I just finished a trip up to Spokane, WA to pick up my son from college. I filled up in Winnimucca, NV and then drove up through Boise ID, Pendelton OR, to Spokane and finally filled up in Coeur de Alene ID with 697 miles on the odo. It took 30.0 gallons to fill it up for 23.3 mpg. Speed varied from mid 50s to high 60s depending on conditions and limits. I took it real easy on acceleration and kept my speed as even as I could. This is the best mileage I've gotten with this truck although I've bettered 20 mpg frequently. Towing a loaded 8X12 foot U-Haul trailer on the way home I got 18.4 mph on the first fill up and 19.1 when I filled at home. Again taking it real easy. Truck has 20K miles on it.

 

You guys make me sick, haha! My best on the '03 is 501 miles on a tank from Abilene to Denver, 65-75mph for the duration of the trip. I had a hella nice 65 mph tailwind out of the SE tho. I average 420 miles on a tank.

My '08 surprised me tho. Almost got 600 miles on one tank on that same trip this weekend.

You guys givin those trucks a double-shot of Old Grandad before you set off?

 

Bigiron,

The best I have gotten out of my truck when empty driving a low speeds was 20.5 mpg. Did you find some LSD or super additive to be getting 23.3 mpg from yours?

 

all i can say is WOW,, all i get from a full tank is about 400-450. i guess it has to due with the 4.10's

 

When I was out looking for my truck, I had read on Dodge's website for the model year 2005, and it's still in Dodge's Body Builder's Guide, that my truck is capable of towing 13,100 lbs., regardless of whether I have 4.10 or 3.73 ring and pinion gears. So, I bought one with the smaller ring and pinion. Granted, I don't have the extra pep that 4.11s offer, but it still tows the weight. That's why I got mine with the 3.73s... to help with fuel milage.

 

I try to preserve our 2nd amendment right so my kids can have my guns. I can put 38 gallons on my tank from dead empty with my tank vent mod. I drive no faster than 60 MPH. I routinely get at least 21.8 all highway miles 38 gl X 21.8 MPG = 828.4 miles. I've done it several times anywhere from 806 to 815 on a tank. I have a Leer cap and a Smarty but set with no timing as the rattle and ping is too much for me. However I did the tone ring mod as it is only a couple of degrees and did not increase the ping and rattle. I do draft the big rigs when I can since they drive no faster than 60 MPH as well. BTW this 800+ miles on a tank is with a 37" tires.

 

We get nearly the same milage. I'm not sure what R&P you have, but I'll bet your final drive ratio is close to what mine is. We both have some sort of timing mod- mine via the MMM city file, and I also have an ARE cab-high cap.

I guessed at your loaded tire diameter, and assumed your R&P ratio with your setup. Transfer case was not figured into equation because it's a 1:1 ratio at 60 MPH (I hope!). Transmission final gear ratios were pulled from other posts on DTS. Calculations were rounded.

MPH x Drive Ratio x 336 = RPM

Tire Diameter..........

RE48 4th gear= .69 R&P= 3.73

(60)(3.73•.69)(336) = 51886 = 1652
31.4............... 31.4

G56 6th gear= .79 R&P= 4.11

(60)(4.11•.79)(336) = 51886 = 1793
36.5...............36.5

Three things in common... cap, timing of some sort, and RPM. Assuming you do have 4.11s, then your lower RPMs is what helped you get a tad better milage.

By the way, I lived in Sac (Citrus Heights and Antelope) for a while. How's the weather?

 

I just wanted to mention something that may not have been obvious in my original post. I calculated my mpgs...
746.4 / 35.114 = 21.25 mpgs
...by using pen & paper (and calculator), not using the overhead computer, which registered a more optimistic 22.4mpg. (a ~5% increase)

 

I thought I posted my milage. I calculated 23.1 as long as I keep it at 62 or less. I have 3.73s, and auto, the MMM with the city file, and an ARE cab-high cap. I got two you you mixed up. Bigiron is the one who gets a little better milage than me.

JustLucky, how do you like your Jetta? I looked at VW's website and couldn't find a diesel, but I know they made them in '05. I considered getting one for commuting. I'm not a car guy, and don't know much about Jettas to say the least.

 

Sorry to be so slow in answering, but I've been away for a few days. The whole trip was on ULSD according to the pumps. I did recently start using Opti-Lube Summer Formula fuel additive, and I changed the air filter and fuel filter just before I left. I don't know if those things made a big difference, but I do know that they didn't hurt.

 

thats what i pretty much get with mine. right at 400 on winter fuel and 450-475 on the summer stuff.

 

Wow! you dont know how happy I am to read that post!!!!

on a few separate occasions, I've got over 800 miles to a tank with my 07 Megacab!
Now, a few times might not be a lot, but it still happened! Everybody i've told that to, told me i was full of BS, i must've made mistakes calculating my mileage, etc etc. So I finally stopped talking about, not wanting to argue the point anymore.

On I-10, driving across Texas, I set the cruise control as soon as the truck hits overdrive at like 54 mph or so. With my taller tires(35" - and six of them), it reduces my 3:73 axle ratio to maybe 3:50 ish (i'm totally guessing here). Smarty set on level 3, I just stay in the far right lane and watch EVERYBODY flying past me while i am getting my money's worth out of every last drop of precious diesel fuel in my tank.

Now, granted, it is a little frustrating to go 55 mph in a state with an 80 mph speed limit, and you certainly get some weird looks from people as they pass you, but by my calculations, by driving the way i did over the course of my 2250 mile trip, i saved about a tankful of fuel. Of course, my travel time increased substantially, but such is the cost of fuel efficiency.

Going even a few more miles per hour than 55 changed the fuel economy DRASTICALLY! I've made that 2250 mile drive 7 times, so I've had plenty of time to experiment with speed and corresponding fuel economy.

Just my 2 cents

 

My Best for my 06 is 18.6 empty..Wish it do more,19,000 on the clock.

 

I will be driving to LA from Sacramento over the 4th weekend and will try 55MPH all the way. Going from 60 to 55 MPH on a 400 mile trip will only set me back about 36 minutes. If it saves me some $$$ I'll do it.

 

You'll be amazed what 5 mph slower will do for mpg's.