MAXIMA SEMI-SYN is compatible with petroleum and synthetic engine oils. SEMI-SYN is a fully formulated race oil and does not require the addition of additives or boosters. No special procedures are required when changing to Maxima Racing Oils. NOT RECOMMENDED FOR STREET USE. MAXIMA SEMI-SYN race-grade formula has elevated anti-wear additives designed to protect engines in extreme conditions. Elevated antiwear additives may adversely impact emissions systems on passenger cars.