The issue is not how large the tank is but how stabile and dangerous the
gasoline is. Gasoline contains many different chemical species. Some of
these species are olefins which over time tend to polymerize and form gums
that can plug small orifices like fuel injectors. Reactions of olefins or
other species known as diolefins can also react with oxygen to form various
types of acids. It is difficult to keep oxygen out of the tank because of
the slight expansion and contraction of the gasoline with temperature. A low
and constant temperature will tend to inhibit the polymerization as well as
preventing the tank from breathing. I would say that keeping gasoline stored
for over 3 months will start the polymerization process. If you have ever
had the opportunity to smell gasoline that is quite old ( a year or two) you
will notice the sharp rancid smell, those are acids and other bad actors .
It may also be against environmental rules to have an underground storage
tank in your area. Be sure if you put in the ground (if it is in the air
temperature variation could be 20 degrees or more between night and day) it
is held down firmly because in the event of ground water build up it may pop
out of the ground and may even rupture.

In my opinion even if the fuel mileage for cars were to double in the next
three years and the price of gasoline was $4 a gallon the savings you might
realize is not worth the risk of storage nor the damage to that brand new
high efficiency automobile you just spent several thousand dollars for.
Don't forget to account for the amount of interest you might realize if you
took the money you spend for the 500 gallons of gasoline now and instead put
it in the bank to realize some interest compounded over 3 years.

On the point of danger - gasoline has about 15 time energy per pound than
dynamite. Since gasoline weighs about 6.5 pounds per gallon the 500 gallons
will have the equivalent energy of over 45,000 pounds of dynamite. It is
true it may not be released as suddenly as dynamite but be sure an put the
500 gallon tank far away from anything you might not want to damage and
especially far away from any potential sources of ignition.


"Bob La Londe" wrote in message
...
"Pete C." wrote in message
ter.com...

Bob La Londe wrote:

"Karl Townsend" wrote in message
...
I'm thinking of getting a large gasoline tank, enough for two or more
years of use. Looking at the stabil product, they claim increasing
fuel
life (in an engine) to 15 months.

Are there other things to increase fuel life? For example, will
storage at
a constant 45 degrees help? What problems will old fuel cause?

Karl

I think there is a limit regarding storage and a step up in regulations.
Something like 500 gallons takes minimal precautions etc. Never really
thought about it, but I know a lot of the farmers in the midwest have a
500
gallon tank for their tractor(s), and I think most of them used to just
sit
on stands. Been a while and I never really asked.

My grandfather had an elevated gasoline tank on his farm for filling his
tractor in Ohio. I know most of his gentleman farmer buddies did too.
Don't recall if he ever said how big it was, but I would guess 500
gallons.