100% Synthetic vs Full Synthetic Before 1998 the term “100% Synthetic” meant that the base oils by regulation had to be Group 4 and 5 “Synthetic” Base Oil. This is because Groups 1, 2 & 3 were classified as “Conventional” Mineral Base Oil. Over 50 years ago AMSOIL was the First to develop an API-rated 100% … Continue reading Learn about 100% Synthetic vs Full Synthetic motor oil – Base Oil Groups Defined