Quote Originally Posted by vs2306 View Post
Is there honestly a difference between the two? Racing 10 is about $35 more at supercheap auto. But at the end of the day they're both 10W40 full synthetic.
While they are both good, they are not the same.

The cheaper "full synthetic" is a group 3 base oil, it's made from crude oil, Group III base oils are sometimes described as synthesized hydrocarbons, or hydrocracked, it's fake synthetic so to speak.

Group 4 base oils are polyalphaolefins (PAOs)
Group 5 base oils are classified as all other non-petroleum oils, such as polyester and esters.