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-   -   UPDATE : My True MPG 7.3L V-8 Gas (https://www.irv2.com/forums/f87/update-my-true-mpg-7-3l-v-8-gas-532975.html)

Unclepaul 04-28-2021 08:55 PM

Drivers tend to get better mileage when they are doing measurements. Want to be able to claim a high number.

Dval 04-29-2021 10:18 AM

Quote:

Originally Posted by Unclepaul (Post 5730906)
Drivers tend to get better mileage when they are doing measurements. Want to be able to claim a high number.

I don't seem to get what other people report for mpg ? If I can over 9mpg with mine I will be happy .

R.Wold 04-29-2021 10:39 AM

Quote:

Originally Posted by wayfarer2021 (Post 5715965)
The only real way to know your true MPG is to manually calculate it. Once you do this you will know how accurate the Ford displayed numbers are. Your 1000 mile trip will be a great time to do this. I use an app on my phone to track MPG and other expenses.

What app do you use?

Quote:

Originally Posted by jackreno (Post 5730294)
Well just got back from a long trip well over 1000 miles and my average gas mpg reading on the Ford dash display reads 11.9 mpg.

Did check from fill up to fill up and read the miles driven and on that one leg of the trip it showed 11.3 mpg while the Ford display reading was 11.5 mpg on that leg of the trip, so it appears the display on dash is very close to actual miles.
[ no generator use at all on trip, no need for a A/C ]

I am very pleased with the mpg on the Ford 7.3L gas V-8, at 64 mph flat road no wind it reads 12-14 mpg, lots of extra power even in the mountains in Idaho and stayed in 6th gear almost all the time, never had to push the gas pedal beyond half.

Ford got this motor and transmission combo perfect, best I have even owned.

Does it have a +/- rocker switch on the shifter to lock out higher gears? I have it on my ‘17 F-250 - I believe they call it “select shift”. It’s designed for use while shifting in “M” (manual) mode, but also works for locking out higher gears in D. Very handy for eliminating all the hunting between overdrive and lower gears while climbing grades etc.

Quote:

Originally Posted by jackreno (Post 5730441)
Best I have ever owned..

Why does edit go away after a hour or so ??

Company policy....

Quote:

Originally Posted by Unclepaul (Post 5730906)
Drivers tend to get better mileage when they are doing measurements. Want to be able to claim a high number.

I think this is true for me - when checking MPG I tend to keep my foot out of it a bit and drive more conservatively.

jackreno 04-29-2021 03:05 PM

Quote:

Originally Posted by R.Wold (Post 5731425)
What app do you use?



Does it have a +/- rocker switch on the shifter to lock out higher gears? I have it on my ‘17 F-250 - I believe they call it “select shift”. It’s designed for use while shifting in “M” (manual) mode, but also works for locking out higher gears in D. Very handy for eliminating all the hunting between overdrive and lower gears while climbing grades etc.



I think this is true for me - when checking MPG I tend to keep my foot out of it a bit and drive more conservatively.


My 2021 Ford E-350 does not hunt at all in the mountains, unlike my 08 F-53 did, it stays in 5th gear and sits there, not bragging its just a fact, maybe its my weight I don't know but its the best RV I have ever owned and I have had 3 other motorhomes in the past.
[ 11,500 lbs fully loaded with 2 passengers ]


And no I did not keep my foot out of my RV on this trip, drove it like I will always drive it, 62-65 mph highway is my normal, cruise control on all the time.

jackreno 04-29-2021 03:22 PM

Quote:

Originally Posted by Unclepaul (Post 5730906)
Drivers tend to get better mileage when they are doing measurements. Want to be able to claim a high number.

Not with me, I drove my RV on this 1000 mile trip like I always drive, 62-65 mph cruise control on.

My average was at or above 11.5 mpg, not bragging just a fact.

The reason I am posting this is if someone is thinking of a new 7.3L V-8 small class C under 26 foot and under 12,000 lbs loaded you will be surprised by its mpg over the older V-10's.

Before I bought my BT Cruiser 5240 was asking on here the mpg on class C's and many posted 8-10 mpg and so I thought that was what I was going to get and bought the V-8 E-350 over the V-6 Transit class C's, but by my surprised I am getting close to what the V-6 Transits class C's are getting without screaming rpm's in the mountains or dealing with the turbos when they have issues..

Ford hit it out of the park with the 7.3 V-8 and 6 speed Torque Shift transmission on the E-350/450 super duty chassis.

Never goes above 3900 rpm's and sits in 6th gear 90 percent of the time.
[ at 62 mph 6th gear its 2100 rpms on the motor ]

If anyone is thinking buying used V-10 vs new V-8 I will say buy new..

:D

gsuders86 04-30-2021 09:30 AM

Thanks for posting this info. Wife and I were looking at RV and I wasn't sure how good the new V8's would be vs the tried and true V10s.

arcaguy 04-30-2021 09:47 AM

Quote:

Originally Posted by jackreno (Post 5730441)
Best I have ever owned..

Why does edit go away after a hour or so ??

Because that's the way the software is written or set up. I doubt it's going to change but I guess if enough folks complained it might be able to be changed. I've just taken to proofreading what I've written.

Phil G. 04-30-2021 11:19 AM

FWIW, we have a small Class C built on a Ford E450 V10 chassis with the 5-speed 5R110 tranny (5 gears under manual control, with one of the gears being adjustable between two ratios under computer control).

I drive it conservatively - rarely above 3900 RPM on grades if at all possible, using Tow/Haul mode whenever appropriate, and cruising at only 58-60 MPH (2100-2200 RPM) for a very quiet engine.

I think we may be squeeking out around 10 MPG, on average. I don't keep fanatic track of gas mileage because I've discovered that's the least of our expenses in owning a motorhome. :cool:

RonandDeb 04-30-2021 07:47 PM

That's a pretty good avg. Right or wrong, it's much easier to look at the dash and see what the mpg's are. Precise calculated spreadsheets don't impress me as it's not worth the work. If you're low on fuel, you're going to fill up anyway so true mpg's don't really matter unless your budget is that tight.

My MB diesel is averaging about 13mpg, from what the dash says anyway..

jackreno 05-01-2021 12:19 AM

Quote:

Originally Posted by RonandDeb (Post 5733384)
That's a pretty good avg. Right or wrong, it's much easier to look at the dash and see what the mpg's are. Precise calculated spreadsheets don't impress me as it's not worth the work. If you're low on fuel, you're going to fill up anyway so true mpg's don't really matter unless your budget is that tight.

My MB diesel is averaging about 13mpg, from what the dash says anyway..

I tested the dash mpg to actual fill up from one gas station to another gas station on one part of my trip and the dash average read 11.5 and the fill up test to mileage was a tad over 11.3 mpg.

I would say the dash reading is very close to accurate so I use this as my gauge .

When I got back to Vegas my dash reading was 11.9 mpg average so I go with 11.5 as my true average.

[ yes I reset the average mpg reading when I left Vegas at my driveway and never touched it during the trip back to Vegas ]


My budget is not tight but it sure is nice to drive a motorhome around and get this kind of gas mileage compared to my other 3 motorhomes that I owned that never saw above 8 mpg on its best day..

1979 Xplorer class C 23 foot long, 440 Dodge motor 3 speed trans.
2002 Flair class A 27 foot long, 8.1 GM motor 4 speed trans.
2008 Bounder class A 33 foot long, Ford V-10 5 speed trans.

All 3 above were good motorhomes with good motors but I will say it here the Ford 7.3L V-8 with the 6 speed trans is by far the best of them all.

Ford truly got it right with this motor/trans combo... :bow:

nodine 05-01-2021 06:01 AM

Quote:

Originally Posted by AJMike (Post 5730495)
Well, yes and no, at least IMHO.

Filling up at different stations means using different fuel pumps, and the automatic cutoff on different pumps work differently. Some pumps cut off too early, giving you the impression that you have gotten high mpg figures than are accurate, and then the next fill up is likely to show a lower figure. And neither of those figures are likely to be accurate. I believe that is even true when you don't accept the automatic cutoff as being the final word and add more fuel.

It has been my experience that computing the figure using the miles and gallons works properly only when a lot of miles and a lot of fill up are involved, and that is why I only use those figures at the end of a relatively long trip - say 2000 miles - or after a lot of fill ups, perhaps 10. Then I assume the multiple figures will average out to something fairly accurate.

FWIW I have found the mileage figure the Ford Transit 350 HD chassis gives me in my Winnebago Fuse is pretty accurate, usually no more than 0.5 - 1.0 mpg off at the most and I have come to believe it.

Also don't forget the change in temperature of the fuel from fill up to fill. We have a diesel with a 100 gallon fuel tank and always stop at the Sam's Club 12 miles from home and fill up. We then drive home and put the coach in a heated garage. I filled it up in February when the temps were cold. A few days ago I decided to empty a gallon of clean diesel I carried for on the road filter changes into that 100 gallon tank. When I screwed the camp off the fill tube diesel stared running out. The fuel in the tank had expanded that much from the fill up in February.

Bob

Ron Dittmer 05-01-2021 06:32 AM

Stating the fuel economy of a motorhome is not an easy "declared number" answer. There are so many variables that must be considered. Here are the MPG stats on our rig and how the numbers are calculated.

I write down the odometer at the first fuel fill-up at home, then a second time once back home when the trip is completed. My log is only how much gas is purchased to the 100th of a gallon. That first fill-up is logged in as "0" gallons purchased to start the trip.

- Our trips originate in the Chicago area.
- We head westerly which always involves driving across the Great Plains.
- Our trips vary between 5000 and 6000 miles.
- Our practiced cruising speed is 67-68 mph.

- 2007 E350 chassis
- 6.8L-V10 with 55 gallon fuel tank
- The motorhome is very aero-dynamic as shown below.
- Rig dimensions: 9'-10" to top of a/c unit, 93" wide, 23'-8" long
- Actual trip weight with us inside averages around 11,250 pounds.

We average 9.2mpg when towing the 4200 pound Jeep Liberty shown here.
https://live.staticflickr.com/4038/5...1fdc6468_z.jpg

We average 9.5mpg when towing the 2200 pound Toyota MR2 Spyder shown here.
https://live.staticflickr.com/7023/6...1be1621e_z.jpg

We average 10.5mpg when we don't tow another vehicle.
This was only one trip where our cruising speed was lowered to 62mph, an experiment to achieve "best possible" fuel economy.
https://live.staticflickr.com/3495/3...4c364696_z.jpg

Here is the frontal profile of our rig aerodynamics.
https://live.staticflickr.com/2432/3...411a139a_z.jpg


CLICK HERE to see many pictures of our rig.

jackreno 05-01-2021 09:35 AM

Quote:

Originally Posted by Ron Dittmer (Post 5733635)

We average 10.5mpg when we don't tow another vehicle.
This was only one trip where our cruising speed was lowered to 62mph, an experiment to achieve "best possible" fuel economy.


So it appears the new 7.3 V-8 does get better fuel mileage as Ford stated it would over the V-10.

My RV is about the same as yours in weight, height and aero dynamics.

Ron Dittmer 05-01-2021 05:02 PM

Quote:

Originally Posted by jackreno (Post 5733872)
So it appears the new 7.3 V-8 does get better fuel mileage as Ford stated it would over the V-10.

My RV is about the same as yours in weight, height and aero dynamics.

I heard the new Ford V8 Godzilla engine teamed up with the latest transmission offers improved fuel economy. I am glad to read that you are experiencing that.

Years ago the E350 that we have was built with different gearing in the differential, compared to the E450. It does not pull as strong as an E450 but given the lighter load, it doesn't need to. That difference offered better gas mileage, roughly one more mile per gallon. Later, Ford added more gears in the transmission which rendered the gearing in the differential a mute feature, so for a number of years now, the E350 and E450 have the same gearing in the differential.


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