Albert And Robert Bonamici Of Auto Master AMR
300 whp: The EJ20/EJ25 engines can handle 300 whp maximum with stock internals with no further modifications other than a proper fuel management tune.
400 whp: We suggest a set of forged AMR pistons and billet rods to safely boost up the engine.
500 whp: The same components previously mentioned in the 400-whp package but also include our AMR 9/16-inch "Big Boy" head studs, AMR plate hone, and O-ring the block to increase sealing of the heads to the cylinder block.
500+ whp: Previously mentioned items with the addition of a line-hone to ensure proper bearing clearances, AMR billet crankshaft, and ductile iron sleeves for additional cylinder strength.
Paul Yim And Paul Leung Of Yimi Sport
300 whp: No modifications are required to the stock block, assuming all the bolt-on parts and
ECU tuning 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. for real???
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.