GONNA CHANGE OIL ,APPRX 3000 MILES,CAN I RUN SYNTHETIC NOW,THINKIN ABOUT ROYAL PURPLE,IS IT WORTH IT.
Amsoil is the best, after all they invented synthetic oil!!!!
My understanding is mobil 1 EP is part base 3 and part base 4. Still a good oil, but not 100% base 4 like the european car oil.Any base 4 synthetic (Mobil 1 EP, Royal p, Amsoil ). I use Mobil 1 extended performance. Mobil 1 synthetic non EP line is a base 3 stock as with others like Castrol, Valvoline etc.
Give Quaker State Q Ultimate Durability Full Synthetic a try. In my 350z I was getting 3/4-1 MPG more with the Quaker State then with Mobile 1 or Royal Purple. That is what i plan on running in my Coyote Crate Motor after the first or second oil Change. The 350z has around 130,000 miles so i changed it every 5,000. Also in SW Indiana it is about $1.50-$2 cheaper than the Mobile or RP