ZRP Std Intake Valves Black Nitride for Audi VW Volkswagen 3.0L Turbo RS4 RS5 EA839

Audi / VW 3.0L Turbo RS4 / RS5 (EA839) – ZRP Standard Black Nitride Intake Valves (Set of 12)

ZRP Standard Black Nitride Intake Valves are engineered for the Audi RS4 and RS5 EA839 Twin-Turbo engines. Designed for high-performance and high-boost applications, these intake valves provide outstanding durability, dimensional stability, and long-term reliability under demanding thermal and mechanical conditions.

Manufactured from one-piece forged high-grade stainless steel (EV8 / 21-4N), each valve undergoes a specialized black nitriding process. This advanced surface hardening treatment diffuses nitrogen into the outer layer of the valve, significantly increasing wear resistance and fatigue strength while reducing friction between the valve stem and guide due to the smoother, hardened surface.

Unlike localized chrome coatings, the entire valve — including both stem and head — receives the black nitrided treatment, ensuring uniform surface protection and extended service life.

Each valve is precision forged, CNC-machined, polished, and tip hardened to meet strict dimensional tolerances. This guarantees accurate valve seating, stable high-RPM operation, and consistent sealing performance in turbocharged EA839 engines.

Technical Features

• Base Material: High-grade stainless steel (EV8 / 21-4N)

• Surface Hardness: Nitrided layer up to approx. 800 HV

• Manufacturing Process: Precision forged, CNC-machined, polished, and tip hardened

• Treatment Coverage: Full black nitriding of stem and valve head

• Dimensional Accuracy: Tight tolerances for concentricity, straightness, and sealing surface finish

Advantages

• Reduced stem-to-guide friction for lower wear

• Improved high-RPM stability

• Longer service life compared to untreated stainless-steel valves

• Reliable sealing in high-performance turbocharged engines

• Suitable for street, track, and endurance motorsport applications

Additional Information

• Set Quantity: 12 valves

• Valve Size: 33.85 mm / 5.98 mm / 104.00 mm

• Engine: Audi RS4 / RS5 EA839 Twin-Turbo Quattro

• Material: Black Nitride