Hypereutectic Flat or Forged Disc?
Moderator
Joined: Jan 2001
Posts: 57,014
Likes: 2,750
From: Virginia
Cast pistons are stock, and can run close tolerances in the engine to reduce noise(knocking sounds when cold).
The Hyper's are something special like Bill said, which makes them stronger than cast, but they can be run close tolerance so they are still fairly quiet.
The forged are what the racers use, are the strongest, but swell up a lot when they get warm, so the tolerance in the block has to be kept large. So they are noisy when first started. They are also very expensive. They are made by taking a hunk of aluminum, and pressing the piston out, which compacts the aluminum, making it stronger.
The Hyper's are something special like Bill said, which makes them stronger than cast, but they can be run close tolerance so they are still fairly quiet.
The forged are what the racers use, are the strongest, but swell up a lot when they get warm, so the tolerance in the block has to be kept large. So they are noisy when first started. They are also very expensive. They are made by taking a hunk of aluminum, and pressing the piston out, which compacts the aluminum, making it stronger.
Cargo Master
Joined: Apr 2003
Posts: 2,408
Likes: 6
From: Parkesburg PA
It was my understanding that many of our trucks (at least 302s) came factory with forged pistons. I know Mustangs up to 92 were forged. Also while searching for pistons for my mustang there are some reasonably priced forged pistons available. Speedpro has a set with rings for like $250.
David
David
