IAG Performance Stage 1 Cylinder Head Package Modified Combustion Chamber 2002-2005 WRX 2.0L S20 Heads
IAG's Stage 1 cylinder heads are intended for those looking for a cost-effective OEM+ replacement. Each package starts with brand new WRX S20 OEM head castings, directly from Subaru of America. The bare castings are visually inspected and then fixtured into our in-house Centroid 5-axis CNC Machine. This is one of the most advanced pieces of precision engine machining equipment in the world.The heads then undergo a cam clearance machining process which removes material from the lifter area where larger lift and duration cam profiles are known to contact the castings. Next, the heads are fixtured in our Serdi 3.0 Valve Guide and Seat Machine to cut all intake and exhaust seats with a multi-angle valve job that suits the flow characteristics of GSC's standard size 36mm Intake and 32mm Exhaust valves. At this point, the heads' decks are resurfaced using our TS-3000 BlockMate, which cuts the aluminum to a smooth, even finish. Next, the heads are ultrasonically cleaned to remove debris and oils from the machining process. Finally, the heads are reassembled using GSC Single Valve Springs and Titanium Retainers along with GSC Viton stem seals.
Stage 1 Head Package Includes:
- (x2) Brand New Subaru OEM S20 WRX Cylinder Head Castings
- (x8) GSC 36mm (Standard) Intake Valves
- (x8) GSC 32mm (Standard) Exhaust Valves
- (x16) GSC Single Valve Springs & Titanium Retainers
- (x16) OEM Valve Guides
- (x16) GSC Valve Stem Seals
- Multi-Angle Valve Job
- Machined Cam Lobe Clearance
- Ultrasonic Cleaning
* Cams / Lifters Sold Separately
In the Centroid, the heads receive combustion chamber modification in which the shapes of the chamber are machined to reduce compression and improve the burn path.