QUOTE(JamesM @ Dec 27 2022, 01:35 PM)
Worth mentioning though that forged tend to be lighter.
Let’s be very careful with terminology.
Forged piston material is
denser due to the forging process.
Therefore if the piston geometry is 100% the same between cast and forged, the forged piston will be heavier.
Yes, it is true a performance oriented forged piston may be lighter in some cases (but not always) because they may have shorter piston skirts, thinner piston domes, etc.
Particularly in the case of shorter forged piston skirts, combined with the higher thermal expansion, this makes the cold start piston slap even noisier.
I tried to quicky find the weight of KB Hypers vs JE Forged but came up empty handed searching their online catalogs. If someone is truly wanting a lighter forged piston, be sure to do your homework and contact the vendors directly for tech data.
Lest anyone think I am opposed to forged pistons - I do have a set of 100mm JEs with CNC thinned domes awaiting a special build. As stated previously, forged pistons have their applications but are not mandatory for a mild 2056 street build.