Supertech Performance SEVN-1014/2-8 Black Nitrided Exhaust Valves Subaru EJ20 EJ25

These valves feature a +1mm oversized head diameter (33mm) and shortened length design, making them ideal for performance engine builds and racing applications.

Key Features:

• Head diameter: 33.0mm (+1.0mm oversize)
• Stem diameter: 5.96mm
• Length: 104.20mm (-0.5mm shorter than OEM)
• Black nitride coating for superior hardness and reduced friction
• One-piece forged stainless steel construction
• Manufactured from EV8 (21-4N) or EV16 (21-8N) steel alloy
• Heat-treated for optimal strength and durability
• Set includes 8 exhaust valves

Supertech valves undergo specialized heat treatment to achieve the ideal hardness for high-performance applications. The black nitride coating provides a microhardness of 800HV minimum while maintaining excellent ductility beneath the hardened surface layer. This coating creates a smoother surface finish than traditional chrome coatings, resulting in less friction between the valve stem and guide for improved performance and longevity. Perfect for turbocharged, naturally aspirated, and high-compression builds on Subaru WRX, STI, and other EJ-series powered vehicles.