Well I finally got 21.8mpg with almost 800 miles for the tank before a fill up.

For the record: Trip from Casper WY to Coeurd ' Aleney ID
Trip mileage: 799.2
Gallons used: 36.619
DTE mileage left: 88
How fast: 65mph cruise set
RPM's: 1800
Headwind: none
Tailwind: none
MPG overhead: 26.0
MPG: 21.8mph

It makes me feel great when I can get over 20mpg and my brother in-law Dodge V10 can maybe get 15-16 on the highway.

 

that is awesome, what did you have your quad set on?

 

My quad box is set on level 2 99% of the time.

 

How in the world did you put that much diesel in your tank? You must have been running on fumes to fill it up that much. 2 gallons over tank capacity. Unless Dodge doesn't know exactly how big their gas tanks are.

 

fuel tank vent mod lets u get a few extra gallons

 

How many miles on the truck?

Just curious because everyone says it gets better with time. I hope so, my 99 Ford V10 did as good as this '06 Dodge does at 2.5k on the odo.

 

The tank vent mod is awesome. I think I had about 3 gallons left, at most but the fuel light did not come onbefore I filled up.

 

I am almost @ 30,000 miles. I have seen 20mpg once, but have seen 18-19 pretty regular during highway driving. 21.8 is the first time.

 

Thats pretty good considering you had to go over some big mountains in southern Montana, Lookout Pass and 4th of July Pass! I take it you took I35 to I90.

 

I took I 25N to I90w to I84 to I5 South.

 

o, south..... downhill.............. that is a great # to hit and I see why you are happy, I can't imagine getting 700 on a tank, I only cracked 500 once, I don't have the vent kit & don't stand around clicking in the last few gallons, it kix off I just fill to next dollar and a go on my way.

 

The long bed trucks have a 36 gallon tank verses the 34 gallon tank on the short bed trucks. That's how he could put the 2 extra gallons in the tank.

 

I made the exact mileage (21.8) a year ago going from Lander, WY to Jackson, WY and back. I was one mile per gallon less when I repeated the trip this year, but with some road construction and follow the pilot car routine a couple of times each way. I rarely get under 20 hand calculated on a highway trip unloaded. You are right on. It is no secret that keeping rpm's below 2000 and driving 65 or less is much better on the wallet.
I have also found something interesting about mountain driving and wonder if others have similar experiences? The downhill part of the driving more than makes up for the loss of economy when I drive uphill. Because of that I seem to get slightly better fuel economy going up and over a mountain pass than driving level.

 

I noticed this same thing on our vacation last year. On flat ground I got 12-13mpg towing the travel trailer. Driving through the mountains in northern California, I got 14-14.5mpg.

 

Its been a while since I have posted around here. Got a TDI for money reasons, and cant wait to get back to a Cummins. But one of the things I have learned over at TDIclub.com (much like this place only slightly smaller ;-)) is that the TDI doesnt fuel at all when in gear and still moving if you dont have your foot on the go fast pedal. As in, the fuel injectors dont inject as long as the vehicle is moving the engine. This is, I believe, only on the manual. Anyone know if Cummins does the same? Cut fuel completely while in gear engine braking?