"Apparently" - From numerous sources. AKA, not reliable. Shell, Caltex, and a couple of others (7/11's, woolies etc) run out of a separate refinery than BP and Mobil. A family member worked in a chem lab at one of the refineries and said he would never buy fuel from the shell/caltex etc stations if he could avoid it (bad quality compared to the BP refinery) BUT that being said, it depends on the location. For example if there's a BP fuel station in the middle of nowhere, where surrounding towns are all shell/caltex, then chances are they're contracted fuel from Shell/Caltex, rather than from BP. So really ignore everything I just said, a lot of people say V Power is the go. A lot of people say BP Ultimate is the go. I'm a BP Ultimate man myself, but go test them out yourself. PS. The additives in the BP fuel are boss.