A little history First, I had the almighty 7.3 for over 300,000. And with the help of the FTE world, I had a BTS trans, a Garret 38r turbo, split shot injectors, I had DP tunes, the Kwick 6637 airfilter and a 4" exhaust turbo back, modified High Pressure Oil Pump ( done before the injectors) . All in the quest of better Mileage. What I got was a Bad azz 1999 F 250 that served me well for 19 years, and the only gain I ever saw was a .5 mpg better after intake and exhaust.

I now own a 2011 F350 4x4 CC SB sitting with a 4" lift, 325x80x20 BFG AT stock. City appears to be around 14 and highway 15.7 ( based on Lie O Meter).. What kind of trouble can I get into here??

 

First off, welcome to the 6.7 section. I hope your truck serves you well.

Secondly, I don't take my truck's MPG calculations literally. They are usually lower than my hand calculated ones. If I were you, I would do some hand calculated mpg's and see where you are at compared with the truck ones.

You're lifted running 40 inch tires. What gears are you running? How much mileage are you looking for? I'm not trying to be a wise guy here but if you're looking to increase mileage on your truck, the simplest way would be going back to stock suspension and stock size tires. That would probably gain you some more miles to the gallon. Just saying. What exactly is it that you are trying to achieve here?

Just remember one thing... Being cool ain't cheap.

 

 

Love the quote, "being cool aint cheap".

So, I guess thats a great question, what am I looking for, honestly, probably an excuse to start moding the truck, as far as cool, to old for that.. now it is just about having fun..

 

I find the opposite to be the case with mine. My buddies too. Usually shows .5 mpg more than hand calculations.

 

I know in the past, if you have a chip, it was best to do hand calculations..although, sometimes you just dont want to know the truth, based on a quick, I believe that at 65mph on my dash, I am doing about 67. I can start laying out the math here shortly and see what I am actually doing.

 

 

Thanks, I got that from a buddy of mine after I bought my 350. While I love the look of a lifted truck and bigger tires, it usually has a negative effect on mileage. If I do anything, I'll level the front. I have plans on getting a snowplow so I don't really want to plow with a lifted truck. You're creating more wind drag by being lifted and those aggressive tires also create more drag as they weigh heavier and don't have a smooth pattern. I get the fun part. I'd love to get an older 6.0 down the line and mod it a little. But my 16 is still under warranty and is the family vehicle. You probably didn't regear after adding the bigger tires because they are 6 inches taller than the stock 275/65R20s. The 6.7 has the torque to pull the truck with the bigger meats on but it still has to affect mileage. I keep track of all fillups but haven't calculated them recently. I'll post up results here at one point. But here in New York with the winter blend, I'm getting 13 to 14 mpg and summertime it goes to 15-16 easily. That's mixed driving. On a road trip to Kentucky, I got 18 mpg and that was doing 70 to 75 mph. It will vary based on wind, flat, uphill and downhill. If you want to have fun, LOWER the truck so she can handle the road better at speed, get a set of tunes with SOTF and blow the doors off the Mustangs and Covettes. Just my 2 cents.

I started keeping track of what my truck says for gallons used and MPG. It usually is at least 1 gallon more and 1 mpg more -- the truck that is than my calculated results.

 

Chuck, you crazy old man you!

 

If you've got the itch already to mod it, and also improve mileage and power...….delete it. No looking back. I'm running 37's with 6" lift, and I get 15mpg in town, just a shade under 19 mpg highway. Towing, I believe about 13, haven't paid attention as much, but it's way better then my modded 7.3 was, with wayyyyyyy more power. Welcome to the 6.7

 

Hey dude, how fast is your highway speed normally and what gears does your rig have?

 

75 mph on highway for most of it, but 65-68 mph on another highway I frequent. I have 3:55 gears, and run max pressure in tires in front always, max on rears only when towing. In town I drive like a grandpa to get the 15. I have tested a few tanks, and if I drive aggressively I have gotten around 13.5. My city is pretty small, so there's no rush haha. Also, I live at 7100 ft elevation, so the lack of oxygen affects power and mileage a bit.

*EDIT* My speedo is adjusted for 35's so it's fairly close on the 37's. All my calculations are hand done, on mileage. I have put it up against the computers numbers, and it's very close...

 

 

Okay but you had 325/80R20 listed. I stand corrected. With the 325/60s, you're just over 35".

 

I know, Bumped out the wrong info,