Do your motor oils contain zinc/phosphorus?August 17, 2018
Is a special oil filter required when using Royal Purple?August 17, 2018
Yes. For stock, non-performance valve trains, Royal Purple API-licensed oils (API SN and ILSAC GF-5 licensed) are OK. For upgraded performance flat tappet camshafts, and vintage high performance engines, we recommend our HPS or XPR engine oils. For a specific recommendation, contact our tech department at 888-382-6300.