Red Line 50WT Race Oil (15W50) - 1 Quart 10504 | Used in applications with wider bearing clearances. Popular with sprint and midget applications on methanol -- offers less frequent oil changes due to less fuel dilution. Reformulated for improved frictional properties. Special detergents for improved lubricity and less detonation. Polyol ester base stocks provide more stability and film strength when exposed to excess fuel dilution. Each of these products has no less than 2200ppm of zinc and phosphorus for antiwear. Each race oil product is a multi-grade, offering 2-4% more power than oil of a similar viscosity - 20WT is a 5W20, 30WT is a 10W30, 40WT is a 15W40, 50WT is a 15W50. Improved protection at startup, lower oil temp, cleanliness. Remember to change these oils more frequently than regular motor oils.