EJ257 Platinum Series Piston Set with Rings - 99.75 mm Bore, 9.8:1 Compression

• 2004–2014 Subaru | WRX STI
• 2006–2014 Subaru | WRX

Manley's signature Platinum Series pistons deliver forged strength for Subaru EJ257 2.5L turbo engines — 2006-2014 WRX and 2004-2012 WRX STI. Machined from high-strength 2618 alloy forgings with an offset wrist-pin design for quiet start-ups, these 99.75mm (+0.25mm overbore) dished pistons run the stock 79mm stroke with 9.8:1 compression for high-horsepower, high-boost builds. Every kit includes moly-coated skirts, premium chrome moly wrist pins, round wire locks, and premium steel top rings with Napier second rings and higher-tension oil rings from Total Seal.

• Part number: 612102C-4 — set of 4 pistons, wrist pins, ring sets, and round wire locks
• Bore 99.75mm (+0.25mm overbore); -10cc dish; 51cc cylinder head; 9.8:1 compression
• Stock 79mm stroke, 5.137" rod length, 1.209" compression distance; 423 grams each
• Machined from high-strength 2618 alloy forgings with cam and barrel skirt profiles
• Moly-coated skirts and pressure balance groove reduce friction and improve ring seal
• Includes Total Seal ring set 46997DT-4, premium chrome moly wrist pins, and round wire locks
• Accommodates +1mm valve sizes; recommended piston-to-wall clearance .003" (mild boost) / .0035" (high boost)
• Professional installation required — cylinders must be bored and honed to 99.75mm

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