daleboot

Been browsing the forums a bit and found the massive threads and stickies on mpg, they all seem all over the place regarding model, year, engine, etc. So I am hoping I can get a bit of direct feedback on my situation.

Just bought a 2013 Supercrew platinum 4wd 3.5 ecoboost with the shortbed and 3.73 gears with 65,000 miles on it Awesome truck, just quite disappointed in my mpg.

We went on a road trip with the wife and 2 younger kids and a bunch of camping gear in the bed. which was covered with a canvas bed cover. I was doing 70-80 most of the time and was never really heavy with my right foot. We got any where from 14.5-15.5 mpg doing almost totally highway driving. I figured well it was windy and we had a lot of gear, been back for a week now and my wife is driving it to work and back. She is getting around 15mpg and she takes it pretty easy and is about part city and part hwy on her drive.

Before buying the truck and checking posts,talking to friends etc I expected at least a few mpg better than. I already adjusted my mileage for the tire size that is a bit bigger.

The tires are BFG AT2's in an LT so I know that hurts things a bit with the weight, but wouldn't think it would be a ton. Id does also have a small lift(maybe 2")

Is this really what I should expect with the setup I have or is there something way far off that I should start looking into.

THX

McLovin

Joe F

You also might want to check mpg the old fashioned way. Fill up, drive it, and then see how much it takes to fill it up again compared to how many miles you drove. mi/gal = average mpg. I have a 2013 EB 4WD, leveled, stock wheels/tires, 3.73 rear end, and a 36 gal tank. My dash display short changes me by about 1mpg or so. Over a tank of gas I average around 17.2 with mixed highway/city driving. Recently I moved my daughter across the state for a summer internship and doing those 150 miles loaded up in the back with all of her stuff including a bed and dresser, I averaged 18.3 on the highway (averaging 70-75mph). 18.5 while empty on the way home.

Edit: I am at 59K now and did the plugs/boots plus cleaned all three MAP sensors at about 55K. mpg improvement since has been negligible.

schmenke

With everything you've described (3.73 gear ratio, full load, heavier wheels/tires, lift kit, wind, 80mph...) that doesn't sound unrealistic at all.

bassJAM

With a lift and oversized tires yes, that's about what you should expect. The lower rear gear probably doesn't help much, but the lift and tires are doing the most damage.

That being said, after I drove my ecoboost for a 3-4 months I saw my mileage improve a couple mpg's. You can't drive it like a naturally aspirated vehicle, I can't really explain it but once I learned how the engine behaved and adjusted my driving style I started doing a little better. Also, stay below 75 mph on the highway. If I cruise at 72 I can do around 19-20 mpg (strictly straight level highway on 2 hour road trips) but I drop to 16 once I get close to 80. My hand calculated average for the past 18 months has been 17 mpg with about a 30/70 city/highway mix. I do a little better in the summer, and a little worse in the winter since I let my truck warm up for 5-10 minutes every morning once the lows drop below 40°F.

daleboot

Ok... 60K seems early to be looking at plugs, but Ill pull a few to make sure. I guess being a turbo engine it could be a bit different,but seems like most all newer cars/trucks are easliy going 100k plus on plugs.

Checked mileage by hand and would have more exact numbers, but hadn't at the time figured how much my speedo was off with the bigger tires. So I wasn't going just off the computer.

Does the lift affect areodynamics that much, I guess if it levels it a bit rather than having the front lower that affects things. Do the actually diameter of the tire cost your mileage much as well or is it mostly that it changes your speedo/odometer and the math needs to be adjusted?

We were probably doing closer to 70-75 most of the time and since we got back my wife is babying the truck and still getting about the same. Seeing more and more posts claiming much better mileage even with 3.73's and a a full load.

schmenke- The truck did come from your neck of the woods and we are outside of salt lake city, so I am guessing climate/elevation are not much different.

Anything usually done different on Canadain trucks with the computer programming or fuel used up there. Maybe just need a few more tanks for things to adjust better. , THX

frosty19

My '13 FX4 with the ecoboost, stock size tires and ride height with regular weekly driving gets around 13.5L/100km (17mpg) at roughly 60% highway/40% city driving right now. Its probably time for plugs and an air filter soon (145k km, 90k miles) and then I will see what i can get on a highway trip.
This is my second turbo vehicle and wind is a big MPG killer with them I find as they are in and out of boost sporadically to hold a constant speed

Eduskator

1) Did you hand calculate or rely on the lye-o-meter?

2) 3.73 gears + lift + LT tires = MPG killer. 14-15MPG is in fact normal for your setup.

3) As other said, you might want to change the plugs.

4) Also, proper tire inflation is a must when it comes to saving fuel. Make sure they're inflated as per your specs.

5) 70-80 mph is fast. The faster the speed, the less aerodynamic it is. Try going 60 instead, I'm pretty sure you'll see a nice increase in your MPG.

schmenke

Yep. Let's remember that drag force is proportional to the square of velocity, so your fuel economy will increase exponentially as you increase speed.

bassJAM

Yes, and yes.

I spent a lot of time searching all the threads out there specifically on the fuel mileage hit when I was contemplating a leveling kit and oversize tires. Seems a 1-2 mpg hit from a lift is common, and a 1-2 mpg hit from larger tires is common. I drive 20k miles a year, so a 2-4 mpg loss was enough to stop me from changing my trucks stance.

The lift hurts your aerodynamics and forces your truck to work harder to push air out of the way. You're letting more air under the truck which creates more drag on all the nooks and crannies down there. There's a reason modern trucks have those huge air damns that lower your ground clearance.

The larger tires hurt in three ways ways; 1) they are heavier and make your engine work harder to turn them. 2) they have a larger diameter and make your engine work harder to turn them. 3) they often have all terrain or mud terrain tread patterns with higher rolling resistance, which yep, makes your engine work harder to turn them.