The ultimate high-temperature protection and recommended for street use. Good for engines that regularly run very high oil temperatures. Best for engines that run large clearances, big displacement, and racing engines that see occasional street use. Popular in air-cooled VW and Porsche applications as well as heavily-boosted turbocharged applications. Provides 25% more viscosity in bearings than petroleum 20W-50s. Not recommended for use in cold climates where temperatures are at or below 10F or -12C. Not recommended for street use in production engines that see sustained oil temperatures below 225F (those engines should use Red Line 10W-30 or 10W-40).