I normally fill up at a name brand gas station; Shell, Marathon, BP, etc.

One of the closet to my home and even more important a big parking lot for access with a trailer is a Speedway.

I think the tanker trucks all get filled from the same piepline, but then they may dump in a barrel of this or that additive.

I have heard that the same guy or company may own 3 or 4 different brands of stations in the same area. Same gas or different?

Lastly at Marathon's around here 89 oct sells for same price as 87 oct. So why not, right?

It all comes from the same refinery.

hmm ... personally I have always purchased fuel from name brand stations .

with my turbo and blower cars, sometimes if i fuel from certain stations , ill experience some detonation . also, in my diesels , some stations have water in the fuel.

Ive always had great luck with Amoco fuels and shell V-power. So i stick with those.

i cant honestly tell you if theres a difference in the actual fuel ... but i trust the more reputable stations to actually put 93 in the 93 tank ... and not allow water to get into the diesel.

Mobil would have you believe their additive package is the reason they are always 4-8 cents higher than the no names. I have to believe there is something to it, to help keep your fuel system and combustion chambers cleaner, although I use the cheapest I can find...

My Dad had a Marathon station years ago. Marathon owned Speedway - same gas but cheaper because you pumped it yourself.

Every major petroleum company has a trading department. They buy and sell fuels based on their own demands. They also use it as a profit center. Sometimes you have too much and it's a bad thing- like when the market dips. Sometimes you have too much and it's a good thing. Sometimes it's more profitable to sell it wholesale- there may be more margin in selling a load that's still on a boat rather than incurring land transit costs. Sometimes your competitor might have plenty of inventory but maybe a pipeline problem- the fuels in your local tanks just got way more valuable to him.

Relatively speaking, gas is gas. With all the different EPA mandates, there may be quite a few locally-specific formulations but if it meest the spec, it meets the spec.

I buy all my gas at WaWa. They are the cheapest around, never had ANY issues.

Gas is traded on the market. Refiners specs vary amoung each other. Places like WaWa usually have the minimum additives, (ie, rust inhibitors, vapor pt ect.).
It leaves the refinery and gets pumped to a local terminal where things like ethanol and extra additive packages are added.
What does this mean? GENERALLY speaking, most of the gasoline, no matter what the brand name of the station, came from one refinery. That's how gas gets traded.
DAVE

Same refinery does not mean it has the same additive package. Some of the gas out there is crap. About two years ago, GM and Ford stopped just short of recommending particular brands, probably because they feared lawsuits. The problem was excessive engine deposits. The concensus was this:

Top Tier: Chevron
2nd Tier: Mobil, Shell

Michael

It all comes from the same refineries. The beter brands put more or better detergents (additives) in their fuel. I have always preffered Shell and stayed away from Marathon.