ZRP Std Valves Intake Black Nitride for Audi VW Volkswagen 4.2L R8 32V 8V FSI

Audi / VW 4.2L R8 32V FSI – ZRP Standard Intake Black Nitrided Valves (Set of 16)

ZRP Standard Intake Black Nitrided Valves are engineered for high-performance Audi and VW 4.2L V8 FSI engines, delivering excellent durability, precise valve control, and reliable operation under demanding conditions. Manufactured from one-piece forged high-grade stainless steel, these valves are treated with a specialized black nitriding process to significantly enhance surface hardness and wear resistance.

The black nitriding treatment diffuses nitrogen into the outer layer of the valve, increasing fatigue strength while reducing friction between the valve stem and guide due to the smoother surface finish. Unlike localized chrome coatings, the entire valve—including the stem and head—receives the nitrided layer, ensuring uniform protection and long service life.

Each valve is precision forged, CNC-machined, polished, and tip-hardened to meet strict dimensional tolerances. This results in consistent sealing, stable operation at high RPM, and excellent compatibility with both naturally aspirated and forced-induction engines.

Technical Features

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

• Surface Hardness: Black nitrided layer with hardness up to approx. 800 HV

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

• Treatment Coverage: Full valve nitriding (stem and head)

• Dimensional Accuracy: Tight tolerances for stem concentricity, straightness, and sealing surfaces

Advantages

• Reduced stem-to-guide friction for lower wear and improved high-RPM stability

• Longer service life compared to untreated stainless-steel valves

• Reliable sealing in both naturally aspirated and turbocharged engines

• Suitable for high-performance street and motorsport applications

Additional Information

• Set Quantity: 16 valves

• Material: Black Nitride

• Valve Size: 33.85 mm head / 5.98 mm stem / 104.00 mm length

• Engine Codes: BNS, BYH, BUJ, CAUA

• Application: Audi / VW 4.2L V8 32V FSI (R8 / RS4 Gen.1)