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Subaru high compression forged pistons

We offer a range of TechWorks engineered pistons to match your performance application.  All our pistons feature proprietary high-quench designs that dramatically reduce detonation and create a rapid burn combustion chamber allowing for higher boost levels and higher compression ratios safely. 

This page is under construction.   See Pricing Chart for more pistons.

All Pistons use Ultra-Light Forging

We chose piston manufacturer Wiseco to produce our pistons, and we use their latest ultra light forging for all our proprietary designs.  The new ultra light (374 grams) forging features a strutted crown that provides additional strength for extreme power applications.  Slipper skirts are used for reduced friction at high rpm.  A minimized wrist pin boss spacing virtually eliminates pin flex allowing the use of lighter pins safely.  A reduction of 100 grams can be realized when combined with our light weight hollow piston pins.


STi Turbo

Our exclusive high-quench crown design for the STi:

  • Trench valve relief design
    • Increases low valve lift flow
    • Accommodates STi, WRX, EJ25 SOHC, and  EJ25 DOHC  heads
    • Increases combustion chamber boundary turbulence for less ignition lead and reduced detonation
  • Quench pad area is maximized for all head combinations
    • Dramatically reduces detonation
    • Allows higher boost and higher compression ratios
    • Creates a very rapid burn combustion chamber when combined with correct piston to head clearances


Impreza RS/TS, Legacy, Baja, Forester, SOHC 2.5L

Our asymmetrical crown design mirrors the combustion chamber as closely as possible to maximize the quench area.

  • Compression ratios of  9.0:1 and 11.2:1 (on 91 octane) are available off the shelf.  Turbo and N/A
  • Ultra light weight Wiseco forging
  • Quench pads for reduced detonation allowing higher boost and compression ratios.





Impreza RS, Legacy, Forester, DOHC 2.5L

We offer your choice of forgings for the sometimes 'noisy' DOHC engine.  Choose the long skirt design for reduced piston knock or the slipper skirt design for lower friction at high rpm.

  • Long skirt forging for quieter running.
  • Slipper skirt ultra light forging also available
  • Quench pads for reduced detonation
  • 9.0:1, 11.2:1 (91 octane) available off the shelf Turbo and N/A

2.5L DOHC Racing Pistons

12.5:1 CR pistons available for racing applications and come in a kit with titanium pins, clips, rings, ceramic coated crowns and moly-graphite coated skirts.





















Description SKU # Price (USD)
STi 8.25:1 Pistons 99.5 Call $743.58
STi 8.25:1 Pistons 100mm Call $743.58
EJ20 8:1 <'98 Pistons 92.5mm Call Call
EJ20 8:1 >'98 Pistons 92.5mm Call Call
EJ25 STi w/ WRX Heads Pistons Call Call
EJ20 8.35:1 WRX Pistons 92mm Call Call
EJ20 8.35:1 WRX Piston92.5mm Call Call
EJ20 8.35:1 WRX Pistons 93mm Call Call
EJ25 9:1 SOHC Pistons 99.5mm 25-TC-pis-995 $ 743.68
EJ25 9:1 SOHC Pistons 100mm 25-TC-pis-100 $ 743.68
EJ25 9:1 DOHC Pistons 99.5mm 25-TC-pid-995 $ 743.68
EJ25 9:1 DOHC Pistons 100mm 25-TC-pid-100 $ 743.68
EJ25 11.2:1SOHCPistons 99.5mm 25-HO-pis-995 $ 743.68
EJ25 11.2:1 SOHCPistons100mm 25-HO-pis-100 $ 743.68
Racing DOHC Piston Kit 25-RC-pik-??? Call
Racing DOHC Piston Kit 25-RC-pik-??? Call
Piston Rings 99.5mm 25-SS-pir-995 Call
Piston Rings 100mm 25-SS-pir-100 Call
Light Weight Wrist Pins & Clips 25-RC-pin-000 $ 167.24
Ceramic Coating on Crowns 25-CC-pis-000 $ 190.96
Moly-Graphite Coating on Skirts 25-MG-pis-000 $ 190.96
Billet Steel Connecting Rods 25-RC-rod-000 $ 1141.62
Contact us for more information


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