Joel,
Interesting comments and records.

When in Alaska I learned an interesting bit about fuels.

I had a cousin that worked for Union Oil. His job was to receive fuels
from the
Tesoro refinery down on the Kenai Peninsula about 100 miles away. The
refinery
sat right on the edge of Cook Inlet and got its crude directly from the
offshore
oil rigs out in the Inlet via underwater pipelines direct to the plant.
There
was a single pipeline  that went  from the Kenai Tesoro plant to
Anchorage.
Every gasoline company in Anchorage...Shell, Texaco, Chevron, Gulf,
Standard,
Tesoro, and independents got their fuels from that cracking plant. And
they were
the same basic grades of fuels.

>From my cousin, I learned that each time a specific fuel was pumped, the line
was cleared with an air  charge and then the next lower grade of fuel
was put
through. The first arriveing fuel after the air charge was always
contaminated.
The air never completely cleared the line and in a 100 mile longe pipe
there
still was enough fuel from the previous load that the residual would
contaminate
the first of the next incoming fuel. Eventually newly arriving fuel
would flush
the line clean. He would drain a certain number of barrels of fuel from
the
line  as the next charge of fuel would come through, and test to be sure
when
all the contaminated fuel were clear of the pump head and he was pumping
clean
fuel of the next grade.

Pumping would begin with the highest octane aviation fuels and finish
with the
lowest grades of refined oils, like fuel oils. In Alaska in winter
turbine type
aircraft, diesel trucks and stove oil was virtually the same......Arctic
Diesel.
The peculiarities of operating in that cold environment required an oil
fuel
which as it happened would work in all three types of equipment.

Because of the method of pumping there were a goodly number of barrels
of
perfectly usable slop fuel, but it wasn't the specific octane that was
sold at
the pumps. It was a mix of a higher and lower octane... blended as it
were, and
was not legal to sell. So employees and company personnel made personal
use of
it. Depending on what fuel it was, diesel, heating oil, gasoline, etc,
it was
used in company cars, personal cars and trucks, and outboard motors,
etc.

At the time, all fuels from the plant were handled the same way by all
the
companies in the area. The various fuels were pumped to the various tank
farms
as basic fuels, and each company put in their own unique additives at
their own
tank farm.

>From this experience I realized, like the little boy sez " There ain't a hair's
difference between 'em", where fuels are concerned.

Modern fuels are engineered(chemical/petroleum engineers) to certain
specifications in order to be utilized by the many engines being built
by the
automotive industry. Those specs may be a bit broad due to the wide
range of
engines employed, but I suspect it is still mostly standard specs.

My $0.02!

John Rodgers

Joel Walker wrote:

> > Do we notice a increase in fuel economy when we use higher octance fuel?
> > A power increase? Any increase? well besides cost obviously.
> > I use 92 octane 76 fuel consistently, for me it makes a difference, the
> engine makes more power, smoother too.
>
> i've been keeping close records on my 88 bus since i bought it new. six
> brands of gasoline and three octanes. as far as i can tell, there ain't a
> nickel's worth of difference in the brands or the octanes. that is, 87
> octane gets just as good mpg as 92/93. only when you calculate the
> miles/dollar do you see the difference! and the higher octanes get lower
> mpd. :(
> if you like, i can send you the raw data or the processed "report" (dippy
> little thing written in REXX).
>
> but that's MY bus with MY driving style(s) in MY region, using the gasolines
> blended and sold hereabouts. other regions and other gasolines may (and
> probably will) vary. and you can't count on Shell gasoline actually being
> "Shell" ... i've seen Exxon and Amoco and Texaco trucks filling up the Shell
> stations around here ... which is probably why the gasoline brand doesn't
> seem to matter. :(
>
> joel
> oh, what the heck .... here's the brand comparison. :)
>
> brand     octane  tanks gallons    cost        miles       mpg  $/gal
> miles/$
> Amoco    R87     46    592.0     654.38   12,077.3  20.4  1.11  18.46
> Amoco    R89     23    300.2     343.26     5,774.0  19.2  1.14  16.82
> Amoco    P92     23    305.8     395.49     6,111.8  20.0  1.29  15.45
>                           92  1,198.0  1,393.13  23,963.1  20.0  1.16  17.20
>
> Bp       R87        46    574.5     627.48   11,577.0  20.2  1.09  18.45
> Bp       R89        23    313.6     367.39    6,231.3   19.9  1.17  16.96
> Bp       P92        25    308.9     397.89    6,139.3   19.9  1.29  15.43
>                          94  1,197.0  1,392.76  23,947.6   20.0  1.16  17.19
>
> Chevron  R87     45    604.6     668.75   11,984.0  19.8  1.11  17.92
> Chevron  R89     23    295.6     355.33    6,042.9  20.4   1.20  17.01
> Chevron  P92     24    304.1     399.03    6,175.9  20.3   1.31  15.48
>                           92 1,204.3  1,423.11  24,202.8  20.1   1.18  17.01
>
> Exxon    R87      46    617.5     679.13   12,270.3  19.9  1.10  18.07
> Exxon    R89      23    297.8     345.06    5,655.4   19.0  1.16  16.39
> Exxon    P92      24    302.3     389.09    6,205.6   20.5  1.29  15.95
>                          93  1,217.6  1,413.28  24,131.3   19.8  1.16  17.07
>
> Shell    R87       45    581.6     644.01   11,317.3  19.5   1.11  17.57
> Shell    R89       23    301.6     353.11    5,997.0   19.9   1.17  16.98
> Shell    P92       24    311.9     392.46    6,338.1   20.3   1.26  16.15
>                         92 1,195.1   1,389.58  23,652.4  19.8   1.16  17.02
>
> Unocal   R87     43    580.1     618.57  11,418.2  19.7  1.07  18.46
> Unocal   R89     21    269.1     311.73    5,332.1  19.8  1.16  17.10
> Unocal   P92     21    274.1     349.98    5,581.4  20.4  1.28  15.95
>                         85  1,123.3  1,280.28  22,331.7  19.9  1.14  17.44
>
> Z-other  R87      2     27.0      28.62      533.6  19.8  1.06  18.64
> Z-other  P92      1       3.5        4.28        55.6  15.9  1.22  12.99
>                          3     30.5       32.90      589.2  19.3  1.08
> 17.91
>
> Z-start  R87      1     15.7      14.10        0.0   0.0  0.90   0.00
>                          1     15.7      14.10        0.X-Mozilla-Status: 0009>
>                            7,181.5  8,339.14  142,818.1