Originally Posted by Dadio61
I couldn't disagree more. I worked for a company that had 2 accounts for our equipment back in 2000/2001. I averaged 60,000 miles per year in my company truck, and the difference in fuel quality was obvious. I would easily get 60 or 70 miles per tank more from the good fuel supplier.
Faustus is correct that the main difference between different gas brands is the additives that are added. The government has set guidelines for the amount of additives that need to be in the gas; some brands do the bare minimum while others add 4x the amount required.
The thing with refineries too is that just because refinery brand X processed/refined the gas, it doesn't mean when that tanker leaves the plant that it's going to brand X gas stations. Branded gas stations do buy gas from competitor refineries. Then places like Costco and other supermarket gas stations, when they fill up their tanks, they usually buy whatever gas distributor was the cheapest that day. The supermarkets very well could have contracts but more or less, it's a roll of the dice of who's gas your are actually using.
Since all this branded gas is mixed between multiple gas stations, the gas stations create their own product by adding of the additives. So when you buy gas, you're buying the brand name and their additives. Supermarket gas tends not to have any additives.
60-70 miles extra is a huge difference in my eyes and that's awesome you could get that. The thing with talking about fuel economy of different gas blends, it's really difficult. There are tons of factors that go into fuel economy - ethanol content, weather conditions, did the gas station switch season blends yet, user throttle response, the list goes on, haha.