Driving conditions vs fuel economy
 

Just posting a bit of data here.
Many folks are curious about the base engines in these trucks (3.7, 3.5 in newer body style) and the reason is usually daily driving fuel econ.
I have been tracking my fuel econ on Fuelly for a while now, and use my truck for light towing, and lots of hauling (650+ lbs payload every day)

I average 15.8 l/100km or 14.9 US MPG in my truck. Best tank was 12.3 l/100 or 19.1 US MPG. What I have found is stop and go, and top speeds have the biggest effect on fuel econ.
When i read amazing fuel economy on the forum here of guys in the 3.7 and 3.5 NA, the only time I have come remotely close to claimed economy was on a trip where I did a highway drive at 80-85 km/h due to highway construction, as well as another trip doing 95-100 km/h on the same tank. Both trips very little wind, no towing. (No hills here either)

My assumption is that with the steep gearing of 3.73, the truck prefers the 80-85km/h spot the best. My next assumption is the guys claiming 20 US MPG+ must live where there are freeways and almost no stop and go traffic, with speeds in the 50 mph range.
Even our slow highways where the speed limit is 100 km/h aka 60 MPH my truck does not approach that level of economy, so my guess is the 70 and 75 MPH highways in the US do not lend themselves to guys getting 20+ mpg in trucks with 3.73 gears.

While I have enjoyed the no charge option of the base V6 and since the tuner have been happy with its performance (happier with 87 oct tune vs the 91 since we pay huge hit for 91 here) the real world fuel economy suggests that I might as well get a 3.5 ecoboost or 5.0 on the next truck.

Speed and wind do play a huge part; our trucks have a large frontal area with the associated penalties.

In my 3.73 5.0 (stolen in 2015 :censored:) I got the best mpg at 60mph/100kph.

In my current 3.55 5.0, still get the best at 60mph/100kph but almost as good at 65mph/105kph

You are right, the stop and go is the worst thing you can do for MPG's. You've got a heavy truck that you have to get up to speed and then burn off all that built up energy as heat with your brakes. High speeds are also bad. We are very large and un-aerodynamic and every mph increase hurts us more than say a sedan.

Still though, There has to be something wrong. I see 17-18 driving around locally with a 3.5 Ecoboost, although its not really city driving but steep mountain driving at 55mph. It I were to drive on a totally flat road at 55mph I bet I could see mid 20's. All flat highway at 65mph I have seen 21 mpg. At 75mph I see 17-18 mpg. I too have 3.73 gears and am on 33"(275/60R20) Wrangler Duratracs with a small leveling kit.

The only other thing I can think of is that maybe, since the base V6 lacks the low end torque, it has to spin too fast to get where it needs to go and that wastes fuel. Generally, the lower the RPM's the lower the fuel consumption.

Why not consider a 2.7 Ecoboost. the fuel numbers on those are the best of the entire F150 lineup and they are a small price increase(it was $800 but I think might be $995 now) over the base V6 and offer a huge power advantage. Unless you are racing and need every last HP, the 2.7 has all the power and torque to do whatever any half ton should be doing.

I am thinking I have more weight than I am estimating. My goal is to find a scale soon and weight both axle loads and whole truck. I know lots of 5.0 and first gen EcoBoost guys getting the same or better fuel economy than me. But none of them 20 mpg.
This truck is going out of work service soon. Hopefully next July. Judging by the loads and volume I need to haul around, I'll be in super duty territory. Otherwise a HDPP package ecoboost is needed to get the payload numbers I'll need.
Or maybe if Ford listens to the customer base, they will have a 4x4 or AWD option for the Ford Transit sometime soon.

I use the factory display, resetting on each trip. Wind plays a good bit, stop and go and from what I have seen over the last 5 years, outside air temp plays a factor. Keep in mind, I am driving in the very flat Gulf South between Houston and Louisiana. So other than one bridge in Lake Charles, the majority of the drive is really flat, 70MPH, little stop and go. Obviously ideal for hero fuel economy numbers. In the summers I can get 20.5 to almost 21.5 MPG, if there's no stop and go. Winter time it's maybe right at 20.5, not uncommon for us to see negative density altitudes in winter. The truck is a Super crew 5.0 with 3.55s, 2 wheel drive.

Best I have seen on a trip was 25.5 on a 150 mile trip at 65-67. Wonder what I would have got at 60? Never mind, too hard to drive that slow.

Due to the drag, probably the most efficent speed is around 45 mph, but who can drive that speed on the highway. One thing a lot of people don't know is that wind resistance is based on the square of your speed. So the wind resistance between 30 mph and 60 mph isn't double, but 4 times greater. Between 30 mph and 90 mph, its nine times greater.

I wouldnt be surprise if you were around 5500+ lbs dry weight with a 4x4 scab. The 3.7 is lighter than the EB, but not THAT much lighter. My empty 4x4 screw 6.5' bed is 6140 lbs per the cat scale.

Absolutely. My truck will shift to 6th around 45mph and if I am on a flat road I could probably get high 20's at that speed.

I think Ford listed 5600# for base 4x4 super cab curb weight.
i have the fiberglass topper with light roof rack, and Decked drawers. That's 450#s right there. Easy 100# of tools in back seat (cordless set and batteries and bits, hand tool bags, some electronic meters, corded drill, hole saws etc) and in the box the drawers are full of igniters, capacitors, electrical connectors, circuit boards, a couple electric motors, misc stuff. Another 100# in less frequently used tools, a wet dry vacuum, box of various furnace filters. Copper fittings and pipe.
Also a 6ft ladder on the roof rack almost all the time.
It has to be a combination of the weight, and the fact this city is brutal with untimed traffic lights, no free ways, and a ring road/ perimeter highway where you routinely go from 100km to stopped every few km due to all the at grade controlled intersections.

Haha, with hills, EPA info is very incorrect. :(