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Old 07-04-2022, 05:15 AM   #1
Byron B
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Fuel mileage

Happy Independence Day to all!

I noticed in another thread this morning, on towing, that people are mentioning their fuel mileage. My question is: when you say what your fuel mileage is are you stating it from your own calculations or are you using the computer onboard your tow vehicle?
In my last several trucks, presently a Ford and the previous 7 were Chevrolet, I noticed that the onboard computers overstated the mileage by 5-10%.
What say you?
 
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Old 07-04-2022, 05:28 AM   #2
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What I have pumped into the tank has reflected with what the trip logs on the truck indicate, +/- a tenth of a gallon or so per mile. I’ve only done the math while towing on long trips, not when a combination of towing and running unhooked. Not sure if that would make a difference.
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Old 07-04-2022, 07:01 AM   #3
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My current Ford is the only truck and I can speak from because it is the only truck that has had a mileage computer. It was near 2mpg overstated when I first got it. There is a program for Fords only you can download to your laptop called Forscan. You can adjust tire diameter as well as a numerical factor other than tire size to get your MPG calculations near correct. Once I did that, the dash read out near matched hand calculations. People pulling 40 ft trailers claiming 12 to 14 MPG I've always been suspect to me.
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Old 07-04-2022, 07:15 AM   #4
Cat320
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The only accurate way I've found to do it is the old fashioned way of miles traveled divided by fuel used.
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Old 07-04-2022, 08:15 AM   #5
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I get between 8 & 13 depending on wind.
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Old 07-04-2022, 08:16 AM   #6
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Quote:
Originally Posted by Cat320 View Post
The only accurate way I've found to do it is the old fashioned way of miles traveled divided by fuel used.
Us as well. I use the info in the truck computer as a guide, especially for planning fuel stops, but I have found it to be off by about 1/2 mile per gallon in many cases.

I also agree with the observation that wind and terrain make a big difference in the tow mileage on any given day. We recently went to the east coast and the first 2 days on nearly level terrain we had a head / quartering cross wind that was steady at 15+ mph. We got 9.4 & 9.6 on those 2 days. Without the wind we typically get between 10.5 & 11.5
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Old 07-04-2022, 08:32 AM   #7
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I don’t know how someone could get much benefit from knowing someone else’s fuel mileage unless you follow them on a trip. Temperature, terrain, humidity speed all make a difference. Follow me and you will not get 12 MPH. There isn’t much difference in any of these trucks, engine size, turbos, compression ratio, horsepower and torque are all about the same. Don’t expect one to get much better or worse than any of the others.
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Old 07-20-2022, 01:47 PM   #8
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I do not pay attention to the on-board computer mpg and measure it based on miles driven and fuel filled.
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Old 07-20-2022, 02:06 PM   #9
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Driving F450, 65 to 69 MPH, normal KS Winds (20-25mph headwinds no matter which way we are going), I get an average of 8.5 to 9 miles / gallon. Any slower and I get run over on KS Interstates, any faster and I'm out of my comfort zone for pulling any trailer.
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Old 07-20-2022, 05:30 PM   #10
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Based on truck in my signature and miles traveled divided by fuel used I get between 7.23 and 8.19 traveling 60-65 mph
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Old 07-20-2022, 06:03 PM   #11
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8 to 13 depending on the wind. I haven't confirmed as I would assume that the 2020 computer would be accurate.
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Old 07-20-2022, 06:18 PM   #12
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I found it really depends on wind conditions, e.g., head vs. tail and mountain passes. My truck typically gets 12 mph towing my 15,000 lb fifth wheel trailer based on miles and fuel consumed.
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Old 07-20-2022, 07:25 PM   #13
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Originally Posted by mlh View Post
I donít know how someone could get much benefit from knowing someone elseís fuel mileage unless you follow them on a tripÖ.. .
And even then simple driving techniques can make a difference. The person who accelerates harder will get less than the person who is easier on the throttle. The person who looks far ahead, sees a traffic slowing or maybe a traffic light turning, and coast up to the stop will do better than the person who waits til the last second to brake. The person who eases back on the throttle going down hill while still maintaining speed will do better than the person who keeps the rpms up. The person who sees a hill coming up and gains 3-4 mph before the climb will do better than the person who waits until their speed drops before adding throttle to regain speed. All these things and others, basically proactive rather than reactive, can make quite a difference in mpg.

I have gotten in a habit of watching the instantaneous mpg readout, not for absolute numbers, but for trying to keep the gauge toward the higher end. I have found I can do 10-15% better on mpg than not watching it. Now I do it without even thinking about it.
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Old 07-20-2022, 07:48 PM   #14
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scary

I don`t want to know my mileage I might not travel to the far places we want to go if I knew at this point. I stop and fill up (100 gallons with both tanks) when near empty and cough and spit and whine the whole time the diesel pump is running. And I swear I hear someone laughing at me from down in the fuel tank. Last total was $546.00. But I figure a 1000 miles till the next fill-up.
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Old 07-20-2022, 08:30 PM   #15
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Mileage

Quote:
Originally Posted by Foldbak View Post
8 to 13 depending on the wind. I haven't confirmed as I would assume that the 2020 computer would be accurate.
Same here. 9-12 depending on wind speed and direction and I usually tow between 65 and 70.
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Old 07-21-2022, 04:21 AM   #16
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That Ford dash mpg readout/computer is just showing average mpg after each reset. Bearing that in mind, it doesn't take in effect whether you are hooked up or not. Knowing that I just use it as a general guideline since mileage can vary for many different reasons including fuel quality (cetane number or CN) or percentage of bio plus atmospheric conditions. The higher cetane number, the better permanence but as I've found, B10 to 20 wont give better fuel mileage. Then, add in an exhaust filter cleaning process which will instantly knock off 2-3 mpg on that dash gadget.


As far as fuel mileage - if you are towing $50K to mid six figure 5er, you need to suck up the fuel price sticker shock and enjoy (easy to say now that we are RVless this summer) but 100++ buck fill ups are still happening since I still own the TV
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Old 07-21-2022, 05:18 AM   #17
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It's not a true scientific study, but I'm pretty sure I get about 4 mpg (gas) .... (in my John Deere Riding Lawn mower!) ..... With the blade "on"!
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Old 07-21-2022, 05:57 AM   #18
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By my calculations, I get 12.8 MPG towing our 3791RD with our 2014 F350 in the southeast US. When I get up to the mountains in WV (usually as far north as we care to go), I drop to about 9 MPG with 7-9% grades.
Not towing, I get approximately 18 MPG around town, and approximately 21 on the highway.
I only tow at 65 MPH max.
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Old 07-21-2022, 01:00 PM   #19
MandK
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I posted earlier in this thread that I have done the math against my truck’s computer when towing only and not when not towing or in combination so I checked it today in combination. Keep in mind this was only slightly more than a half tank of fuel so more trial would be good. On a full tank and reset the computer, I pulled 242 miles last Sunday and averaged 11.5 mpg on the computer. Then drove around locally to see sights, go to the golf course, out to dinner etc etc. We are pulling out tomorrow morning so I just filled up right outside the park with the computer showing a total of 379.4 miles traveled at an average of 13.2 mpg. I pumped in 28.42 gallons. So 13.35 mpg based on what I actually pumped in. I stopped pumping when the nozzle clicked off and the truck appeared to be level while fueling. Pretty close.
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Old 07-22-2022, 07:58 PM   #20
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no whining allowed

Quote from Dave W "As far as fuel mileage - if you are towing $50K to mid six figure 5er, you need to suck up the fuel price sticker shock and enjoy"

Yeh, you tell`m Dave.................
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