ZRP Forged Pistons for Subaru 2.0L EJ20 WRX-STi crankshaft. 79.0 mm, 92.00 mm diameter, 8.5:1 compression ratio.

Subaru EJ20 / EJ205 pistons are developed for moderate to high-level preparation, mainly for street or club racing cars that want to develop their engine for high mileage and/or street use. Designed by ZRP engineers and manufactured in Germany from high-silicon, low-expansion 4032 (T6) alloy. This allows the engine builder to use a smaller piston-to-cylinder clearance, resulting in a better seal. This minimizes cold start knocking noise, common in engines using forged pistons, providing quiet operation and low oil consumption. We have chosen a full round skirt design with a bottom reinforcement band, with oversized and deeper valve pockets to allow the use of high lift camshaft profiles. They have offset pins for quiet operation and the piston pins are made from 9310 alloy. Other features include anti-detonation grooves to protect the top rings, a gas pressure accumulator groove for better ring sealing and vibration relief. Includes a premium Japanese quality 1.00mm x 1.20mm x 2.80mm ring pack. *Note: Pistons are designed for use in all engine configurations with a 21.00mm pin and 95.20mm long stroke crankshaft. Product Features and Design Anti-detonation grooves for extended life and performance Gas pressure accumulator groove on the second ring for extended life. Horizontal grooves on the pin bore designed to allow oil between the piston pin and the pin bore area. CNC precision machined ring grooves 4032-T6 high silicon/low expansion alloy Pin bores polished Clip cuts on the intake side edge Full round skirt design with bottom reinforcement band for high horsepower/supercharged applications Valve pockets designed to allow oversized valves and high lift camshafts Pistons designed to optimize compression for increased engine life and greater power potential Optional coatings offered on request "Blast Off Bronze" thermal barrier coating "Stealth Black" molybdenum side skirt and under crown coating