JE Pistons Forged Piston Set for Subaru EJ257 - 99.5mm Bore, 9.5:1 CR (Set of 4) #310936

Fits Subaru EJ257 engines found in WRX STI models requiring a standard 99.5mm bore.

Engineered for high-output racing applications, this JE Pistons forged piston set is manufactured from 2618 T6 high-tensile aluminum to withstand the extreme cylinder pressures of forced induction. Utilizing a proprietary Forged Side Relief (FSR) design, these pistons feature a reduced skirt width and shorter wrist pins to minimize friction and reciprocating weight without compromising structural integrity. The 9.5:1 compression ratio provides an optimized thermal efficiency for tuned EJ-series builds.

To ensure maximum ring life and power consistency, these pistons include an accumulator groove to manage combustion gas pressure and reduce ring flutter. The skirts are finished with a specialized coating to minimize wear on the cylinder walls and reduce operating noise during cold starts.

• Material: 2618 forged aluminum for superior tensile strength
• Bore Size: 99.50mm
• Compression Ratio: 9.5:1
• Design: Forged Side Relief (FSR) for reduced friction and weight
• Features: Integrated accumulator groove and skirt coating
• Included: Set of 4 pistons, high-quality wrist pins, wire locks, and JE Pro Seal premium rings
• Manufacturer Part Number: 310936
• Origin: 100% Engineered, forged, and machined in the USA