SUBARU 2.5L WRX-STi EJ25 / EJ257 (2004-Up) STROKER KITS


  • Diamond Pistons made from 2618 material for High HP/Boost applications
  • • Side gas ports for better ring seal
  • • Tool steel H-13 alloy pins (Rockwell hardness around Rc54)
  • • 3D milling on piston crowns for ready to install finish
  • • Offset pins for quiet operation
  • • Over size and deeper valve pockets
  • • Molly Skirt coating for friction loss and skirt wear protection
  • • Pro-Select Total Seal 1.00mm x 1.20mm x 2.00mm ring set included
  • Heavy Duty Connecting Rods I-Beam Shape for extra rigidity
  • • ARP 2000 rod bolts rated to 220.000psi (3/8″)
  • • AMPCO bushing with radial groove
  • • Dual grooves in thrust face for weight reduction
  • • Shot Peening for improved fatigue life
  • • Multi Stage Heat Treat for maximum strength and dimensional stability
  • • Bend and twist is tightly controlled.
  • • 2 piece forgings from high tensile steel 4340
  • Crankshaft Manufactured from 4340 Precision Billet Steel
  • • Gun drilled crank pin and counterweights to reduce weight and rotating mass.
  • • Dual passage – straight through oil feeding. Each journal having two main sources of oil feed. providing enhanced lubrication at higher RPM.
  • • Nitride process for hardening & Multi-stage Heat Treatment for superior wear resistance
  • • Shot peening for improved fatigue resistance
  • • Micro-polishing for longer bearing life
  • • Journal radium disperse load stress