ZRP RODS – SUBARU 2.5L EJ25 WRX-STI PISTONS SET

SUBARU EJ25/EJ257 PISTONS ARE DESIGNED FOR MODERATE TO HIGH-PERFORMANCE TUNING, PRIMARILY FOR ROAD RACING OR CLUB RACING CARS LOOKING TO DEVELOP THEIR ENGINES FOR HIGH MILEAGE AND/OR STREET USE. DESIGNED BY ZRP ENGINEERS AND MANUFACTURED IN GERMANY FROM A HIGH-SILICON, LOW-EXPANSION 4032 (T6) ALLOY. THIS ALLOWS THE ENGINE BUILDER TO USE A CLOSER PISTON-TO-BORE CLEARANCE, RESULTING IN BETTER SEALING. THIS MINIMIZES THE SLAPPING NOISE DURING COLD STARTS, COMMON AMONG ENGINES USING FORGED PISTONS, ENSURING QUIET OPERATION AND LOW OIL CONSUMPTION.
WE CHOOSE A FULL-ROUND SKIRT DESIGN WITH A LOWER-REINFORCED 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 WRIST PINS ARE MADE OF 9310 ALLOY. OTHER FEATURES INCLUDE ANTI-KNOCK GROOVES TO PROTECT THE FIRST RINGS, AND A GAS PRESSURE ACCUMULATOR GROOVE FOR IMPROVED RING SEALING AND VIBRATION REDUCTION. A PACK OF PREMIUM JAPANESE-QUALITY 1.00MM X 1.20MM X 2.80MM RINGS IS INCLUDED. PRODUCT FEATURES AND DESIGN ANTI-KNOCK GROOVES FOR LONG LIFE AND HIGH PERFORMANCE GAS PRESSURE ACCUMULATOR GROOVE IN THE SECOND RING FOR INCREASED WEAR RESISTANCE. HORIZONTAL SLOTS IN THE PIN HOLE DESIGNED TO ALLOW OIL TO PENETRATE BETWEEN THE PIN AND THE PIN HOLE AREA. PRECISION CNC MACHINED RING GROOVES HIGH-SILICON/LOW-EXPANSION 4032-T6 ALLOY HONED PIN HOLES SIDE GAS PORTS FOR IMPROVED RING SEALING FULL-ROUND SKIRT WITH LOWER REINFORCEMENT BAND FOR HIGH HP/BOOST VALVE POCKETS DESIGNED TO ALLOW FOR OVERSIZED VALVES AND HIGH-LIFT CAMSHAFTS PISTONS DESIGNED TO OPTIMIZE SQUISH FOR LONGER ENGINE LIFE AND INCREASED POWER POTENTIAL OPTIONAL COATINGS OFFERED UPON REQUEST “BLAST OFF BRONZE” THERMAL BARRIER COATING “STEALTH BLACK” SIDE-SKIRT AND UNDER-CROWN MOLY COATING ADDITIONAL INFORMATION APPLICATION EJ25 / EJ257 WRX-STI (2004-UP) BORE SIZE 100.00MM, 99.50MM , 99.75MM WEIGHT GR. 402, 405, 407 STROKE 79.00MM OFFSET RATIO 8.5:1 OEM OFFSET RATIO 8.0:1 HEIGHT COMP. 30.70MM ACTION 130.45 MM PIN DIAMETER 23.00 MM BRIDGE CLEARANCE -0.35 CCS DOME -19.90CC, -20.30CC, -20.70CC RING SET 21-GNH1000, 21-GNH9950, 21-GNH9975 WRIST PIN PN WP082