11-10-2003, 03:34 PM
|
 |
BOOOOOOOOOOOOOOOOOST
|
|
Join Date: Feb 2001
Location: Madison, WI
Posts: 2,800
|
|
|
Re: Forged vises Cast.
Quote:
Originally posted by oab_au
Yes the pistons are a pressure casting and the crank and rods are forged steel.
The advantages with forged pistons is there strength at high rpm. The pressure cast pistons are fine for our motor, it is just when the RPMs are up around 7000 to 8000 that forging is best as the cast pistons can crack around the oil ring groove, and at the wrist pin bosses.
I think the WRX uses pressure cast pistons also, it is when the sustained RPMs are higher that forging is needed, as in the WRX 22B Sti. Cost is the factor, forged slugs take a lot of machine finishing as the section is thicker and the wrist pin cutaways have to be machined in, instead of cast in.
Pressure casting is a lot stronger than gravity cast piston, porosity is not a problem in pressure casting.
Harvey.
|
ok harvey, now does shot peened= forging?
phil
__________________
~Phil
Teal 1992 Subaru SVX Turbo - Sold in May 2011 to peace-frog.
|