Whether you are looking to refresh tired piston rings on your daily-driver or build a sleeved long block for your next time attack season, YimiSport can help you build a Subaru motor to deliver the results your are seeking. Please call us to discuss your specific application and needs. Below are general guidelines taken from an interview we did with our friends at Import Tuner Magazine.
- 300 whp: No modifications are required to the stock block, assuming all the bolt-on parts and ECU are working in harmony.
- 400 whp: For an EJ205, you should be doing a basic build on the block that would include forged pistons, rods, good bearings, and head studs. Obviously, quality machine work and tight tolerances/quality control are crucial. For an EJ255 and EJ257, all the block needs is a set of forged pistons. 400 whp (particularly on 91 octane pump gas) is when cylinder pressures are high enough that a random knock event can take out the stock pistons. The rest of the internals are more than up to the task.
- 500 whp: We suggest adding forged rods, aftermarket rod and main bearings, and ARP head studs to the EJ25 along with making sure that the oiling system and cooling system are in 100 percent operating order.
- 500+ whp: For over 550 whp, we recommend sleeving the block, as the stock sleeves can become a failure point. For really high-horsepower applications, pinning the mains and oversized head studs and/or an O-ringed cylinder head may become necessary.