Fuel mileage numbers?

[BrandonMag]

So I just put a little over 560 miles on my truck and I averaged 14.125 mpg. That was mostly cruising down the freeway at 58-60 mph unloaded with the AC on.

My truck has a Moose pump turned down two flats, Hypermax turbo, Delphi BBs, 4.10 axles, Toyo 315/75-16 MTs, a 2-inch body lift and a 1-1/2 inch front axle lift. I religiously change the engine oil every 3K miles, the tranny/transfer case fluid is fairly new, the front axle fluid was changed about a year and a half ago, and I just changed the rear axle fluid. The biggest drag on my fuel mileage that I can see at this point is that I'm running a locked fan. The clutch took a dump and it was a quick fix, I'd like to install electric fans but have not had the time.

There was some discussion about my fuel mileage in another thread, and I'm curious what other people are getting.

Any recommendations to improve mileage? As far as I can tell my fuel system doesn't have any major leaks, but my filter head does weep a little diesel once in awhile.

 

[JwS]

Hmmm, loose the lifts... fix the fan, changing ratios would probably help, but with 4x4 that is a big expense, and I actually didn't see a huge change going from 4:10s to 3:55 on my van...
I see 15-16 on the highway, just did a cross country trip, the mileage dropped a bit coming back towing 3000lbs on a trailer... but only down 1 or 2 i think... I have seen up to 19 unloaded and taking it easy.

 

[DesertBen44]

Unloaded I get 18 mpg all day 60/40 highway/city.

this is with a 1992 f250 4x4 5 speed manual, n/a (not for long! =P) w/4.10 gears. I rarely tow, and cant really give you a good number for my mileage towing because I was usually paying more attention to getting the trailer the hell out of intersections before crazy southwest drivers hit it.

I will admit I drive like a grandma usually; If i want to go fast my big old diesel is not my method of choice.

I am considering switching to a 3.73 type gear or maybe even 3.55 since I rarely tow, and it looks like the gf loves the maxima enough where I will be driving the truck daily, which I dont mind at all!

I run 285 tires I think- I would think with 4.10 gears you would do better with a larger tire, at least thats one of the main reasons I still have them, am hoping eventually to roll with a 4 inch lit and 35 inch street tires. Would think my rpms would be lower on the highway

 

[DesertBen44]

Just read over your post- there is your problem. MUD TERRAINS! Get a set of street tires and put on the mud terrains when your offroading! Waste of ride comfort and mpg imo. Even though nothing looks meaner then a nice set of MTs...

 

[tanman_2006]

The 315/75s are roughly a 35x12.5 tire so i would stick with 4.10's. Tire size and weight it limiting you as well as the fan and lift. 14mpg sounds fine for your set up.

 

[Can30Diesel]

I get about 17mpg on the back roads, unloaded and driving like an old man. On the hwy I get about 12mpg doing about 60-65mph wound out to about 2500rpm also unloaded. Loaded or pulling a 5600lb trailer I lose maybe 2mpg on both hwy and back roads.

I am running a 6.9 N/A with 410's, 4 spd T19, 285 (approx 33 inch) mud terrains on aluminium rims , 3 inch body lift and 3 inch suspension lift. In my case, I will eventually be moving to 35 inch tires and a 5 spd ZF, but thats just time and money away.

 

[chevytaHOE5674]

How are you calculating mileage? Has the odometer been corrected for the larger tires?

 

[Dieselcrawler]

My dually gets 16-18 on the highway. Got 12.3 towing the crawler home from the rally. 5 speed dually with 4.10 and 245 70 tires. Also moose pumped and bb codes. Timed to 9.3

 

[Devon Harley]

285/75/16 4:10 I get 16 driving 70

 

[Hyde]

N/A 6.9, T19, 3.55s, 35x12.5 BFG mud terrains, I get 16 at 70-75, I lost .5 mpg with the 35s from my 265/70/18s. Turbo install is planned for the weekend after Labor day, will update then. Also thats with the odometer on my GPS since the speedo quit.

 

[SparkandFire]

I get a solid 16 mpg average in my truck, 80/20 highway/city driving and climbing Hwy 17 every day...

http://en.wikipedia.org/wiki/California_State_Route_17

I do have skinny little tires, though.

What is your timing set to? That has a noticeable affect on fuel consumption. Fuel quality does too. I doubt there is any low-hanging fruit when it comes to fuel economization on these trucks. Its a lot of little, cumulative improvements that add up.

http://www.eurojournals.com/EJSR_59_3_14.pdf

 

[Black dawg]

I really dont think the tires or the fan should make a big difference. I am also curious as to to accuracy of your odometer.

 

[Hydro-idi]

With hydrogen injection turned on, I've been seeing between 19 and 20 MPG on highway doing 60 MPH. Rpms stay at 2600 at this speed. Lately I've been running diesel fuel as well.

 

[flareside_thun]

The more I read this, the more irritated I get....I usually get 11 city no matter how I drive it. I know I'm well due for an IP and a set of injectors(plus I could use a return line kit) but geez. $4.19/gallon sure does hurt.

 

[FordGuy100]

15mpg at 70

18-19 mpg at 60