Last Friday I headed out to my deer lease following my Dad pulling the equipment trailer with his F350 SD. And as usual, he drives slow while towing. So with the speed of around 62-65mph for almost 250 miles my calculations came to right at 25mpg for that run. This is with ULSD and the SMARTY set at level 3 (60+timing).
Now if I can get my around town economy up...

MikeyB

 

Yup, most people don't realize what MPH have to do with MPG. I did that ones and goet 19.2 mpg. Of course that was up to maine, so the mountains and all still used some fuel. But yes driving slow does help mpg big time.

 

I believe it. When Fuel prices went past $3/gallon I slowed up. Driving 62-65 mph I would get 23 mpg w/ my 4x4 & 315 tires.

 

So! i'm very very clear hear and understand fully. You guys are driving 650 miles plus on a tank of fuel? Eagerly awaiting your replys.

 

EVERY tank here! 60-70 mph highway miles unloaded gets 650 plus EVERY tank. Thats with the Triple Dog on stock.
Cheers
Mike
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I have never made a drive long enough to completely use all the fuel, but on a recent trip back from west Texas i got about 320 miles on half a tank. Once I got back to Dallas I ended up using the rest of the tank around the city. I ended up getting about 580 miles on that tank and when I filled up, the tank took about 32 gallons, so I had about 1-2 gallons left. I easily wouldve gotten 640-660 miles on that one tank if I had done more highway driving.

 

I've goten over 700 miles on four tanks! Routinely, i get about 620 miles on a tank. After that, I start getting uncomfortable, or worried that I will have to fuel up at a place where the diesel will be $0.30 more than the cheaper places.

BTW, I've kept fuel records on every ounce of fuel ever put into the truck, and am not giving you the 'best tank ever'. Also, the speedo has been recalibrated for the larger tires.

 

Most I ever put on my truck was 450, and that was towing hard. I don't really go long enough to run 600 miles empty (unless I visit my sister in erie) but most of the time when not trailering, I go up in the woods, cabin, or in the extream cold (winter) so I normally don't go less than half a tank (in case I get snowed in, or this or that) Most I did was 19.5 and that was loaded up to go elk hunting up in Maine, Canada. So with around 1,000lbs of gear that's what i got. Still have no idea with winter fuel, but again, roads were snowy and we only ran like 50mph, so in 4th gear that was like 1400 rpms for me, so it ran good winter front also. I haven't gotten over 20 yet

I also like keeping fuel so that the pump runs good, AND with the aftermarket pumps the pickups will start sucking air when you slosh the tank around and mine is anything less than half. Guess the bad part of an aftermarket pump is that you can't run under 1/4 tank of fuel. Good part is I have a lot more power to mess with, with no worries of fuel issues.

 

Mikey - you don't have to go out to the lease to get good mileage... just put a glass of water on the dash and commute without spilling it.

 

I have done a couple of 600+ miles without refueling. It's tough to get the bladder to hold for that long.

MikeyB

 

The most I've gone on a tank of fuel is 637 miles. I got a hand calculated 20.8mpg on that tank. I regularly get 550-575 miles per tank in 50/50 combination suburban type driving empty and pulling my 5k work trailer. Just pretend there's an egg underneath the go-pedal!!! Hey Mikey, I'd be willing to bet you couldn't get that kind of mileage up here in da nort land running winter diesel!!!!

 

i know i'm gonna get a lot of "ya rights" and crap, but the most i've got on one tank is 712 miles. cleveland and back and then up to indian river. all on one tank.

 

oh, and the wife and i have gone to mayfield, KY without having to fill up on the way down and did the same thing on the way back. one tank there and one tank back.

 

I most have a dud I just drove 1200 miles on 97 gallons.Thats less then 12.5 mpg empty 75mph on cruise

 

Two weeks ago a friend and I drove my new 2006 Ram 2500 Cummins 4x4 from Dave Smith's in Kellogg, Idaho home to Alaska. The trip took us 2 days, 9 hours from door to door (about 2,500 miles). We had about 500 pounds in back (four tires on rims, 25 spare gallons of fuel and a small amount of gear). With nothing but time on our hands, we spent quite a bit of time monitoring the trip computer and trying different speeds for fuel economy. Our best fuel efficiency came at about 55 to 58 mph, where we were able to consistently get about 21 mpg. This would be around 1,600 rpm (I've got the 3.73 rear end). The truck "wants" to go about 65 to 70 mph (around 1,800 to 2,000 rpm), but that cuts the fuel economy down to the 17.5 to 18 mpg range.
To answer your question, in my experience yes, with a 35 gallon tank, you should easily get close to 700 miles per tank if you are driving for maximum fuel efficiency. I personally try never to let my gauge go below the 1/2 tank level, though, just as a matter of personal choice.