Miles Per Gallon for a 7.3L?

[dave_parks]

I own a 1991 F-250 extended cab with a non-turbo 7.3L diesel. Since buying it in 2004 we've got a high of 15 mpg to a low of 10 mpg--whiel towing our 25 ft. fifth wheel. I'm hearing from a friend of mine, who has heard through other diesel owners, that my mpg is low. I'd love to get more mpg if at all possible, but what is a realist figured for mpg. One last word. I did upgrade the exhaust, but that didn't influence the mpg one way or the other. [img]/ubbthreads/images/graemlins/confused.gif[/img]

[wbones9]

thats about what i get, which is normal for a NA diesel. The turbos will genereally get a little better mpg.

[Mike Lewis]

15mpg while pulling a 25 foot TT?

Wow! I'd say you're doing pretty well!! I've gotten about 13 pulling a 30' 3-horse/extended tack trailer at about 8000 pounds. 15 would be halfway to heaven.

[shorthair]

mt for daily use 17-19 towing my 31' TT 12 mpg here in the NW.

[d9d]

howdy guys,

Might as well introduce myself in this thread; as I'm concerned with MPG too.

I've been hanging out over with the 6.9 guys for a couple years; since I have an '86 F350 4x4. Just drove home a 1991 F350 4x4 last night; so I guess I'll have to stand with one foot in each forum from now on...

Anyway, for the past year, I've averaged 18.4 mpg on trips with the '86 6.9. Probably about 500 lbs total in the bed (crossbed toolbox, spare, 100 lbs of hand tools, plus misc-junk of course...). The 6.9 has 3.54 axles, T19 4spd, and 265/75 tires. On the '86, I usually cruised at 60mph...sometimes 65 for a bit; but generally kept it mellow at 60.

This 'new' 1991 is a 7.3 of course, and the 5spd, and has 4.10 axles and 285/75 tires. It runs the same or slightly lower RPM's for the same cruising speed. Around 2,000 rpm for 60mph.

When I got home, I was quite disappointed to see that I probably only got 12mpg or so. I won't know exactly until I top off the tank again. But if the gauge is at all accurate and linear, then the MPG wasn't very good. 3/4 of a tank in 182 miles.

This 1991 seems to love going 65-70, so I ended up cruising that speed most of the way home. So that probably accounts for at least 2-3 mpg; just from increased wind-resistance loss. The wider tires probably eat a bit as well. But 15 mpg unloaded still seems kinda poor to me.

ps; both trucks are non-turbo.

In any case, I look forward to learning more from y'all about these newfangled 7.3 IDI trucks...

Richard (D9-D)

[V2Neal]

My '90 F250 extra cab 4x4 full topper with about 300lbs in the bed (work equipment) averages 14mpg around town and 14mpg at 70 on the highway. I did manage 17 once, but that was cruising 2 lane at a constant 55-60. It seems to have smallish exhaust on it (2in) so maybe freeing that up and doing a soup bowl-ectomy would get me 1 more mpg. Either way it's better than I got with my Avy. Come to think of it, my friends 04 F150 extra cab 5.4L only got 14mpg with two motorcycles on a light aluminum trailer. I don't feel so bad about my "old" truck.

[yaric008]

In the city, i now average about 15 MPG. I used to get better, like up around 17 but then it just kinda dropped to 15. On the highway, not towing, and running about 60MPH i can get almost 20MPG.

[JeffW77]

I bought a 1990 E-350 van in January. 7.3L IDI engine, E4OD tranny. I get 17 mpg in daily driving. I drive gently. Hoping to modify for greater mileage.

Jeff Wilson
Portland, Oregon

[d9d]

yah, the speed really makes a difference. I've seen that repeatedly in our Jeep, which has a real-time MPG-avg display. Steady 60 runs 20-21mpg, whereas a steady 70 drops it to 19, and a steady 78 drops it to 18.

The speed/air-resistance effect has gotta be even worse on our flying-bricks...

I filled that tank today, and now know that I used 14.38 gallons to go 209 miles....so, 14.5 mpg. Not real good for an empty box and all-freeway.

But again, that was mostly 65-70, with numerious 1500' climbs through passes (I-5 between Eugene and Grants Pass).

This truck is ALL bone stock. All service done at the Ford dealer. So it must have a 2.5" exhaust. I haven't even looked yet. And no ram-air like my '86, of course.

And I think the pump's a bit retarded. Pretty quiet motor....too quiet maybe.

Perhaps with 3" exhaust and a bit of IP advance, I can get back to 18 or better....but probably only if I keep it to 65...

[jminix]

I have a 94 F250 4x4 super cab long bed with a IDI TD, E40D, 4.10 gears 235/85/16 tires at 80psi. The truck had 122k miles at the start of the trip and a bit over 123k at the end. I drove it back from FL and tested the mileage. Here is what I got...the truck was basically empty...one motorcycle in the bed and pulling a jet ski on a trailer.

Cruise Control set at 70mph (about 2250rpm) --> 13mpg

Cruise Control set at 60mph (about 2000rpm) --> 16.5mpg

Cruise Control set at 55mph (about 1800rpm) --> 21.3mpg

All of the above figures are indicated (as opposed to GPS confirmed etc) and were obtained in very similar moderately hilly conditions on the same day and were tested for more than 100 miles.

[dorton350]

I run 65-70 and get 14mpg. I think I want to get GV unit. Just need someone to buy it for my birthday. [img]/ubbthreads/images/graemlins/grin.gif[/img]Then maybe I could get around 20 now that would be cool. [img]/ubbthreads/images/graemlins/smokin.gif[/img] Wayne

[agnem]

[ QUOTE ]
so I guess I'll have to stand with one foot in each forum from now on

[/ QUOTE ]

You were supposed to be doing that all along. [img]/ubbthreads/images/graemlins/smirk.gif[/img]

We got 14.4 MPG going to the IDI Weekend last year with the Lady Moose, which I thought was pretty good towing a 30' 5'er. I'll have the GV unit under it this year, and I hope to see 18 with it.

[dbarilow]

daily driving I get 18 mpg

[d9d]

[ QUOTE ]
[ QUOTE ]
so I guess I'll have to stand with one foot in each forum from now on

[/ QUOTE ]

You were supposed to be doing that all along. [img]/ubbthreads/images/graemlins/smirk.gif[/img]


[/ QUOTE ]


hee hee...

howdy Mel !

That's pretty good mpg towing a big trailer!

I've got to remember to change my sig now...add the '91 info.

Sounds like my 14.5 mpg wasn't too bad then; although it's a lot less than my goal. Well, time to start working on the new girl then, right? Right!

[Bigsturg]

I get roughly 16mpg empty.
4:10's and 35's 16.5 rims 5 speed and a HEAVY foot.
This is about the same MPG as my sport trac...
not bad for a 1 ton
[img]/ubbthreads/images/graemlins/smokin.gif[/img]