Let me rephrase, does anyone know if BMW oil is Group 4 or 5, or Group 3? (I'm guessing 3)
"Did you know that 80-90% of an engine oil is Base Stock? The rest is made up of Additives. So to be the best synthetic, you would think you would need to have the best synthetic base stock as a start.
Particularly PolyAlphaOlefins (PAO – Group IV), Esters and utilization of Alkylated Naphthalene’s. (Group V). These were the original synthetic base stocks as tailor made from building blocks using chemical processes to create the “perfect” oil molecule.
However, hydrocracked base stocks (Group III) can nowadays also be marketed as synthetic but are still mineral oil based."
https://bestsyntheticoilguide.com/sy...synthetic-oil/