Left Coast Mogas (Ping! Jim Weir)

There seem to be few places in California where MOGAS is still legal.
Most of California requires additives to automotive gas that the FAA
explicity prohibits under any STC.

-Robert

Mystery solved. Modesto gets its mogas (don't call it auto gas any more
says the distributor) from an outfit called Boyett Petroleum in Modesto.
Anybody can get it from the refineries over in the Bay area or from Reno, no
problem. It is just that it is illegal to use it in automobiles, but
perfectly legal in off road vehicles. All California highway vehicles are
restricted to a 5.5% gasahol mixture or diesel.

Repeat, ANY DISTRIBUTOR can get pure mogas from the refinery in 8000 gallon
lots if they want it in California. Now the problem seems to be convincing
a few airports to go through the hassle to get it in small quantities so
that it doesn't sit for six months and break down.

Jim




"Robert M. Gary" wrote in message
ups.com...

There seem to be few places in California where MOGAS is still legal.
Most of California requires additives to automotive gas that the FAA
explicity prohibits under any STC.

I wonder if the small quantities will cause the price required to cover
the overhead of the tank, etc more than the price of the higher volume
100LL? When I had the Aeronca Chief (65hp cont) the engine ran MUCH
better on MOGAS than 100LL. The automotive detergents helped keep the
engine clean along with the hotter burning lower octane.

-Robert

Robert M. Gary wrote:
I wonder if the small quantities will cause the price required to cover
the overhead of the tank, etc more than the price of the higher volume
100LL? When I had the Aeronca Chief (65hp cont) the engine ran MUCH
better on MOGAS than 100LL. The automotive detergents helped keep the
engine clean along with the hotter burning lower octane.

What makes you think the lower octane burns hotter?
How does the difference in octane additive make the fuel burn hotter?

On Tue, 21 Jun 2005 02:35:08 GMT, john smith wrote:

Robert M. Gary wrote:
I wonder if the small quantities will cause the price required to cover
the overhead of the tank, etc more than the price of the higher volume
100LL? When I had the Aeronca Chief (65hp cont) the engine ran MUCH
better on MOGAS than 100LL. The automotive detergents helped keep the
engine clean along with the hotter burning lower octane.

What makes you think the lower octane burns hotter?
How does the difference in octane additive make the fuel burn hotter?

Some people insist low octane fuel burns FASTER, which might put more
heat in the cyl - but I have seen info from fuel engineers
thatndisputes this theory.

The Cubs at Hampton NH airfield were STC'ed for mogas when 80 octane
became unavailable. The general feeling was that the engines had a
tendency to stall in cold weather. (They certainly did have such a
tendency, whatever the cause.) Furthermore, the instructors didn't
like the smell of it (the instructor sits in the front seat of a Cub).

Hampton still sells mogas (at one point it was cheaper on the field
than at the gas stations all around) but the STCs have been removed
and the Cubs run on 100LL.


-- all the best, Dan Ford

email (put Cubdriver in subject line)

Warbird's Forum: www.warbirdforum.com
Piper Cub Forum: www.pipercubforum.com
the blog: www.danford.net
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wrote in message
news
On Tue, 21 Jun 2005 02:35:08 GMT, john smith wrote:


Some people insist low octane fuel burns FASTER, which might put more
heat in the cyl - but I have seen info from fuel engineers
thatndisputes this theory.

I was always told the higher octane burns faster, and is consumed in a
shorter duration, thus a lower temperature.

Allen

Allen wrote:

I was always told the higher octane burns faster, and is consumed in a
shorter duration, thus a lower temperature.

Other way 'round on the burn rate. From a motorcycle performance site -

"The higher the octane, the slower the speed of the burn; the lower the octane
the faster the burn. If the burn is too fast, uncontrolled combustion can
occur. This most often is heard as “pinging” and is commonly referred to as
detonation. This is because instead of burning through top dead center of the
combustion stroke, the entire charge is ignited too early and explodes in the
chamber and acts as a bomb. Conversely, if the speed of the burn is too slow,
it continues after the useful work can be done in the motor and manifests itself
as poor throttle response, reduced power output and increased emissions and fuel
consumption. An engineering fact: THE MOST HORSEPOWER IS MADE AT THE THRESHOLD
OF DETONATION. We have often gained horsepower on the dyno and felt improved
starting and driveability going from Premium grade gas to Regular. This change
was recently quantified in a customer’s Ducati M900 by reducing the cranking
time to start-up from 15 to 3 revolutions, although part of the improvement is
explained below."

George Patterson
Why do men's hearts beat faster, knees get weak, throats become dry,
and they think irrationally when a woman wears leather clothing?
Because she smells like a new truck.

wrote:

Some people insist low octane fuel burns FASTER, which might put more
heat in the cyl - but I have seen info from fuel engineers
thatndisputes this theory.

Higher octane fuel is used to make the flame-front advance more slowly and
smoothly across the combustion chamber, thus eliminating "knock". The flame
starts at the spark plug and fans out from there. What you want is less of an
explosion, and more of a steady increase in pressure in the combustion chamber.
That's what higher octane does.

Disclaimer: not a professional in this field.