ZRP Std Intake Valves Black Nitride for Audi VW Volkswagen 2.7L S4 30V APB Turbo

Audi / VW 2.7L S4 30V APB Turbo – ZRP Standard Intake Black Nitrided Valves (Set of 18)

ZRP Standard Intake Black Nitrided Valves are engineered for the legendary Audi 2.7L 30V APB twin-turbo engine found in the B5 S4. Designed for high-boost and high-RPM applications, these intake valves provide exceptional durability, precise valve control, and long-term reliability for performance street and motorsport builds.

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.

Unlike localized chrome coatings, the entire valve — including both stem and head — receives the black nitrided treatment, ensuring uniform 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 both naturally aspirated and turbocharged 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

• Full black nitriding treatment of stem and head

• Tight tolerances for concentricity, straightness, and sealing surface finish

Advantages

• Reduced stem-to-guide friction

• Longer service life compared to untreated stainless-steel valves

• Reliable sealing in turbocharged applications

• Suitable for high-performance street and motorsport builds

Additional Information

• Set Quantity: 18 valves

• Valve Size: 26.90 mm / 5.96 mm / 105.10 mm

• Application: Audi S4 2.7L 30V Turbo

• Engine Code: APB

• Material: Black Nitride