Quote Originally Posted by MajesticBlueNTO View Post
Almost all Mobil1 SuperSyn (including 5w20) is a Group 3 synthetic. As well as any Castrol Syntec that is not 0w30.

The Extended Performance Mobil1 should be a Group 4, and if you can find any old stock of Mobil1 0w20.

Group 4 syns are limited to your boutiques (Amsoil, Redline, Royal Purple, Nippon, etc), Castrol Syntec 0w30 (German Castrol), and Esso XD-3 Extra 0w30 and 0w40.
I don't believe that's entirely true; Mobil1 5w-20 with SuperSyn is a Group 4 (PAO) synthetic, if you want to get technical not all of the grades of oils those other brands sale are true group 4.Most of the brands you mentioned are group 5 synthetic ester based oils, that is the only difference.All I really care about is that Mobil1 with SuperSyn passes the ILSAC GF4 Performance standards! ....that's good enough for my needs and probably most here unless they plan on racing.


_3