This topic comes up repeatedly on here and I've noticed it's even in the shout box. No one knows for sure what any brand of synthetic contains. Even Amsoil's 5w-30 could potentially use some Group III. If it's majority PAO, they won't even mention other base stocks. It's pointless.
From the Japanese Mobil 1 Website:
15w-50 - PAO
0w-40 - PAO
0w-30 - PAO
0w-20 - PAO
5w-30 - PAO + Hydroprocessed
10w-30 - " "
How one defines synthetic varies. Only Mobil 1 5w-30 "Extended Performance" was tested and showed Group III. Also contained Group V.
From the Japanese Mobil 1 Website:
15w-50 - PAO
0w-40 - PAO
0w-30 - PAO
0w-20 - PAO
5w-30 - PAO + Hydroprocessed
10w-30 - " "
How one defines synthetic varies. Only Mobil 1 5w-30 "Extended Performance" was tested and showed Group III. Also contained Group V.