Last Monday I drove from Challis, ID to Kuna, ID and got 22.8 mpg!

 

It's overall downhill but there are 2 descent grades to climb as well. 

 

My previous best was 21.5 and I've only broken 20 2 or 3 times. Normally mid 19's is excellent for this truck. It's heavy and has plenty of things to induce drag. 

 

I got full on the refill so I don't think it's a big error, and I'll have another change to try and duplicate it this fall. I did get 19.4 going the longer route two weeks ago and all of that was above 70 so it does check based on the slower speed of the shorter, but curvy, route. Avg speed for the tank was 47.0.

 

I took the pic while it was in my shop getting the oil changed, so there is even 5-10 minutes of excess idling on the tank. 

 

I've been tweaking my cruise timing but that's a bigger jump than anticipated but I'll take it. Bed was full of crap, to include a XL dog crate, there were all above the bed rails. I was all of 9,500 lbs and have my winter 33" mud tires on too. 

 

 

Impressive... 

I do like that, I have only made north of 20 a few times with 22.4 being my best.

that's awesome!!!

 congrats.

my personal best is 20.1 heading to Vegas for the weekend.

i can hardly wait to learn more on this tuning adventure.

So much for a retest....

 

I did the same trip but I started with a descent percentage of #1 in the tank and a little cetane boost, both of which lower mpgs. I also did the first 80 miles with a 30 mph head wind. 

 

Even with all of that it looks like I got 20.5 ± 0.5, based on fuel level and overhead standard error (yes, I'm the nerd who averages his overhead error). I didn't have time to top off and hand calc prior to running other errands and such. 

 

Quite happy!

I used to get 20+mpg quite regularly with MightyWhitey.  My best was 23.x IIRC..............twas 100*F+ with a light South wind, and I was traveling North.  Running the 265AC on that trip, as it wasn't humid because of the drought.

 

 

36 minutes ago, dorkweed said:

I used to get 20+mpg quite regularly with MightyWhitey.  My best was 23.x IIRC..............twas 100*F+ with a light South wind, and I was traveling North.  Running the 265AC on that trip, as it wasn't humid because of the drought.

 

 

 

Yeah you did pretty good. IIRC Mighty Whitey was a lot lighter and more aero dynamic. 

1 hour ago, AH64ID said:

 

Yeah you did pretty good. IIRC Mighty Whitey was a lot lighter and more aero dynamic. 

 

 

A lot "lighter and aerodynamic"???  We had essentially the same truck.  "Splain please.

Edited November 1, 20177 yr by dorkweed

1 minute ago, dorkweed said:

 

 

A lot "lighter and aerodynamic"???  We had essentially the same truck.  "Splain please.

 

You had a short bed right? 

 

With me in the truck, the bed empty, but with a tool box full of normal stuff, and full fuel it was 8400lbs which is heavier than most. 

 

My fender flares, running board, tool box, front hitch, and level kit all take fuel to run down the road at 70... all things I don't recall you having had on MW, but I could be suffering from memory loss. I looked but can't find any pics of the ol girl. 

I have found that I get the best fuel economy at around 45 to 50 mph but in this day and age, driving that slow is now a safety hazard since even the slow pokes drive 65 - 70 around my area.  To use the left lane and not have people up on your butt, you have to drive at least 80 mph and sometimes people are doing 90.  

 

Driving 45 mph on the Fort Campbell manuever reservation when you could drive through there which basically had no traffic, I regularly got 24 to 25 mpg and on my best run totally empty during Summer got slightly over 26 mpg.  My fuel economy drops like a Simonized piano once I pick up the speed and gradually goes down to around 12 to 14 mpg driving 75 - 80 or above.  Our trucks are not exactly the most aerodynamic vehicles on the road and aerodynamic drag is squared as you double your speed.  It is a HUGE drop from 45 mph to 85 mph.  

 

Nowadays, I just take it easy on my old girl.  Still got my 2002 just as it is in my signature.  She is almost 16 years old.  Around local driving I get 17 - 19 mpg.  On the highway, I still get 20 - 23 mpg depending on how fast I drive, what, and how much weight I am hauling.  She has been a good ole' truck.......God willing........I think I'll keeper another 16 years.  

Good work!!

IIRC;  I was running around 8100lbs. with my normal stuff and me in MightyWhitey.

Great work, pal

I have had a hand full of really good tanks over the years of driving my third gen. On one trip driving to Florida In January I got a couple of tanks that were way above normal.

 

Got a picture of one that provided 460+ miles to the half tank level and one with 200+ miles just getting off the fuel tank gauge post.

 

On other trips I thought I should have gotten more than I actually did and I can't always tell why either one of these conditions occurred (even when I'm trying to drive for good mpg's).

 

I start with a little more fuel on board than most.  My tank holds 37 gallons of fuel (I have relocated the vent tap at the highest point on the stock tank) so this allows me to fill my tank faster and allows me to put more fuel into it.

On 2/11/2018 at 7:59 AM, War Eagle said:

My tank holds 37 gallons of fuel (I have relocated the vent tap at the highest point on the stock tank) so this allows me to fill my tank faster and allows me to put more fuel into it.

 

 

Did you drill a new vent hole or just extended it?

You drill a new vent hole in the tank at the high spot. Then install a new bulk head fitting and then run the vent hose from the new bulk head fitting up to the fill spout and connect it to the place where the stock vent hose connected.  I just took the stock vent hose and shortened it and the plugged it off and just zip tied it to the filler neck so it doesn't bounce around or dangle.  The other end of the stock vent hose is still connected to the stock vent location on the tank. I didn't have any better way to seal off and abandon the original vent hole in the tank.

 

Obviously you need to drop the tank to do this mod, so you'll have a few hours tied up in this project.