Supertech Mitsubishi 4B11 EVO X Inconel Exhaust Valve - +1mm Oversize - Set of 8

Supertech MEVI-1019-8 – +1 mm Oversize Inconel Exhaust Valve Set (Mitsubishi 4B11 T / Evo X)

Supertech MEVI-1019-8 delivers eight +1 mm oversize exhaust valves crafted from heat-proof Inconel® for the 2.0 L 4B11T engine found in the Mitsubishi Lancer Evolution X and Ralliart. Designed for high-temperature, high-boost use, they outlast OE steel valves while freeing up exhaust flow for greater power potential.

Key Features

• +1 mm head diameter (30 mm) – larger curtain area improves gas evacuation and supports higher horsepower at elevated RPM.

• Inconel 751 nickel-base alloy – retains strength and resists oxidation beyond 900 °C, essential for turbocharged applications.

• One-piece forged construction – eliminates weak weld seams, boosting fatigue resistance during prolonged high boost.

• Single-groove keeper – compatible with most Supertech and OEM retainer/spring packages for straightforward installation.

• Black-nitride stem coating – harder surface (~52 HRC) reduces guide wear and stem friction, enhancing valvetrain stability.

Technical Specifications