Red Line High Performance Motor Oil and Race Oil may share PAO and ester base stocks, but they are built around very different operating conditions. High Performance Oil uses roughly 1,200–1,300 ppm ZDDP along with a stronger detergent package for engines that see street miles, longer service intervals, and occasional performance use, while Race Oil increases ZDDP to roughly 2,200–2,300 ppm, uses less detergent, and places more emphasis on film strength, friction reduction, and fuel-dilution resistance for engines that are serviced much more frequently. Viscosity selection also differs, with High Performance covering familiar street and performance multigrades and Race Oil offering more specialized competition viscosities. Diesel oil should not be chosen for a gasoline engine simply because it may have higher zinc, since its detergent and dispersant package is designed in part to control the much higher soot load produced by diesel combustion. The real takeaway is that oil should be selected based on the entire application—viscosity, additive package, oil temperature, fuel dilution, service interval, and how the engine is actually used—not one number on the bottle.