CNC Subaru Hybrid EJ20 / EJ25 cylinder head combustion chamber program

EJ20/EJ25 Hybrid CNC cylinder head CNC program that keeps the compression ratio and combustion specs of an EJ257 STI head on EJ20 heads. Instead of using custom pistons or thicker head gaskets to lower the compression, our CNC program takes the 2.0 heads and opens the combustion chamber into an EJ257 replica that improves the effectiveness of the quench area, eliminates hot spots and sharp edges, and maintains the compression ratio of a stock STI-this process makes running EJ20 heads on an EJ25 bottom-end easy and effective.
We mapped out the EJ257 STI combustion chamber so it’s exactly replicated on every chamber. This means the ultimate in consistency and the ability to run quality OEM STI head-gaskets and as mentioned, maintain the stock STI compression ratio.
Customers report GREAT results on their hybrid setups in regards to consistent and more aggressive timing curves, better drivability (even in the heat), better fuel economy, and more consistent power thanks to a more efficient combustion.
Experienced tuners have stated they can run over 15-degrees more timing advance under low-load conditions compared to a hybrid build that uses unmodified EJ20 heads and thicker head-gaskets.
CNC program is available for EJ207 and EJ205 heads.
Contact RankinPerformanceMachine
or
[phone]