Date: Sat, 1 Jan 2000 19:52:02 -0800
Reply-To: Mark Keller <kelphoto@ISLANDNET.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mark Keller <kelphoto@ISLANDNET.COM>
Subject: Re: Mileage ?
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Marshall,
I run the standard 70 or 75 /205 14" on alloys. The sub-micron filter
continuously cleans the oil, by way of a tee fitting on the oil pressure line.
The clean oil is returned to the crankcase by a fitting I tapped into the
unused fuel pump mounting plate.
I also use a VDO vacuum gage to monitor my driving and the engine. This
greatly overlooked diagnostic tool also allow a careful driver to improve his
fuel economy. The main method is to notice how much vacuum the engine has when
your cruising. The most efficient balance of power and economy for a gas engine
is at 14" of vacuum as I recall. My VDO gauge is even marked with green, good
economy, and orange, poor economy, ranges.
By observing the vacuum at cruise I can adjust my speed so that the engine is
in the "green" The green range starts at 9" and up. There is a green and
orange range from 9" to 5". Below 5" inches the range is orange.
Depending on the wind, I usually consider 65 Mph at 12" vacuum my normal
baseline on level ground. Anything above that I believe a tailwind is
present. With a headwind I try to stay around 10, so if it is a real strong
headwind, I drop my speed to keep the engine load in the green. By the way I
have taken advantage of tailwinds by keep increasing my speed until I am
running at 14" consistently. On one trip of 1000 miles from Ohio to Florida I
had strong tailwinds from Carolinas to Florida. I ran that stretch at 70 + and
still got 23 MPG. The vacuum gauge stay right on the 14" mark most of the
way. Once I was down to 58 MPH in Alberta Canada in a headwind just keep the
vacuum at 8". So it all depends.
The gauge is very sensitive to engine load. At idle, you can observe the
vacuum needle drop to a lower reading by just turning on an electrical load,
like the head light, or wipers.
This is great for situations like yours with a "nose high" condition. Very Very
bad for increased aerodynamic drag, since air is now redirected to the "dirty"
part of your van, both literally and aerodynamic. The undercarriage is full of
flat surfaces which act as air brakes.
I'd consider correcting that first. Because it your engine that is getting the
brunt of punishment by having to work harder to overcome the inefficiency of
the vehicles attitude, i.e. nose high.
A vacuum gauge would confirm this. I used a tee fitting at the fuel pressure
regulator to get my gauge source.
I hope this helps.
Sincerely,
Mark Kelley
91 Carat WLE
Marshall Ruskin wrote:
> Hi Mark:
>
> I also feel that the lower the van sits, the better for fuel economy - I
> want to either lower the front end, or raise up the rear, as the thing looks
> skyward when its sits. Not too aerodynamic as it is, currently.
>
> What size tires do you use, by the way?
>
> I don't know what a sub-micron filter is, is it a low restriction air
> filter?
>
> Anyhow, thanks for the information, and a Happy New Year to you and yours!
>
> Marshall
>
> >Hi Marshall,
> >
> >Since I didn't see a (f) I'll say that I actually use a milage computer
> thingy
> >I got from a gas station. It takes liters or US gal and miles or
> kilometers
> >and gives you liters per 100k or miles per gallon. Besides I did get above
> >twenty-two several times in the States when I stayed above 3500 but below
> 3800
> >RPM, unca Joel's advice. I had to have at least a tailwind a somesort.
> With a
> >wind it would run below 22 MPG.
> >
> >I put 47,000 miles on this thing in 18 months so I kinda nailed this down.
> I
> >feel that I'm pretty close to the numbers also. I earned my Instrument
> >Helicopter Rating over 20 years ago and feel that I can get fuel
> consumption
> >right close.
> >
> >Anyway, I didn't mention that I run Prolong in the xsm, differential and
> the
> >engine. Plus I run a Gulf Coast submicron filter system. Add to that ,
> this
> >van seems to sit low, I personally think the springs are just sagging.
> I've
> >also really nailed down a good wheel alignment. The tech said my rear
> >adjustment is maxed on account of the springs being sagged somewhat. I took
> his
> >word for this. Anyway the lower the better in my mind for MPG.
> >
> >Hope to hear from you.
> >
> >Gas Milage Serious for Years.
> >
> >Mark Keller
> >91 Carat WLE
> >
> >Marshall Ruskin wrote:
> >
> >> One must make certain one is not mixing Imperial gallons (Canadian
> gallons,
> >> about 20% bigger, seriously), with US gallons, when one makes
> comparisons.
> >>
> >> Marshall Ruskin>I have a 1991 Carat WLE automatic with a Canadian rebuilt
> >> with 80,000 miles.
> >> >I'm in the land of 90K per hour, so that about 55ish. I get 22 MPG or
> so.
> >> >Sometimes close to 23 other times just above 21. When I run the air
> >> >conditoning it stays about 1 to 2 MPG lower.
> >> >
> >> >If all I do is drive in the City I get 19 MPG regardless of what is on
> or
> >> how
> >> >much load.
> >> >
> >> >We normally have the two kids and my wife and I, and most time the dog.
> So
> >> >our payload is around 700 lbs. The title says the vehicle's weight is
> 3425
> >> >lbs. I run 205 Firestone PR 440's. Not a tire I'd buy again, not round
> >> >enough for me. But my milage was the same with the last set of tires
> too.
> >> >
> >> >
> >> >
> >> >Bill wrote:
> >> >
> >> >> We don't do better than that with our '81 auto Westy. 14 is about it.
> >> >>
> >> >> At 01:44 AM 12/29/99 EST, Charles Hokanson wrote:
> >> >> >Are all these numbers for manuals? I am only getting 14+ in my
> >> automatic.
> >> >> >Charlie.
> >> >> >
> >> >> Bill (SE Arizona) (Bill@freeholder.com) HTTP://www.freeholder.com
> >> >> ----------------------------------------------------------
> >> >> Censorship is the assassination of ideas. No matter how well-meaning
> its
> >> >> proponents may be, they are more dangerous to us than any outside
> enemy.
> >> >
> >
> >
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