Fuel mileage

JAKRANCH · Nov 3, 2017

I was reading somewhere about a guy that claimed to be getting high 20s to low 30s fuel mileage on a t 19 with 6.9. I have 3.55s and the best I've ever got was 21! What would you jave to do to male insane mileage like that?

lotzagoodstuff · Nov 3, 2017

Lie about your mileage!

Macrobb · Nov 4, 2017

Pretty much lie about it. Unless you, say, run 50% wmo/wvo and only count the diesel in your fuel calcs...

I average 14-16 unloaded. Best I've ever gotten was 18 on a long trip with a lot of 60 mph roads, with my '88 - turbo, 5-speed, 4x4, 4.10 gearing amd a gearvendor overdrive.

jayro88 · Nov 4, 2017

Didn't someone swap a 6.9 into an F-150. The lighter weight, along with quite a few eco mods netted some impressive numbers.

To the OP...21 mpg is good. Do you also have a t-19? If so, swapping to a zf-5 could net you a little due to the OD. Your driving habits can change a lot. Hwy cruising speed, coasting in neutral much as possible. Some people go as far as turning the engine off and coasting as well.....but this can effect your brakes and steering.

I posted a thread a while back about an experiment I did in my E250 regarding hwy cruising speed vs mpg. Having a well maintained rig/fueling system is big. I have about 120k miles on my IP/injectors and have been seeing a decline in my mileage.

jayro88 · Nov 4, 2017

Here is my thread I mentioned.

https://www.oilburners.net/threads/my-speed-vs-mpg-experiement.70693/

JAKRANCH · Nov 4, 2017

Actually in process of swapping in a zf 5

. Long thanksgiving trip I'm excited to see some big improvements!

Thewespaul · Nov 4, 2017

There was a guy that got that good of mileage I remember, he was in a half ton with an overdrive unit and a bunch fuel pincher mods like auto shutoff when sitting at lights and so on...

jayro88 · Nov 4, 2017

JAKRANCH said:
Actually in process of swapping in a zf 5. Long thanksgiving trip I'm excited to see some big improvements!

Hope it works out. When I added the DNE2 OD to my c6 the biggest improvement I saw was in my average mpg. My peak moved up some, but i consistantly saw mileage closer to my peak. My IP is getting worn, but I still rarely see below 15mpg. Prior to adding the OD I Would see 13s on a fairly regilar basis if i didn't drive nice. Still have yet to hit 20mpg. May be put of reach for my c6. Definitly doable if I had an e4od or manual.

Hydro-idi · Nov 4, 2017

Sold my truck to father in law a while ago but he’s getting a consistent 18-19mpg empty cruising down highway. Rebuilt n/a 6.9 & C6 with 3.08’s in rear end.

chris142 · Nov 4, 2017

12 in town and 14hwy here

jwalterus · Nov 4, 2017

JAKRANCH said:
I was reading somewhere about a guy that claimed to be getting high 20s to low 30s fuel mileage on a t 19 with 6.9. I have 3.55s and the best I've ever got was 21! What would you jave to do to male insane mileage like that?

I quoted myself for my mileage from a few years ago:

jwalterus said:
in the flood victim on different fuels I get the following:
#2 w/PS: 14.7town, 22.3hwy
#2 /Howes: 14.5town, 21.7hwy
#2 w/o PS: 14.5town, 20.1hwy
#1 w/PS: 12.1town, 17.3hwy
P-40 diesel: 14.5town, 20.7hwy

I'm down to 13/20 on #2 w/PS this year, but I'm due for injectors and an IP soon, and contemplating a complete overhaul just because.....

Coupla threads on the subject of mileage:
https://www.oilburners.net/threads/idi-mpg.78476/
https://www.oilburners.net/threads/mileage-vs-rpm-vs-gear-ratio.62592/#post728681

snicklas · Nov 4, 2017

The only truck i have know to get mileage pushing 30 is Matthias Agne (Mel's son) swapped a 6.9/ZF-5 into an OBS Half-ton stepside, the truck originally had a 300 inch six in it. I think it has the 2.something or 3 something 8.8 or 9 inch Ford in it..... basically they pulled the blown head gasket 300 out, and plopped a 6.9 in it... and modded the gasser core support for a diesel radiator....

That is the truck you see on here called The Night Moose

https://www.oilburners.net/threads/moose-fleet-rally-mpg-results.32371/

bbjordan · Nov 4, 2017

This is extreme, but shows what is possible. He is also losing ~9% because of the lower energy content of biodiesel.

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Keeping your top speed low and proactive driving can make a big difference.

Fuel mileage

JAKRANCH

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lotzagoodstuff

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Macrobb

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jayro88

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jayro88

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JAKRANCH

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Thewespaul

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jayro88

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Hydro-idi

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chris142

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jwalterus

Made in America

snicklas

6.0 and Loving It!!

bbjordan

Snow Monkey

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