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Old 06-28-2019, 08:49 AM   #15
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If the mileage was figured to the Imperial gallon in Ontario, you'd have to drop the figure by 25% when talking to Americans ; so 9.5 to the US gallon.

I have had over 9.7 to the US gallon in California where towing speed is 55MPH. but over 8 1/2 years of travel , overall is approx 7.8.

Some reading material , from the major engine suppliers , that basically says , mileage can vary by 20% between drivers.
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Old 06-28-2019, 08:54 AM   #16
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Originally Posted by TonyDi View Post
If you were to search all the threads regarding MPG you would find that almost everyone is getting 6.5-8.5 mpg. I think perhaps the previous owner may have fudged his estimates or he was bad in math.
I wish. I get 5.5 mpg (doesn't matter if I drive at 62 or 70 - seems to be the same).
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Old 06-28-2019, 09:04 AM   #17
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35 foot gassed and we usually get about 7.
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Old 06-28-2019, 09:13 AM   #18
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Accurate MPG is hard to calculate as tank fill sites are not the same, automatic pump shut off is not set as the same across the nation. The best we can do, 'humanly speaking' is guesstamating (new word for ya'll - LOL). I keep a log book for my personal use. I like to know what I'm spending, miles total and between fillups, O/N costs, etc.

I installed the Scan Guage D and really appreciate the information it provides. In this case it gives me instantaneous MPG based on RPM and Boost.

Without Scan Guage D I charted 9.97 mpg from the Flying J West of Knoxville, TN to fill up at Paducah, KY. Consider this was through the mountains climbing up to the Plateau and around Nashville. Drove with Cruise located at 61mph with engine brake on. I was surprised. Driving here in central Illinois using the Scan Guage D I averaged in the high 9s except during a segment of 70mph passing. (Can't seem to keep my foot off the footfeed. LOL).

In defense of the one who sold you the MH I can honsestly say my Scan Guage D said I was cruising at 66mph and averaging 17mpg! WOW!!!!! 'Course I was going down a steep straight grade with a tail wind.

Enjoy your MH. It costs what it cost. My old gassers didn't get any better than what I'm seeing.

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Old 06-28-2019, 09:29 AM   #19
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My MH has a Silverleaf in-dash display and I use it as a consistent reference for fuel economy. I realize it isn't perfect, but using the same device for all comparisons provides for a measure of consistency. Having said this, the Silverleaf almost always shows fuel economy that varies between ~7.8-8.8 mpg depending on conditions and speed.

For example, in Canada with a 100km/hr (60 mph) maximum speed and cruise control engaged we were easily able to achieve an 8.6 mpg on relatively flat terrain. In the US I typically cruise at ~63 mph because it allows my transmission to shift into 6th gear while staying below the 65 mph tow limit for my CR-V. At 63 mph I get roughly 8 mpg. This is with a 425 HP C12 pulling a combined load of ~37,000 lbs.
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Old 06-28-2019, 09:34 AM   #20
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Originally Posted by Farkey View Post
Being new in the RV world I have numerous questions and here is my latest.

At what speed do you people usually cruise on an interstate highway?

I travel at about 60mph because the previous owner said that was the best speed for fuel economy and he would average 12 MPG on a trip.

On my last trip of just under 500 miles, I tried to cruise at 60mph and at the end I got 8.2 MPG. Now mind you that was through the hills in the Finger Lakes, but still getting almost half of what he did.

Unfortunately, I can't ask him any questions because he passed away just after selling me the rig.

So I will be very appreciative of all what you have to say on this subject.

Thank you
Firstly, not everyone is proficient in arithmetic, so 12mpg is more than absurd. Even if, I will only rely on an ECM digital readout, over a period of years, traveling all kinds of terrain.
That said, over the past 12yrs and being the third owner, I'm at 6.2mpg, which I feel is about right for driving a Motel Suite and towing a car behind.
As for speed, I don't believe in driving a behemoth at the same speed as a Vette, so just as long as I can stay in 6th gear OD for the most part, I'm not trying to break the laws of physics. This turns out to be 57mph for me and certainly wouldn't even want to be going that fast, in case of a front tire blowout.
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Old 06-28-2019, 10:37 AM   #21
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"Farkey"......The person who sold you the coach may not have been lying, just telling you what he THOUGHT he was getting. Many will fill their tank and guestimate their mileage. Often, they are waaaaay off. He may have also filled the tank on a slope one day, not completely filling it and did get 12 mpg. Then used that as his average when selling.

I had a similar coach to you, a 2005 Monaco Diplomat. It was a short diesel and not as heavy as some of the newer coaches. I owned that coach for 10 years and tracked every gallon it burned. It ran great and averaged around 8.8mpg. On a perfect day, flat country, no wind, it would occasionally see 9.9mpg. My new heavier coach is getting just 6.8 -7.3 mpg.

If you drive your new to you coach carefully, you should regularly see 8.3 - 8.8mpg. Driving carefully, means no jack rabbit starts (as much as you can do that in a DP), coast to stops and off of off ramps, use the cruise whenever you can and try to let the coach hill climb with the cruise on.
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Old 06-28-2019, 10:45 AM   #22
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Aren't there about half a dozen threads on this topic with all these answers already in it? Consensus was 64-64 mph in most cases.
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Old 06-28-2019, 11:46 AM   #23
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I average 8.5 towing my honda.Since that is two vahicles I must be getting 17 mpg.
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Old 06-28-2019, 02:09 PM   #24
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One factor to keep in mind is which state you purchase gasoline and what time of year. California gas has so many additives for emissions that fuel economy will be much lower. Then when winter arrives the formula is even worse! I have proven this repeatedly in different vehicles. Our Fusion will get 25ish mpg on California freeways. Out of state the same car gets 42 mpg! So you have to factor in what state the fuel is purchased and what time of year.
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Old 06-28-2019, 05:32 PM   #25
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Iím always between 70-80mph.

Regardless of speed i get 6-7 mpg

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Old 06-28-2019, 05:36 PM   #26
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Congrats on the new rig! The 8.2 is probably average for that rig. That's about what we get on our Windsor.

I cruise at 60 MPH and keep in the right lane so as not to obstruct traffic. Have fun and keep her between the ditches!

Good luck, happy trails, and God bless!
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Old 06-28-2019, 05:43 PM   #27
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Originally Posted by bldrbob View Post
I average 8.5 towing my honda. Since that is two vehicles I must be getting 17 mpg.
Since my toad is a hybrid that gets 44 MPG and the coach gets 6 MPG, I get 25 MPG on average.

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Old 06-28-2019, 06:16 PM   #28
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Most all coaches get between 6 and 8.5 miles per gallon of fuel. There are 2 common things that will increase your MPG, alcohol around a campfire and a For Sale sign in the window. Either of these will increase mileage by up to double the previous figure.
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