Newer engines equipped with performance-enhancing technologies like direct fuel injection and turbochargers, generate increased heat more often then older models. If you’ve owned a vehicle that used oil at irregular intervals you might have experienced “boil off” or volatility. At elevated temperatures during severe service especially in the summer months, oils lighter molecules can boil off or “volatilize”. Engines with direct fuel injection or turbochargers also generate more heat. When this happens oil thickens and viscosity will increase causing the engine to work harder. Amsoil beats the competitors in in boil off. Amsoil signature series beats Mobil 1 by 38% and Royal Purple by 17% in the NOACK Volatility Test. Read More about engine volatility here.