Ford 1.6 Ecoboost Supertech Sodium Filled Inconel Exhaust Valve KitMade as a one piece forged valve for higher strength and reliability, Supertech use mostly EV8 (21 4N) for Intake and Exhaust valves but there are other alloys that we use along with different heat treatments to manufacture valves for different applications. Black Nitriding: This is a hardening treatment that even though it is not widely used as the chrome coating, it has several benefits and is becoming very popular, mainly for European and Japanese