18.4 MPG!

nitroguy

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Just came to post that. I couldn't believe it. My first fill up was 16.5mpg, and I thought it was a fluke it was so high. Then the next tank yielded the impressive 18.4! My last truck, a 2002 Dodge ram 1500 would get 10.5, so I'm thrilled! I drive mostly country type roads with lots of slowing down for curves or stop signs then up to 60, then back down.
From what I can tell, the truck (Red Fred The Rusty Ol Flatbed) has 3.73 gears, 4sp transmission, and a na 6.9. I still need to change out my diff and tranny fluids too, which I can imagine will only help!

Long story short - goodness I love this truck! It inexplicably brings all kinds of joy and delight when I chug down the road.

Keep on trucking!

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Macrobb

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I'm honestly curious. It sure seems to me like 6.9s get better fuel economy than 7.3s do. They also seem to run smoother for some reason...
I wonder if it's due to the head design differences on 7.3 for emissions...

edit:
With a 7.3, turbo, 5-speed, GVOD, and 4.10s, the best I ever got was 18.5 on a straight highway trip of a full 8 hours or so, at 50-60MPH(so near perfect conditions).
 
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bbjordan

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I'm very happy with my 6.9. It got 8.6 km/l (20 miles per US gallon) on the last trip to the farm. That's with 4.10 gears, 305/70R16 tires, ZF-5 trans, in 2WD with hubs unlocked, and no fan on the engine. I travel at 100 - 110 km/hr (60 - 70 MPH).
Got lucky and had the wind at my back both ways. :)

Edit: that's running my WMO fuel cocktail: 85% WMO, 10% RUG, and 5% BioDiesel.
 

franklin2

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It's very difficult to get high mpg numbers with the latest fuel you can buy at the pump. They zapped it for emissions.
 

Thewespaul

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I typically average around 17 in the shop truck just running around empty in town, in a recent trip from Lubbock I got 23 mpg. That’s with no fan or filter and my other few mods.
 

Selahdoor

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Whats with no fan? Is no one concerned with engine overheating?
 

david85

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I first did the no fan mod years back. It works fine as long as you are at speed. For a few years, it became part of my seasonal routine to remove the fan for winter driving. Made a big difference in the warmup zone of the driving cycle because I was never able to get my fan clutch to stay unlocked when cold. Even after replacing it, the new one was even worse. I know it's burning extra fuel, but I don't have time to fiddle with it lately. I've long dreamed of an electric conversion but I don't have the time right now.
 

Selahdoor

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BTW: this is one of the reasons I am working to get my "new" truck on the road.

There is a problem with overdrive, in the E4od. But even with that problem, it supposedly gets 15mpg.

My other truck... 6 to 9 mpg if I am lucky...
 

Oledirtypearl86

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I pull a consistent 17 at 55mph with a crew cab long bed , F-350 with a t19 and a 6.9 till I get a out of Towner on my tail then I black them out till the turbo catches then I'm at a break neck speed of 65 or so
 

bbjordan

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Whats with no fan? Is no one concerned with engine overheating?

I'm not, but I live in Calgary Alberta, north of the 49th parallel. At my brother's farm, about 4 hours north, he had ice in the bird bath this morning! If I lived in Southern California or Texas I might be concerned.

I still have the winter front on my truck.

It depends on your situation. I mostly use my truck to haul stuff back and forth to the farm, so mostly highway travel. I've never had a problem, even towing one of my trucks to the farm!

The only time it has come close to overheating was getting stuck in rush hour traffic in the city: stop & go traffic.

A couple winters ago, I was picking up an engine for my brother, and left my truck truck running because it was -30C out. After BS'ing with the guy for 10 -15 minutes I realized I had left my truck running. I ran out expecting it to have overheated. Nope. It actually lost heat and had cooled down! That is how efficiently the 7.3 PowerStroke runs at idle.

I figure there's a couple of advantages to not running a fan.
1. Increased fuel mileage due to less HP robbed.
2. Longer water pump life due to not having a big weight wobbling around on the front of the pump shaft.

Of course, overheating the engine can ruin your day, so plan B is to open the windows and turn on the heater full blast. It's no fun, but I'd do that for my truck. In fact, I have done that. :)
 

Thewespaul

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I live in south Texas and dont run a fan, Ive got the cooling mod done to this engine (and all my engines) and dont have an temperature issues. If I sit idling for 20-30 minutes idling in traffic in 100* temp coolant temp will come up to 220, but I as soon as I start moving or bring rpms up the temp comes back down.
 
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