Turbo v non-turbo mileage?

[Selahdoor]

Installed Banks kit in '87 when the truck had 7K miles on it. Slight uptick in mpg for the same driving style. Where the turbo shines is the power department and the work you get out of a galling of fuel. I noticed that under load the truck deliver better mpg because you didn't have to have your foot in it quite so far. Also, by adding more air to a given amount of fuel (controlled by the pump) you get more complete combustion so you are getting more work from the fuel. Getting near 30 years of ownership of this truck and the mileage is as predictable as gravity for the most part. It's very rpm and gearing related, whether turbocharged or not, so if a person is wondering where to spend money the most wisely to get mpg, a 5-speed conversion is probably the best choice.

That is the conclusion that I have been coming to. Trans swap will do the most. With a change of gear ratio being next. (But with 4x4, you have to change gears to match front and rear, so more costly than 2wd.


My last fillup showed my mileage to be 8.4.

 

[Pullet]

I should probably post an introduction instead of resurrecting this thread, but maybe I'll manage to be introductory and redemptive. I've been reading here for a while, and have to chime in here..

I'm a miser, a hypermiler who has ridden far enough on a bicycle to sympathize with the machinery that moves me, and when I first got a '90 f250 7.3 IDI I was seeing 22-24 mpg depending on how much highway driving and how many hills. It (The White Buffalo) was 2wd 4spd auto, srw, reg cab, power nothing, with a/c, and it would idle along happily whether loaded or empty, at about 1300-1800 rpm for me, getting its worst mileage empty on twisty mountain hairpins in norcal, 13-15mpg (a/c running). That poor truck had been run down as a (family) construction company truck until the tweaker (son) I bought it from inherited it from the company and bumped a bimmer with it, but the engine chugged dependably along despite nothing else on the whole truck showing any sign of ever having been maintained, repaired, or replaced.
It moved me and everything my wife and I owned, from CA to WI, and I averaged 23 mpg at ~55mph indicated, ~50 actual, right in the steep part of its torque curve, and the slow end of the slow lane. In WI it moved supersacks of grain, 2-5k# at a time, around the hills and farms of the SW corner of the state, getting 17-19mpg until I found its replacement.
It wasn't good at starting below freezing, and 2wd made getting firewood off my hill take extra time, and then I got stuck after unloading at one snowed-in farm...
So I found Pullet, a frankentruck '90 7.3 idi f250 reg cab 4wd zf5 srw with a cushion bumper sitting on 35s (since removed) with a straightpipe out the side and a gooseneck hitch. A/c deleted, cruise control steering wheel and fancy radio added.
It's been getting about 14mpg, except when I was getting firewood in LR4wd, when it got 4.5mpg.. but I was hitching to bigger and bigger chunks of trees and still upshifting. I've got some questions for y'all about its quirks, but it just came to New York weighing and pulling many tons and getting 10-12mpg. Speed was not impressive, but the (massive) job got done and everybody lived.. and now I'm tempted by a turbo all over again..
Engine is stock, but it smokes grey on startup and black if I floor it towards redline, but that's rare, I'm cheap and usually not in any hurry. Seems like a tiny turbo could help me keep speed and be less of an obstacle to others whilst also getting me nicer mileage, just has to kick in at low revs or I'll (almost) never get use from it.

Anyway, (TL/DR: ) I've gotten 25mpg on a tank with (IIRC) 2.3 final gears and 4sp auto 2wd, and that truck got 20+ most of the time, without fancy parts I wanted like overdrive. Now I'm turning 4.10 zf5 4wd and seeing low teens, but everyone looks as I rumble into sight or roar through snow.

 

[no mufflers]

well, from my experience I have never gotten under 10mpg towing. that was with a 8,000lbs trailer. on the highway I can get 16mpg on a good day but an average I will get is 14mpg. my truck weights 8,500 dry and all the details on it are in my sig.

 

[Macrobb]

I hate to say it, but timing timing timing.
When you are using unknown or known used IPs and injectors, timing becomes a real factor.
If you install *new* parts(either or both), you've got to re-time it.
And being just a couple degrees off will definitely hurt your fuel economy and power.

Seriously - if you are looking for good economy, make sure your fuel system is in good shape and everything's timed correctly.
Even a 'by-ear' timing job will net you a far better running truck than doing nothing.

Personally, my last tank in my '93(F-250 4x4 Ext. cab, ZF-5, factory turbo with 110CC IP and 250 HP at the wheels) was 15.6 over about 16 gallons.
This included daily commutes(10 miles one way from cold start, mostly highway), as well as about 100 miles of 65-75 highway driving -- I'm not a hypermiler and go as fast as I can to get where I'm going.
There was also a few miles of hauling a load of refrigerators in there(upright), which definitely lowers the aerodynamics of my truck...

Anyway, if I can maintain 15.6 while racing around with a big IP, 4x4 etc... That should be easy for a hypermiler or someone who /tries/ to go slow.

 

[jwalterus]

There was also a few miles of hauling a load of refrigerators in there(upright), which definitely lowers the aerodynamics of my truck...

There we go!
You just answered the age-old question: "How do you lower the aerodynamics of a brick??"