I don't know.....take for granted that GTX is the biggest market share for Castrol, for which Amsoil is after, but is Synpower Valveline's largest selling product? Is PP Pennzoil's largest? Amsoil did not say on what principle the competing oils were selected.
Originally Posted By: ericthepig
Agree with demarpaint, GTX has a big following (I was a user in the '80s), Syntec not so much, and Edge just came from the refinary.