Guys, I cannot figure this out!!!
You can see my truck info in my sig. How the hell is everyone else getting 19-20 mpg with the same truck set-up! I am going to go with a larger exhaust and a higher flow intake of some type. It's not my driving habits that causes it either. For goodness sake, I drive like a 90 year old woman trying to max my MPG. I am so @#$%&* about this. At best I am at 16.5. What gives? Is their that much difference between 6.0 and 7.3? Ideas and input PLEASE!

David

 

well I have the 6.0 and If I get 17 it is a miracle.

 

no clue for you issues. when mine was bone stock i didn't know yet to keep the speed under 70 and 2000 rpm, and i pushed around 17 to 17.5. and it sounds like you drive like me, so i have no idea. but it goes south if i'm in town.

 

I'll be the first to admit that only get 20-21 mpg when the truck stays on the interstate/highway and under 2k on the tac and cruise control on. The only think non-stock on my truck is the bed cover...so I'm sure that helps. I don't always get 20-21, but I usually stay above 18.5 as long as I keep the truck out of city traffic and my foot out it! The mileage shouldn't be that much different between the 7.3 and 6.0, they aren't that different and at highway speed the 7.3 wouldn't have to work as hard as the 6.0 to maintain speed.

 

800 mile round trip this weekend in flat lands with no winds and empty, averaged 18.67 with cruise set at 75 both ways. 44K on the truck and totally stock.

Front tires set at 65. Rear at 60.

 

Very Good King! I assume that is hand calculated as well. I think this is very representative of what a good performing "stock" 6.0L truck is capable of. I think that you could have bumped this up by 1 mpg or maybe a little more by going 60 (not that that is easy to do ).

Also - please let us know the following:
What Rear end?
Torqshift or manual?
Cruise or not?
What size tires?
Any mods, additives or synthetics?
Using Air Conditioner or not?

 

I posted this on another thread but last weekend on a 375 each way trip trying an experiment to get the very best mileage I could possibly get was 19.1 hand calculated.
Tires inflated to 75PSI
Tonneau cover
Kept between 60 - 65
Used the Cruise control as much as possible.

In normal driving I only get about 13.5...

It's been my observation that almost every vehicle goes into it's highest gear at about 52 - 53 MPH. I think this was done by the manufacturers to try to get the best highway MPG in testing for the gov when the test were run at 55 MPH.
Any speed above that will decrease your mileage as the drag increases as a square to the speed increase.
But who can drive around at 55 MPH???

 

I decided to check my tires.

I have Michelin 285 75 R16 M & S on my truck max PSI cold calls for 65 PSI and that is what I am running them at. So, I am where I need to be as far as tire inflation effecting my MPG.

David

 

If the sticker in the door jamb of your truck calls for 65, that is a start. I know Ford put 75psi on the jamb of my '04. The 4X4 front-end is going to hurt your mileage do to the weight and resistance of the axle....so in all likely hood your not going to get as good as mileage as a 2WD, but then you don't have a pavement princess like I do.

 

Yes, hand calc'd. The meter read 16.4 but hardly moves since I've reset it only once in the entire life of the truck.

3.73 rear
Torqshift
Cruise all the way.
275/65/20 (nearly bald, I may add..)
No mods, adds, or synths.
A/C on entire trip

Did a San Diego trip late last year where I average 19ish (can't remember exact figures) but I was doing 70 and had 3 more passengers plus slightly more cargo. Either way, 70 is just too slow for I-8 and for me as well. Everyone is doing 85+ most of the time.

 

My '06 F-350 CC 4x4 came with 275/65-20 series E tires with a max inflation of 80 PSI but reccomended to run at 75/70 so I figured that running at 75 PSI would not hurt anything.

 

well I'm convinced this truck is junk, did the exhaust and it didn't matter. Still right at 16.9 mpg and that is with cruis at 67mph, empty, tailgate down, not crap for cargo. Buddies in the duramax and cummings get about 2mpg better than that with the exact same truck and when they hook to a trailer with 100ft lbs of tq extra you can tell. Think I'm visiting the chevy dealership tomorrow. Just done messing with this POS.

 

I am getting just shy of 18 MPG with mine. I run tire pressure at 75, just changed to synthetic oil, am running Matt's General Economy tune and the mods in my sig. I will be putting the front half of the MBRP 4" exhaust on once I'm out of warranty in 12K miles. I've been thinking about a water/methanol system but will probably go for a regulated return first even though it won't help mileage. I run cruise on the highway and keep it under 70. I'm hoping to see a bump once we get "winter fuel" out of the supply chain.

 

Did the 4" exhaust Thursday. Installed the AIS yesterday and recently did the Zoodad. So, I'll be tracking the MPG and see what difference it makes. Mine is a 4wd and I do carry about 1K in the back all the time. I'm not looking to get the mileage of a Honda Civic but if I could get 18-19 I'd be happy. We shall see.

David

 

SC_DAve - looks like you may be posting in the wrong Forum. This is 6.0L and your sig says 7.3.