MPG Reality Check

[Chuck Wheeler]

Several things could be affecting Bob’s
mileage.

1. He is towing.

2. I don’t know where he is in WA,
but there is a lot of it that is more like mountain running.  I can run 800
miles and not change over 600ft elevation.

3. Do they pump a “winter blend”
of diesel in WA?  My mileage in the truck has always been lower on “Winter
Blend”

3. He has more power than I do and when
the power is there we tend to use it. My cousin followed us on a trip with his Monaco and he
gained almost 2mpg driving the way we have to.  (He said it wasn’t worth
it!)

4. We do a lot of winter traveling and so
it is not necessary to run the generator.

5. I believe that a “California” engine
runs with different injection timing and advance curve.

6. I usually run with Gray and black water
tanks empty, about ¼ tanks of fresh water and on the bottom half of the fuel
capacity to keep my weight down.  That’s why I have to compute mpg over a
many miles to get an idea of what milage I am getting.

I track milage mainly to keep an idea of
how the bus is running. 

- Chuck
Wheeler-

1982 FC 31SB Fort Worth TX

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From: WanderlodgeForum@yahoogroups.com [mailto:WanderlodgeForum@yahoogroups.com] On Behalf Of ebirder2000@...

Sent: Monday, February 15, 2010
2:39 PM

To: WanderlodgeForum@yahoogroups.com

Subject: Re: [WanderlodgeForum]
MPG Reality Check

Bob, I don't dispute your method or your
finding at all. My only comment is, that mileage seems too
low.I would expect thatyour mileage would be closer to 8mg.
But,that's only based on other folks bragging including my own,that
I have observed.

Steve (at Painted Rocks campground). Temp
80 degrees with absolute clear blue skies.

In a message dated 2/12/2010 12:22:01
P.M. Pacific Standard Time, sundance101@comcast.net writes:

Finally, after 7 years,
I filled the fuel tank to the top, drove 1015 miles, and filled it again. The
167 gallons calculates to about 6 MPG.



The method has plenty of potential for error. The odometer reads low and I
don't have a GPS. I used the Google mileage plus 5% to account for wrong turns,
finding RV sites, etc. The route was Brookings, OR to Q by way of Hwy 101 and Malibu, CA.



The tank is so big that I figure the fill could be off by as much as 10%. If
the fill-up were 10% low, the MPG would have been 6.7. If the fill-up were 10%
high, the MPG would have been about 5.5.



Other details: 1984 FC31 with California
210HP turbo 3208. Road speed about 58 MPH. 4.89 gears. 11R22.5 Michelins at 105
and 95 PSI. Towing a Honda CRV. Air filter has about 5000 miles. The air intake
is the enlarged version designed for the 250HP turbo engine. Never blows any
black unless I make an operator error.



To achieve the 10 MPG sometimes suggested for the FC, my mileage estimate would
need to be off by almost 700 miles, or the fill-up would need to be off by
almost 70 gallons.



I'd be interested any anyone else's MPG observations and the method used.



Bob Griesel '84 FC31 WLII WA