Date: Sat, 28 Mar 2015 10:11:53 -0700
Reply-To: Don Hanson <dhanson928@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Don Hanson <dhanson928@GMAIL.COM>
Subject: Re: Load vs fuel consumption..
In-Reply-To: <BAY405-EAS56B0F16435E071C479C7E0A0F70@phx.gbl>
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I was surprised to discover there was that much difference in fuel
consumption when I switched over to use up a few tanks of premium gas,
while recording every mile, using an app called "Fuelly" on my smart phone.
It confirms the figures. Now, after about 4 months and ~ 20k miles
driven since I switched over to premium gas most of the time, I can
quantify a couple of miles per gallon improvement in gas consumption .
As I was tuning my inline hybrid motor I could NOT detect any knocking
at all, even when I was abusing the motor with high loads and low revs to
see if it was knocking....However, the Gurus at Techtonics Tuning told me
that I *should* burn premium because this particular combo of ABA and
8-valve head results in a high compression engine...Obviously, they know
what they are talking about....
Yes indeed, the speed at which you drive does make the most difference in
fuel economy, especially in our square vanagons, but true for every
vehicle. I also have another van, an AWD Safari that I bought for the
traction and to use for work....I record fuel consumption in that one also,
and at around 70mph I get 14mpg and at 55 it gives me around 18mpg. That
Fuelly app is handy as it records a lot of data for you with just a few
keystrokes while at the gas pump....It's got a function to figure your cost
per mile....The Vanagon clocks in (averages) at $13.5 cents per mile, the
Safari AWD costs $17.5 cents per mile...for gasoline only, of course.
On Sat, Mar 28, 2015 at 9:13 AM, Dennis Haynes <d23haynes57@hotmail.com>
wrote:
> Actual overall speed along with wind conditions probably have more of an
> overall effect on fuel economy than carrying weight. As for the knock
> sensor compensation enough for a fuel economy change during extended steady
> stat cruising, not accelerating or hill climbing could be an indication of
> that engine, gearing, and load combination really working at the limit of
> both efficiency and the edge of destruction. Over the years I find it
> common to get differing fuel economy on trips based on direction,
> especially when mountain ranges are involved. Outside temps can also mean a
> difference. Colder air is denser air and you need more energy to push
> through it. It also takes ~30% more fuel to push a vehicle at 70 mph
> compared to 55 mph so speed changes and traffic conditions can make huge
> difference on the trip. I'm just not sure the weight difference alone
> accounted for the mileage difference.
>
> Dennis
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
> Of Don Hanson
> Sent: Thursday, March 26, 2015 11:25 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Load vs fuel consumption..
>
> My 84 tin top with a westie interior and an inline ABA Jetta motor driving
> though a 5sp manual shifter: I just recently completed another winter
> sojourn to the Southwest US. On my return trip along the east slope of
> the Sierra Nevada range, near San Diego to Near Portland, Or...My normal
> fuel economy went down, as I expected, because I was loaded to 4900lbs,
> weighed on an ODOT highway scale, with half a tank of gas...I dropped from
> average of 24.xx to about 22.xx mpg, driving at my normal cruising speeds
> of 55-70mph....
> Just today I found another ODOT scale turned on but unattended and
> weighed again, without my tools and camping gear aboard for a 2 month
> trip......4100lbs....again with half tank, me and my big dog aboard....I am
> back to about 24.5mpg average....So that approximately 800bs of tools and
> camping gear uses 2mpg to haul around....The ODOT scales are only accurate
> to about 100lbs...so
>
> For those who might be considering one of these "hybrid" ABA/1.8 liter
> motors, like the one that I stuck together in my van, about 50k miles ago,
> the fuel of choice is indeed premium fuel with a decent octane rating....I
> was told, by Techtonics Tuning as they helped me with parts and
> specifications for exhaust, etc etc....I was told this particular combo of
> an 8 valve head on an ABA block results in a pretty high compression ratio
> and that I should run premium gas...I did some experiments with premium and
> regular....the regular burns less effectively....I think the knock sensor
> must be working overtime on regular gas but with premium, all is sweet
> inside and I get an estimated 1-2 miles per gallon better gas mileage and
> have substantially more torque and high rpm power...
>
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