Forged pistons are better than cast in the aftermarket performance world, but why?
Using JE Ultra Series pistons for the example with Jeremy at The Sema Show we dive into how forged pistons hold up better to knock/detonation, can handle more boost pressure/load and heat as well as having greater tensile strength. When it comes to the JE Ultra Series line these forged pistons also have a ceramic coating that helps keep the heat where you want it in the combustion chamber and away from the bottom end of your engine.
JE''s 'perfect skirt coating is also discussed along with how a window is left in the coating which allows machinists to still make accurate measurements when preparing the block. Also discussed is how JE forged pistons also have an aligned grain structure due to their production technique which allows JE to have the grain optimised in high-stress areas of the piston for extra strength (up to 20% but it will depend on the specific piston design).
Not discussed directly but an important aspect of the likes of JE's perfect skirt application is how it not only reduces friction as you would assume but in the case of forged pistons also helps eliminate the piston slap they usually have from cold start as well as false knock.
Lateral and vertical gas ports which allow your piston to seal against the bore are also explained along with the reason pistons have an accumulator groove and of course how the JE Ultra Series pistons come with their Alloy Steel 9310 wrist pins which offer superior tensile strength.
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