Carrillo SC7422-1 Forged Piston with Rings for Subaru EJ257 WRX STI

The Carrillo SC7422-1 is a high-performance forged aluminum piston designed specifically for Subaru EJ257 engines found in WRX STI models. This single piston features a 99.75mm (3.927-inch) bore diameter with an 8.2:1 compression ratio, making it ideal for turbocharged and forced induction applications.

Key Specifications:

• Bore: 99.75mm (3.927 inches) - 0.25mm oversize
• Compression Height: 1.208 inches (30.68mm)
• Compression Ratio: 8.2:1
• Stroke: 79mm
• Rod Length: 130.5mm (5.137 inches)
• Wrist Pin Diameter: 0.905 inches (23mm)
• Piston Weight: 399 grams
• Piston Head Volume: +21cc dish with four valve reliefs

Complete Kit Includes:

• One forged aluminum piston
• Piston ring set (1.2mm steel top ring, 1.2mm cast iron second ring, 2.0mm oil ring)
• Wrist pin and retainers

Features and Benefits:

• Fully CNC-machined and balanced to within ±1 gram for precision performance
• Deep valve reliefs accommodate high-lift camshafts and oversized valves
• Custom skirt cam and barrel design with accumulator grooves
• Press-fit or floating wrist pin configuration
• Suitable for turbo, supercharger, and nitrous applications
• Lower compression ratio optimized for high boost levels

CP-Carrillo pistons are manufactured in Irvine, California using state-of-the-art 5-axis CNC machining and advanced computer modeling. Each piston undergoes rigorous quality control inspection to ensure superior performance and reliability in high-performance engine builds. The SC7422-1 requires cylinder boring to achieve proper clearances and ring gap filing for your specific application.