Originally posted by: Marlin1975
Originally posted by: gorcorps
Originally posted by: Linflas
Whatever is cheapest, currently Costco for me. Gasoline is gasoline, the idea of caring what brand it is seems silly to me.
Some really cheap ones are watered down. My car stalls quite a bit on shitty Mobil gas in my area but bp and Marathon run great.
The gas is not. Maybe some bad tanks/filters at that station, but the gas is the same. Notice how the same truck that fills up one place also fills up others with different names?
That same truck may be making multiple stops at the terminal in between dropping off loads, plus those trucks have separate internal tanks. That allows them to haul multiple types of fuel (regular, premium, etc).
Gasoline within a given region is a fungible product. That means that any one refiner's gasoline of a certain grade is blended to meet or exceed a standard set of specifications on qualities like octane, distillation profile, vapor pressure, drivibility index, vapor lock index, etc. As you move around the country and as the seasons change, these specifications change. For instance, Chicago and other major metro areas have a VOC emissions spec the gasoline has to meet in the summer, but not in the winter. Winter gasoline up north is very different from summer gasoline in the south, and California has a completely different set of specs relative to the rest of the country.
So, while all gasoline within a given region must meet the same set of standards, gasoline from one refinery isn't necessarily identical to gasoline from another refinery. There are many different materials produced by a refinery that get blended into gasoline, and different refineries produce different qualities and quantities of these materials. For instance, a refinery that processes predominately light crude will tend to have more reformate to boost octane, while another refinery that processes mostly heavy crude will tend to have more catalytic cracker naphtha to blend off. While the product from these two refineries will meet or exceed the specifications set down by law, chemically these two gasolines will be different.
The most important difference between gasoline brands, (and branded vs unbranded) is the additive package. A baseline additive package is added to gasoline before it is shipped by every refinery in order to meet some of the standard specifications (corrosion inhibitor for example). When this gasoline ends up at a terminal, it is loaded onto tanker trucks. If it is going to a generic gas station, very few additives (or none at all) will be added to the load. However, if it going to, say, a BP station, then BP's additive package will be added to the load. Later that day the same truck/driver may load the same material out of the same tank at the terminal, but instead add Shell's additive package for delivery to a Shell station. This is where you will see a major difference in the gasoline you buy...
It is funny... I see so many people that are "picky" about their cars spend a bunch of money on products for their car, whether it be for the exterior, interior, or engine/power train, but then try to save 5 or 10 cents a gallon by purchasing the cheapest gasoline they can find from the no-name gas station. Products like synthetic motor oil, good quality fluids, and specialized air filters, spark plugs, etc, may be great for your car, but think about the one fluid you put in your car on a regular basis... gasoline. By spending a little more money on a branded gasoline (like BP, Shell, Exxon, Valero, Chevron, etc) you will get a better additive package that will help keep your fuel system clean.
I buy Exxon or Mobil gas because I get a discount. I used to buy BP gas (I used to work for BP), and they make a good product and have a very good additive package. BP inherited Amoco, and Amoco really took pride in their fuel quality. In all honesty, I like Shell V-Power the best, and Chevron's Techron additive is actually recommended by auto manufacturers to help clean up dirty fuel systems.
R <-- Works at a refinery, not speaking on behalf of his company