. At 60-65 (62 is my sweet spot) I can hit 20+ mpgs and then 65 mph or more and my mpgs drop to 17-18 or less...right foot is the biggest contributor. If you can keep your foot out of it injectors will help mpgs, but don't expect gains until at least a month after the install. Ask me how I know. Gained 2 mpgs this past tank by driving like a normal human being, and maybe my first tank of supertech helped.

I am working in Terre Haute In. I have made 4 trips back home to NC. I fill up before I leave and it is 627 miles one way and I am running 75 mph. I fill up when I get home or back to work. Every time it takes 33 gallons +or- a 1/4 gallon. That is 19 mpg. Before the RV's I got 18 mpg for similar trips.

Been driving the truck to work more lately, ran 403 miles before I filled up, she took 19.3 gallons for an avg of 20.8 mpg. That's rural driving, anywhere between 55 and 65 mph. Thats about as good as I can get, or as good as I have seen anyway.

I believe the 10mph= minus 5 in mpg at speeds over about 60mph. That's when wind resistance becomes the determining factor.

That said, my truck is very cold blooded...............the warmer it is, the better mileage MightyWhitey gets. Couple years ago I posted a this thread......http://orum.mopar1973man.com/threads/2147-New-Miles-amp-Mileage-Records?highlight=mileage+record

It's stupid hot/humid here now, but since the above post the SpynTec free-spin hub kit has improved mileage much more than I've read about. Since the weather has gotten hot around here, I've not had a tank of fuel average under 19mpg. Last tank averaged 21mpg.

Speed kills mileage!!! Plain and simple!! Michael has posted the "REAL TIME SAVINGS" by traveling at greater speeds also. It's not as huge as most think. In fact, for everyday short distance driving, it's not worht it IMHTBHO!!!

I just got done with a 275 mile trip and about 1/2 of it with the cruise set on 73MPH (freeway), and the other 1/2 the cruise was set at 59MPH (two lane). I filled up at the beginning and still have a needle's width OVER 3/4 tank left! I haven't figured it out yet, but WOW! Oh, BTW, I also run propane...

I can get 425 out of my first 1/4 tank and then 300 out of the next 5/8 when the fuel light comes on. The needle does not move till I get 120 miles on the odo. It has been like that since I took the in tank pump out. The first time I drove it after adding the AD I thought i was getting 25 mile to the gallon. Boy was I surprised when I watched the rest of it go so fast.

- - - Updated - - -

no propane here, just wishful thinking.

I just got done with a 275 mile trip and about 1/2 of it with the cruise set on 73MPH (freeway), and the other 1/2 the cruise was set at 59MPH (two lane). I filled up at the beginning and still have a needle's width OVER 3/4 tank left! I haven't figured it out yet, but WOW! Oh, BTW, I also run propane...

In my area, I pay more for propane by the gallon than I do diesel fuel. If the same is in your area, all you're doing is replacing the diesel fuel source with a more expensive fuel source...........propane. So your figures would be "skewed"!!! Just saying though.

In my area, I pay more for propane by the gallon than I do diesel fuel. If the same is in your area, all you're doing is replacing the diesel fuel source with a more expensive fuel source...........propane. So your figures would be "skewed"!!! Just saying though.

" I've wondered that too; are the guys running propane figuring in that fuel with their diesel fuel consumed?? Propane around here is 1.05 gallon (bulk). I have a couple JD 4020's that are propane powered, I fill them out of our 1000 gallon tank. Also have a 8.3 litre chevy power unit that pumps irrigation that is on propane. All in all, those rigs will burn about 50% more gallons of C3H8 than similar hp diesel engines. For me, the 1.05 propane is more economical. Diesel would have to be 1.60 or less.