Well, I refilled today in my 1999 U320. VMS predicted I used 140 gal. When I filled up it was 152 gal. No generator used. So this means I need to multiply VMS' estimate by 152/140 = 1.085, or just add 10% to VMS' prediction to be conservative.
194-152 = 42 gal or 22% of a full tank. I doubt I'll play it this close again. Driving in the top half of the tank is a good feeling.
1133 miles / 152 = 7.45 mpg. VMS had it as 8.1 mpg 8.1/7.45 = 1.087, effectively the same as the fuel difference alone.
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best, paul
"Thriving not surviving" <(*¿*)>
Paul Schaye (at 2008 NYC Marathon)
See our blog at LazyDazers.com
Hmmmm....I wonder how much of that difference is "pump 'error' "? I could swear that these pumps are "programmed" to yield less than the "pump reading" displays.
These "smart" pumps can be set to deliver the first 5 gallons very accuratelly, but after that who knows what they deliver. In this way the Weights & Measures operatives can take their test measuring can and test each pump, but 5 gallons? Who fills with 5 gallons?
Well, I got the fuel from Pump 13 at the Flying J in Richfield, UT
(Exit 40 on I-70).
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best, paul
"Thriving not surviving" <(*¿*)>
Paul Schaye (at 2008 NYC Marathon)
See our blog at LazyDazers.com
Paul,
Before you make that 1.085 a hard and fast correction factor, consider adding a half dozen fill-ups together and then calculating a correction factor. You might be surprised how much difference a very slight off level condition can make in how much fuel will flow into your tank. Mine varies enough that I gave up trying to get consistent factor.
I agree, " Driving in the top half of the tank is a good feeling."
Paul
36' 2000 U320
Good idea!
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best, paul
"Thriving not surviving" <(*¿*)>
Paul Schaye (at 2008 NYC Marathon)
See our blog at LazyDazers.com
Have you calibrated the VMS speed with a GPS?
No, I have not calibrated VMS speed. Perhaps I'll try to find the GPS and see (we pretty much rely on iPhone for directions these days - street directions, that is ;o) (Which reminds me. Kathleen and I have agreed we both need close supervision. So if I make a wrong turn and Kathleen did not try to stop me from doing so - it's HER fault, not MINE ;o) By the way, we celebrated our 51st yesterday:
http://lazydazers.com/index.cfm?fa=ShowItem&ID=3031
I do notice a difference between dash speedometer and VMS. For example, 6th gear kicks in at 61mph according to dash speedo, and at 62mph according to VMS. 62/61 = 1.016 (if I had the actual speeds the speedo and VMS thot was happening to more significant digits, 1.016 might turn out more like the 1.005 below)
Total miles according to dash odometer are less than miles according to VMS, by a factor of 1.005
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best, paul
"Thriving not surviving" <(*¿*)>
Paul Schaye (at 2008 NYC Marathon)
See our blog at LazyDazers.com
Dave,
I have and the VMSpc, coach speedo and GPS speed are all virtually identical in/on our coach.
Paul
36' 2000 U320
My first thought is how would I have to drive my 36' 01 320 with 1 slide to get that poor mileage.
Having driven it about 25K miles, flat land and mountains (eastern), If I got that kind of mileage I would be going over a few items, like air filter, tire pressure, toe in and dragging brakes trying to find a reason for the poor mileage.
Would be worried about the change/drop in mileage from my normal 8.6-8.9 mpg for trip.
I find the ISM 450 in the 01 36' is close to a hot rod compared with other units on road, most pass me on level or down hill, but I run past them all on the mountain grades/up hill.
Also my VMSpc and two GPS units agrees with speedo exactly.
Last trip VMSpc said I used 105 gal, took 107 to refill, did run the genset for a few hours.
Dave
Hmmmm..... I guess you're referring to me.
First off, my U320 is a 40 footer, not 36. Only about 500 lbs under CCC. Towing a Honda Element.
Now the route for the 1133 miles / 152 = 7.45 mpg
Tye, TX / Lubbock, TX / Clovis, NM / Santa Rosa, NM / Tijeras, NM / Santa Fe, NM / Pagosa Springs, CO / Durango, CO / Grand Junction, CO / Richfield, UT
Western mountains and some nasty cross and head winds might have had something to do with the 7.45 mpg. As the roads turned the effect of wind on VMS mpg was very noticeable.
I'd be interested in the mpg experience of others in Western mountains.
For example, just today climbing mountains in Utah/Nevada my VMS was reporting 4 mpg avg and I was not pushing hard. On level ground I was seeing 9-10 mpg with no wind to speak of.
___
best, paul
"Thriving not surviving" <(*¿*)>
Paul Schaye (at 2008 NYC Marathon)
See our blog at LazyDazers.com
Paul, I get your point, and am wondering the weight of the 99 40' no slide vs the 01 36' w/slide.
Last trip I was not towing.
The fuel mileage is a joke, who cares, if it gets 5 or 15 mpg, would it change how much you used it.
If I were concerned about the mileage, I would have a MB Sprinter under something, Yikes!!!
:))
Dave
The silverleaf and the gallons I need are pretty close if I level before filling and fill to the same point. I tried that on a trip to MN and back to VA this July. I know that I will out in at least what it says I used every time. I also have figured out that I will have to add seven or eight gallons for the genset if it is on the whole time. For example, I had it on in Alabama when I foiled up and never turned it off. When I filled up in Shreveport I needed 7more gallons but it had cooled off and I was only running two AC units I need two more gallons for the third unit but it is much easier on them and the coach is cooler when it is over 102 degrees out.
I get 7.4 plus or minus a bit depending on traffic or mountains but over 3500 miles with out trying for increased fuel mileage I got 7.4 if I try for it I can make close to 8. I tried on the flat land of Al to Shreveport and I got 7.6 but there was an accident that had us sitting for thirty mins. Kills the fuel milage rolling slowly like that.
More recent data on MPG:
http://lazydazers.com/index.cfm?fa=ShowItem&ID=3036 (http://lazydazers.com/index.cfm?fa=ShowItem&ID=3036)
best, paul
Paul,
I just completed a trip from my home base in Fredericksburg, TX to Glacier NP via the Grand Tetons, Yellowstone, Mount Rushmore and Buena Vista, CO (4500 miles). I averaged 8.06 per VMSpc and that matches very close to my own log. I find that identifying the actual fuel level in the tank is a lot harder than I thought, but with the size of the tank I know 5 or 10 gallons would not be hard to miss visually. I have the fuel tank set at 190 gallons on my VMSpc just to have a little fudge factor and I'm thinking of lowering that amount to 185. During my trip I was around 750 lbs below CCC and towed my CRV. I usually drive 63 MPH until I hit the mountains. This was my first trip to the mountains in the FT and I must say it was a pleasure. My 1998 Minnie Winnie did not like the mountains at all. The V10 would be working as fast as it could and still drop down to 10 mph on a few passes. That was not really an issue, but going down the other side could be. The retarder is just one of the best features and I would not have another MH without one.
Looks like your MPG is in line with mine at least.
Brad
2000 U320 4000
2008 Honda CRV
I have my VMSpc set at 75% of the tank which is as low as I want to go because the Aquahot & Generator feeder tubes stop at about 25%. With that I know I have a fudge factor if I wont be using the Gen. and to go a little further.
I like to lean the coach to the passenger side when filling so I can see the fuel line better inside which gives me an extra 10-12 gallons.
Then I know I am always filling to the same spot and it is the only way I can read 100% fuel on my digital readout.
Barry! When you lean your coach to the curb (passenger) side to fuel, I hope you are filling from the street (drivers) side. I can easily visualize the process, trying to peek into the tank to see the fuel level. I have adopted the procedure of filling with coach level (I frequently fill from both sides) and stopping at the first click on the nozzle. I know the penetration of the nozzle may not be consistent but this is as close as I know how to assume equal topping off as I can get, for calculating consumption.
Yes , always from the drivers side.
I could not get accurate readings that way as it never stops at the same place on the 1st click.
If I can't get some sense of accuracy in my numbers its hard to get reliable mpg for my purposes.