Manley Platinum Series Piston and Ring Set for Subaru WRX STi 2004+ (EJ257) - 99.55mm Bore 8.5:1

Fits 2004 and newer Subaru WRX STi models equipped with the EJ257 engine.

Manley Platinum Series pistons are engineered for high-output EJ257 builds, providing the structural integrity required for increased boost and high RPM. Forged from domestic 2618 aluminum alloy, these pistons utilize specialized cam and barrel skirt profiles that maximize power while minimizing wear on cylinder walls. This set features a 99.55mm bore (+0.05mm over stock) and a dish design that maintains an 8.5:1 compression ratio, ideal for forced induction applications.

Each piston is manufactured using Manley's unique fixturing process, which allows for skirt turning and ring groove machining in a single operation. This ensures perfect squareness between the ring groove and the skirt, resulting in a superior ring seal and reduced blow-by. The kit includes premium Chrome Moly wrist pins and a high-performance ring set to complete your bottom-end refresh or build.

• Manufacturer Part Number: 612001C-4
• Engine Fitment: Subaru EJ257 (2.5L)
• Bore Size: 99.55mm (+0.05mm)
• Compression Ratio: 8.5:1
• Stroke: Standard (STD)
• Material: 2618 Forged Aluminum Alloy
• Wrist Pins: Premium Chrome Moly included
• Features: Moly coated skirts and precision-machined ring lands