Anyone tried the old skool method? Install a vacuum gauge and see just where the sweet spot is on YOUR motor? All motors are just a little different. Every car I have ever owned has gotten a vacuum gauge installed. Oly

edit If you run a 4100 carb you can use the vac gauge to set where the secondary's dump. Note the vacuum at which the secondaries open. Compress or stretch the spring to change when it dumps.

 

 

• 2018 Lariat SuperCrew 'Sport' 4X4
• 5.0 V8.
• 3.55 rear gear ratio.
• 9,800 miles on odometer.
• Transmission Mode set to: Normal
• Michigan winter gas blend (probably yields worse mpg than summer blend in summer conditions?)
• No appreciable 'wind' in any direction....

Gassed up at fuel station right next to 'on-ramp' of highway. Entered highway under light/moderate acceleration. Put F150 on 'cruise'... speed set to 70 mph. Drove 60 miles down highway. Pulled off highway and right into another gas station. Filled up tank.

Computer MPG read: 20.9 mpg
Hand Calculation was: 20.03 mpg

Fairly close... computer was within 1 mpg difference.

Not sure the EPA sticker of 22 mpg highway is attainable in real world driving. Maybe with Summer Gas blend???

Under everyday driving conditions with 75% rural 55 mph roads... some highway and some city... I generally average low 17 mpg on computer.

 

Well done Joe. Try 65 or so next time.

 

Thank you D-D-in-KY. I will try that once and see what the difference in mph yields. I bet the results will be very interesting.

 

Wow! I’ve learned a lot from this thread. Thanks to all.

 

Followed a Corvette across South Dakota on I 90 at 87 mph. Dropped my 2018 5.0 to 19. Costs a little more but you sure do cover some ground. Speed limit on I90 is 80 mph.

 

Is a gotts mod really worth doing, since these pickups have a factory CAI.

 

I did some experimenting while towing my TT home from Kentucky yesterday. I found that using the Adaptive Cruise set to one bar, in Tow mode, if you set it to 70, which was the speed limit, and get behind a semi going 65 or so, the ACC will keep the truck far enough back to be out of the shake zone, far enough back to not be tailgating, yet still be in the draft effects from the semi. I saw a 3 MPG increase over doing 65 with no truck in front. It went from 9 MPG to 12 MPG. Doing a steady 70 MPH nets roughly 8.8 MPG, 65 nets 9.5 MPG, 55 nets 13 MPG, and shadowing a semi @65 nets 11 MPG.

I was bored driving home, can you tell. I haven't filled up since I got home last night, so don't have the completed Fuelly totals yet, but my total average is setting at 10.3 MPG for now. I separated my towing MPG from the overall MPG using the missed fill up portion of the app, so this way I can keep track of towing verse daily driving, and get a good overall view of lifetimes since towing drastically affects the lifetime averages if you do more daily than towing over the lifetime. It can show the lifetime being at least 4 MPG less than it actually is. If I were to take out entries 4 & 5 from my DD, which was the first towing trip, and mark it as a missed fill, then the average would be exactly where my dash is, which is nearly 22 MPG, but shows as 20.7 instead.

If I want to know the overall DD + towing, Trip #2 has never been reset since I drove it off the lot, and my dash reading is accurate to within .2 MPG.

 

2018 XLT SPORT 3.5 turbo stock

MPG per monitor - 22.3 mpg
Hand calculated - 21.2 mpg

This is 80% hwy 20% city, very conservative driving.
Included about 2 miles of heavy traffic where it took 45 minutes to move 2 miles.

I am very confident that this truck will do 25 mpg on straight hwy 60 - 65 mph, on conservative driving. 50 - 60 mph is the sweet spot for best mpg on most modern cars and trucks.