Manley Platinum Series 99.5mm STD Bore 9.8:1 Dish Piston Set for 2004-2012 Subaru WRX/STI (EJ257)

Fits select 2004-2012 Subaru Impreza WRX and WRX STI models with the EJ257 engine.

The Manley Platinum Series piston set is engineered for professional engine builders and tuners demanding high-strength components for high-boost EJ257 applications. Forged from domestic 2618 aluminum alloy, these pistons are designed to handle the thermal and mechanical stresses of increased power levels while maintaining a standard 99.5mm bore. This set features a 9.8:1 compression ratio and a dish-style crown, optimized for improved combustion efficiency.

Manley utilizes a specialized manufacturing process where skirt turning and ring groove machining are performed in a single operation. This ensures ultimate squareness between the ring groove and the piston skirt, resulting in a superior ring seal and reduced blow-by. Each piston is finished with a moly skirt coating to minimize friction and prevent scuffing during cold starts and high-load operation.

• Manufacturer Part Number: 612100C-4
• Material: High-strength 2618 forged aluminum alloy
• Bore Size: 99.5mm (Standard Bore)
• Compression Ratio: 9.8:1
• Piston Style: Dish crown
• Wrist Pins: Premium Chrome Moly pins included
• Features: Moly-coated skirts and precision-machined ring lands
• Manufacturing: Single-operation machining for maximum geometric accuracy