Date: Sat, 26 Sep 2009 16:55:10 -0400
Reply-To: mcneely4@COX.NET
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dave Mcneely <mcneely4@COX.NET>
Subject: Re: [WetWesties] Gas Mileage
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Extensive, very carefully controlled studies yield test data that
support that slower speeds yield greater fuel economy (no, I don't have
the studies at hand for citation, but the EPA web site fueleconomy.com
might list some of them).
To relate a recent experience, and to keep the vanagon content:
On my 5000 mile trip this summer ('91 Vanagon GL Campmobile four speed
manual transmission), I kept careful records. Recently completed (in
the two weeks prior to the trip) all tune up components, and a new AFM).
My legs, averaging 209.6 miles, yielded from 17.26 mpg on I-40 in
Oklahoma and Texas, driving around 65 mph in stiff side winds on almost
level (but climbing from the "low rolling plains" at around 1200 feet
elevation to the High Plains at 3500 to 4300 feet elevation over a long
distance) with luggage in the top carrier (took it down and put it
behind the rear seat) up to 23.20 mpg in the Uinta Range in Utah on two
lane roads with a great deal of up and down, driving from 45 to 65 mph
depending on grade. Note that the low speeds were uphill and usually in
a lower gear. Overall average was 20.56 mpg for 4894.4 miles. Three
legs exceeded 23 mpg, and four were under 19 mpg (one of which was the
17.26 mentioned above). Wind was involved in all the very low mpg
specimens. I would consider my van to have been moderately loaded, with
two small adults, camping gear, and luggage.
Tires (195R14C) were inflated at the VW recommended 43 psi front, 53 psi
rear cold. Elevation did seem to improve the mileage. Does anyone know
how much the tires expand as elevation increases? Does this create a
rounder profile on the tires, and thus increase mpg but also increase
tire wear? Oh, when I drove where the posted octane rating on the pump
was 85 or 86, I bought midgrade fuel at 88 or 89 octane. Don't know
what that means for fuel economy, and have been (almost) since convinced
that it was probably a waste of money.
Dave Mc
On Sat, Sep 26, 2009 at 2:33 PM , Karl Wolz wrote:
> Not to argue against the laws of physics, but ...
>
> Last weekend drove from Phoenix up to the Hubbel Trading Post NM.
>
> Phoenix (1500 ft.) to Winslow, AZ (5000 ft.) - 198 mi. - mostly 75mph
> except
> a few construction zones - 20 mpg.
>
> Winslow - Hubbel - Winslow - 250 mi., half on Indian Reservation @
> 60mph
> (hilly) - 17.5 mpg.
>
> Winslow - Phoenix (with a side trip to Prescott Valley) - 230 mi. -
> Mostly
> 75 mph. - 21 mpg. (elevation decrease on this leg).
>
> My experience over the years has been similar to this. Unless pushing
> into
> a severe headwind, I get right about 20 mpg. Doesn't seem to matter
> the
> speed. Can't explain it, and I don't have arduous records to prove
> it, but
> it seems to be the way it is.
>
> '85 Westy w/ 2.1L, 2.1 exhaust, & digifant; Stock sized tires, and
> .077? 4th
> gear. Back when it had the 1.9 and stock gearing, I had similar
> results.
>
> Karl Wolz
>
>> So
>> guys and gals, if you want to save some gas, slow down.
>>
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