I have owned my 2013 ecoboost for a little over two years now. I bought it used obviously, so there are some modifications and I have no idea what gearing it as, if anyone knows how I can figure that out that would be cool. anyway I average between 11-12 mpg. is that reasonable for this motor? I have buddies that average closer to 16 in town and that's why I bought the eco. I do not have a lead foot and drive pretty conservatively. I have been told that I should get a programmer with custom tunes to "adjust" for mods but the mods aren't that huge in my opinion. I know previous owner added cold air intake, bigger tires, dual exhaust, and it appears to have a small lift or leveling kit, will these mods kill my mileage that drastically or should I be looking for a bigger problem somewhere?

 

Larger tires and a lift kit will hurt mileage. Intake and exhaust shouldn't make any difference.

How accurate is your speedometer and odometer right now? Compare it to a GPS and/or highway mile markers.

To roughly check the rear ratio, chock the front wheels, jack up the back, put it in neutral. Mark the driveshaft and rear wheels. Get a helper, turn both rear wheels in the same direction exactly one turn. Watch the driveshaft and count the revolutions.

 

You are the same guy with the 5th wheel question, right? Anyway, all that stuff that was added to your truck will not help mpg's... In fact, as you have seen, it decreases it...

I have a 13 Max Tow with 3.73 gears, oem 20" wheels and get a solid 20 mpg on straight hwy runs going no more than 65 mph.. I get around 16 mpg avg on my daily commute to work and back of about 18 miles each way.

I get 10 mpgs towing my little #5000 TT so it's all about how much boost you need to move your rig with any "mods" it has..

Good luck!

Mitch

 

While not the complete issue, yes, the dual exhaust is costing you gas mileage. The issue is the air speed that the exhaust is moving. As the exhaust moves thru the duel system, it's moving at a far slower speed than a single exhaust. As it's moving slower, it loses heat and gains weight. The engine has to work harder to push the now heavier exhaust out of the system. That causes the gas mileage drop but it is not your entire issue. It'll cause 1-1.5 mpg drop in gas mileage. The better performing exhaust systems are now of a single pipe rather than a duel system to keep the exhaust air speed up and scavenging it faster before it gets the opportunity to become heavier. About the only gains to be had with a stock engine and a custom exhaust is sound. If you like the loud sound, that's about all you'll gain with any after market exhaust system. By comparison to a 1960's engine, we all are driving near extreme hot rods these days as the car makers have pretty much taken any performance enhancements they can use.

 

Besides what has already been noted ... Other issues (to name a few) that affect MPG
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That assumes it has not been regeared. Also, the 2013 Ecoboost does not have a MAF sensor. It uses MAP and IAT.

 

Great info! thank you gDMJOE for the chart, according to that its a 3.73 electric locking rear end. so it seems the fuel economy im experiencing is to be expected with the mods that have been done on that pickup and there isn't anything wrong with it that ive over looked. its a very well maintained truck the cold air intake is a pain in the *** in my opinion (to keep clean and oiled). So the last question I have than is, would some custom tunes help fuel economy, or at the very least help me get the most of my mods?

 

OK ... Contamination of the air intake system.
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I have a 2012 F150 5.0. I got a few 5star tunes with an SCT X4 tuner. The 87 octane tow tune increased my mileage from 15.6 factory to 20.8, plus I got a seat full of performance to enjoy. The 93 octane performance tune returned 18.0 mpg on a recent round trip from Oklahoma City to Houston, driving 80-90.