Some people say the refining process and Octane levels are all standardized and regulated.
(I don't know this for fact, but it made sense..)
I don't know anything about additives, but I think what every you use, consistancy is the key.
Fuel consistancy really depends on your area..
In Denver, we have 3 local refineries..
Conoco, Brand-X, Brand-Y...
All Conoco gas stations in Denver, are required to fill their underground tanks by calling Conoco for deliveries..
BP, Shell, Amaco, Phillips66, 7-11, Circle-K, Qwik-Mart, etc., all order their
fuel deliveries, from the guy who is the cheapest
that day..
...so even if you go to your local Exxon station in Denver, you are NOT getting Exxon refined fuel.
Exxon doesn't have storage tanks in Denver.
You might get the Exxon additives that the delivery guy dumps in the tank, but that's about it.
From a political view, I've read that certain petroluem companies extract from specific areas of the world.
- Exxon - Arab Oil
- British Petroleum - Arab Oil
- Shell - Russian Oil
- Conoco - Alaska & Gulf of Mexico
- Synclair - Continental US, (Texas, Oklahoma, Wyoming, Montana, Nevada)
- Chevron - Canada & Mexico
(I know I've missed some and I'm trying to do this from memory, so I'm hoping someone else has seen this list and can verify it.)
Now some would say, "Use up that Arab Oil first",
while others would perfer we "Boycott Arab oil",
and most people just, "buy what's cheapest or closest for me"
That is for each of us to decide.
If you want consistancy, ask your local gas stations, who they buy their gas from?