fuel econ/mpg

[Sri Ram]

Last weekend I filled the tank on my 91. Since I had some fuel in there already, it took only 20gal. I drove about 220mi, all at 60-75mph. When I got back it took 21gal to fill it again. I wasn't towing, but I did have 1000lbs of stuff/passengers/etc. , tailgate up. Is this the correct mpg?

 

[JLEONARD]

Hey... you gotta do the math first, then ask.

Shheeesh... what do you think we are math majors or something? :-laf



Ok. my calculations say that's 10. 4 mpg.

That's kind of horrible mileage. I get more than double that even if I'm hammering on it and doing 75/80 with 500 # in the bed for traction.

Something's awry.



Tailgate up is the best anyway. There have been recent studies that prove that, PLUS... Mythbusters proved it too.





Jay

EDIT. . I see you have 4. 10s. . I have 3. 54s... but that still an awfull lot of difference.

 

[ScottLowry]

Running 60-65 I get 18 empty and 14 with 6k on the truck. I have a 92 1-ton 5-speed 4. 10 gears straight pipe. I get 11 fully loaded That is 6k in bed and towing another 12k or so. I think you have an issue somewhere.



Scott

 

[Sri Ram]

Whoops, I thought I had edited that part, too. I'm not a math major OR an englich major!:-laf The total mileage was 440, so the mpg was almost 21mpg. I know that's not bad, but I wanted to start a thread about economy anyway. Ditto on the tailgate up. I made the same trip with the gate removed and the mpg was around 15!



I know we can make more power in these trucks. And sometimes the same mods that create more power also improve fuel economy. But, what mods can we make purely to improve our mpg?

 

[TKingsbury]

I got 21 mpg with my truck on mostly freeway keeping it under 70mph. Put a few hundred miles on it last week, all freeway going between 70 and 80 (mostly 75ish) and got just over 19. Normal everyday to and fro gets me 18.

Travis. .

 

[91W350]

My old 91. 5 D250 would get in the 20's pretty regularly. This W350 seldom gets over 21, normally around 18. It s pretty tall though and a rolling wedge, nose up attitude. I think adding an inch to the rear to level it and removing the huge mud flaps will help. My W250 does about the same, only it is a club or extended cab. They both have the 3. 5 gear.

 

[TomThomas]

funny this should be brought up. seems like i'm gettin 13-15 around town, 17-19 hwy (all empty). Typical? Thinkin it may be time to look into injectors (at 330,000 miles). I had a Navistar (f*rd) once, and after Stanadyne performance formula and straight pipes it got 3mpg's better. But after spending a total of $7k on the transmission, it didn't really matter what it got for mpg's. :{

 

[JLEONARD]

But, what mods can we make purely to improve our mpg

Someone in here once said "tape a pine cone to the accelerator and drive barefoot"

Seriously the weight of your right foot will control mileage as much as it can be controlled.

Generally speaking the "typical" mods most of us do won't adversely affect mileage unless you use the power.

For example I can still get the same mileage if I drive lightfooted... if not I get maybe 1 or 2 mpg less.

 

[91W350]

I know my worst tank empty on the W350 was right after I fixed the EGT gauge, just had to see how it responded! I have noticed that running over 70 is expensive and over 80 is much worse, the Kansas Highway Patrol has kept me from trying a tank at 90. I would hate to be involved in one of those :-{} roadside conversations. :-laf Glen

 

[Sri Ram]

JLEONARD: That is what I expected to hear. And, it's also encouraging. Wind resistance quadruples every time speed doubles, right? So, if we go a little slower…(sacreligious, I know).

Most folks look at my trucks and think 10mpg max. They're surprised when I tell them the truth, that my boxey pickup gets better economy than their SUV! I guess it's just ignorance about diesels?

I'm just curious if anyone has been able to push that 19-22mpg even higher.

 

[91W350]

My 91. 5 D250 would roll up into the mid 20s, I think 26. 7 was the best at 55. 55 sucks though, good thing it had cruise, or I would have been running with traffic, regardless! I think it was pretty much all stock, with the exception of the muffler delete option being selected on the build sheet. I have not been close to that with a 4x4 yet. I need a huge tail wind... Glen

 

[PAddington]

JLEONARD: That is what I expected to hear. And, it's also encouraging. Wind resistance quadruples every time speed doubles, right? So, if we go a little slower…(sacreligious, I know).

Most folks look at my trucks and think 10mpg max. They're surprised when I tell them the truth, that my boxey pickup gets better economy than their SUV! I guess it's just ignorance about diesels?

I'm just curious if anyone has been able to push that 19-22mpg even higher.

When I had the 3-speed I would get 22mpg at 65mph, and about 20mpg at 70mph. With the 47rh I get 24+ at 70-72mph and at about 77 I get 23. Remember all of this is with 3. 07 rear gears.

 

[Chris and Sam]

I get low 20's mpst of the time, and high teen pulling a car trailer. best mileage in my W200 crew cab in my sig was 26. 6 mpg on a trip in the summer doing about 70 mph!! gotta love the 1st gen trucks!!!

 

[JLEONARD]

I normally get 22/24 mpg. I have gotten 26+ on a trip driving at 70 max. But I don't often have the discipline for that. :-laf

 

[Sri Ram]

Those are some good numbers. Seems like gear ratio has the biggest effect on mpg?

 

[dpuckett]

Timing and AFC settings, in my experience, have the most effect on MPGs. COmbined with a steady right foot, of course. I have mine set to about 1. 7mm (upper limit for efficiency with stock injectors), and ahve a tight rein on the AFC spring. It'll still make the boost gauge jump, though. I have 4. 10 gears, duals, and a 5spd.



The 92 Green Guzzler got over 22 on our trip back- 60-65mph. It had been sitting for 6-8mo. It is a 4x2 Club cab dually with a 9ft steel flatbed. 3. 54 (tag says, anyway), 5spd. It is the "cheaper" truck of my two new ones- $750.



Daniel

 

[Sri Ram]

dpuckett: what are AFC settings?

 

[91W350]

Just got home from a 150 mile run with a stiff crosswind, ten gallons even, that is pretty easy to compute! It was pulling 5-10 pounds of boost most of the time. I drove a little harder than normal, I was running late getting to my son's ballgame. Just about a needle's width under 80 most of the way. (the W350) Glen

 

[backroad]

You guys and your wonderful mileage... . I can't stand it. I've got my '93 Cummins in a '87 Ford F350 4X4, crew cab, dually and all I can muster up is maybe 14 mpg. You don't even want to ask what it gets loaded. At least its better than the 8 or 9 my 460 gas motor used to get. I do know that my 35" tall rubber and 4. 10 gears have an adverse effect.

 

[91W350]

I do know that my 35" tall rubber and 4. 10 gears have an adverse effect.

Yep, you are pushing a sail across the desert...