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Subaru WRX EJ205 stroker with Borg Warner EFR7163 turbo dyno graph

Below is a dyno graph and engine and vehicle preparation summary of a 2002 Subaru Impreza WRX wagon we tested recently. Testing was performed with a target boost of 21psi and still a very conservative ECU calibration. Peak boost is 21psi and tapers down to 17psi at redline.

Engine short block build details listed below:

  • OEM EJ205 block (bored 92.5mm, honed with PRE torque plates, deck milled, align honed)
  • New EJ257 heat treated crankshaft; PN: 12200AA330 (rebalanced)
  • King XPG main bearings; PN: MB5382XPG
  • ACL Race connecting rod bearings; PN: 4B8296H
  • Manley forged stroker pistons; PN: 620005C-4 (weight matched as a set and coated skirts and crowns)
  • Manley H-beam forged connecting rods; PN: 14024-4 (weight matched as a set)
  • ARP2000 head studs; PN: 260-4701
  • New OEM STI 11mm oil pump; PN: 15010AA360 (deburred and blueprinted)
  • New OEM gasket kit
  • Gates Racing timing belt kit; PN: TCK328RB
  • New OEM water pump
  • OEM STI baffled oil pan
  • Killer B EJ25 oil strainer

Cylinder head build details listed below:

  • EJ205 cylinder head castings
  • 3 angle valve job
  • deck mill heads
  • measure and adjust valve spring pressures
  • measure and adjust camshaft follower clearance
  • Supertech stainless steel intake and exhaust valves; standard size
  • Supertech dual valve spring kit
  • OEM valve stem seals
  • GSC S1 camshafts

Fuel/Ignition/Misc system:

  • Injector Dynamics ID1000 injectors with PNP harnesses; originally car fitted with FID(Fuel Injector Development) 1000cc injectors; FID injectors made for terrible tip-in, idle, and part throttle driving was horrendous! ID1000 without retune made considerable improvement. After retune, drivability is delightful).
  • Walbro 255 fuel pump
  • New OEM ignition coils
  • New OEM IAC(idle air control) valve
  • Autometer gauge pod replacement bezel
  • Stack oil pressure gauge
  • Stack boost gauge


  • Borla header; already on the car and had to be repaired due to warped header flanges
  • Borla catback exhaust
  • Full Race up-pipe
  • Full Race Borg Warner EFR7163 turbocharger with internal wastegate, recirculating valve, and T25 flange
  • Full Race V-band down pipe
  • Up-pipe, turbine housing, and downpipe ceramic coated by Full Race
  • Mishimoto TMIC kit
  • PRE TGV delete service


  • Spec stage 2 clutch (surprisingly very good feel and street drivability characteristics)
  • 2006 STI 6 speed transmission swap

Finally, the dyno graph! 398WHP using Dynojet calibration! Click to enlarge.

John Allen 02 WRX wagon EFR7163 21psi 06STI trans 3 gear pull