looking for F250 gas mileage examples

[2PNPOD]

I'm a newbie here. I've been reading this forum for about a week. This place is great, I've already learned a ton thanks to everyone.

My husband and I are searching for the right airstream. We haven't decided whether or not to by used or new. We've been in all of the A/S at Traveland, and are thinking of going to iowaboys this weekend to view some vintage units.

It'll be just the two of us and our Shih-tzu, so we're looking for a small airstream. I want the Bambi, but my husband (6'2 at 210) wants something a little larger. I'm willing to go as large as 25'.

We have a 1992 F250 7.3L longbed 4x4, which gets 10 to 12 mpg. I'm sure this can be attributed to the 6" lift and larger (though not HUGE) tires.

I'm wondering what the gas mileage would be if we actually towed something, and thought I'd see if any other F250 owners could give me an idea what to expect. Like should we be looking for a new tow vehicle as well as an A/S.

Thanks for all your support!

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blamejane

[flyfisher]

Is your Ford a diesel? I have a 2000 F250 deisel, 7.3L long bed, 4X4 with a cap on the back, and with whatever the biggest tires Ford offered - I think they're 265X16, but I'd have to look to be sure.

Towing about 7000# (with a heavy foot at times) I get between 10-12mpg, and when not towing get about 17-18mpg highway.

Sometimes I think my wife is dragging her feet a bit, but that's a different story! *G*

John

[ipso_facto]

We have a 1992 F250 7.3L longbed 4x4, which gets 10 to 12 mpg. I'm sure this can be attributed to the 6" lift and larger (though not HUGE) tires.


Hm, you should be doing better than that. This is 460 gas motor territory. I get that in my F250 and it is only 2 years older than yours. Especially given that it is a base F250, not a "heavy duty" which is different from "base" F250. As for tires, larger tires should lower your RPMs, resulting in a better mileage when empty. (See http://www.ring-pinion.com/calculators.shtml )

You consider using the standard tires that came with it, to keep the default 3.73 rear axle ratio for this diesel engine. I thought about getting a different rear end for my truck (go from 4.10 to 3.73 or even 3.55) until someone told me that 460cid engine needs 4.10 rear. It is something about it getting its max torque/HP at higher RPMs. Your diesel didn't even come with anything lower than 3.73.

If you have overdrive in your transmission, you should definitely be doing better than that. I am not a diesel person (in fact, I don't know that much about gas trucks) but it seems something is wrong. I hear the standard things to try are:
Oxygen sensor
fuel filter
Spark plugs and wires
Basically a tune up.

[2PNPOD]

Hey flyfisher, thanks for responding.

Our F250 is not a diesel. I think it's actually a 7.5L; sorry about that.

Anyway, if we're only getting 10 to 12 on the highway, what's it going to be like when we tow? From what I've been reading on this forum, looks like we'll lose 2 to 4 mpg. That seems crazy to me.

[2PNPOD]

ipso_facto thanks for all of your info. I was mistaken when saying we have a 7.3L. What we have is the 460/7.5L you described (I think).

[ipso_facto]

What we have is the 460/7.5L you described .....


Then that mileage is perfectly normal. That's what I am getting. (And seemingly everyone else with 460) I am almost certain you have the 4.10 rear axle. All F250 460s got it unless you special-ordered a 3.55 - and you don't want a 3.55. Do you have the old C-6 tranny (3-speed) or that newer E4OD which is like C6 with overdrive?

To find out what tranny you have, look on the sticker on the side of driver's door. At least that's where mine is. There are all these codes which tell you which tranny, rear axle, etc. Post them and someone will decrypt them for you.

In any case, lots of electrons have been used discussing 460 mileage improvement. Not much optimism there. The key is to keep your RPMs down. Around 2500 if you can. At 65, I am turning 3100 rpms and that reduces my mileage to 10.5. If I reduce the RPMs to 2500, I get 11 and 3/4 and I think I could get 12 if the RPMs were 2200. With overdrive, you should reduce your RPMs.

Towing 6300lbs, at 3000 rpms, I get about 8.5 MPG. Slowing down to 2600 RPMs, I get almost 10. Do you have dual tanks? You pretty much need them to extend your range beyond 170 miles.

[uwe]

blamejane,

I would not expect miracles in mileage from any vehicle when you're towing. i get about 8or 9mpg when I tow my 25ft Airstream, with very few exceptions. My usual mileage is between 11 and 13.5mpg.
I think it's more economical to keep the gas hog and pack extra cash, then buying a new tow truck for 2 more mpg, unless you plan on towing 50ooo miles a year.
Of all my friends that tow, only one gets decent mileage. He tows a 28ft or so toybox with a Dodge Diesel. He gets between 13 and 15 mpg towing this huge white thing with dirt bikes and gear in it. His truck has the Cummings turbo diesel in it. It sounds like a can with nails in it, but it pulls reeally hard and apparently gets good mileage doing so.
Good luck in your search. PM me if you want to check out my trailer and van combo. Orange is not far from you.

[59toaster]

I'm really surprised you feel you need to turn so many RPMS to be in the power band of the 460. That's the sort of gearing I would expect for a smaller V8 like a 350 or a 360 ford. My Suburban has 3.73 gears and 235/15x16 tires. I don't run it past 65mph since it predates Overdrive and I'm turning abut 2800. I'm still seeing what sort of MPG to expect empty.
Peak Torque on this motor is 385pound feet at 1600 RPM. I would think a 460 would be close to the same.

[j54mark]

59toaster,

You don't need so many rpms for the 460 power band. That is precisely the problem with the gas milage. With a 4.10 rear end they have to turn high rpms to run highway speeds. Never was an engine in such need of a really strong overdrive.

On the other hand, when towing or hauling a load that huge displacement and a 4.10 is one potent combination.

They used to put those monsters in sedans - Lincolns and such - with high gearing and they were far more economical.

Mark

[2PNPOD]

ipso_facto: Yes, we have the dual tanks. I'm not sure about the tranny, but I'll check the sticker; thanks for the tip.

uwe: I agree with you and now feel pretty good about keeping our truck. Glad to hear we're not alone.

j54mark: Sounds like our truck will definitely do the job.

Thanks to everyone for taking the time to answer my post. Now, if I could just find our airstream. I'm off to check eBay, rvtraderonline, airstream.net,...

Blamejane

[ipso_facto]

Looking at the horsepower and torque chart, they intersect at 2800 rpms. So if you want good mileage, that's the rpms to use, anything faster lowers mileage. In terms of speed, 2800 rpms = 55-57 mph.


Your mileage is appropriate for your engine, but FWIW How to improve 460 mileage

[2PNPOD]

ipso_facto: Thanks, great thread; which I just finished reading.

This place is great!

[ipso_facto]

blamejane,

I agree. Just a few short months ago, I knew nothing about trucks/RVs.
Now I know more about GCWR and rear axle ratio and cubic inches and torque and horsepower and O2 sensors (and whatever else pertinent to the issue) than I ever thought I would. Which is still less than what some on here have forgotten.
Undoubtedly, I am indebted to forums like this one and a lot of R/L help, too. I don't think I could have made it without lots of help, at the right time, in the right place.