I have a 2009 GTS 2.4L (4b12). I'm dropping a turbo kit in the car sometime next month and my mechanic/tuner recommended I upgrade pistons & rods. I want to get them forged, but I can't find them anywhere. All I'm seeing is 4b11 pistons. Does anyone know where I can find forged pistons for a 2.4L 4b12?

I read on another forum that the 4b11 rods are interchangable with the 4b12. Can anyone clarify this? (it'd make finding rods a lot easier)

 

How much boost will be running to tell you whether you will need new pistons and rods?

 

The tuner said around 15 pounds max if I'm able to get forged internals. Between 6 and 9 if I keep internals stock. The turbo I'm getting is an OEM 09 Ralliart turbo.

 

With forged internals you can go past 15 psi. You can swap Caliber SRT4 pistons and rods.
On stock engine, the reasonable amount of boost is around 7-8 psi.
If you just change the head gasket with a thicker one you can do 11-12 psi.

All depends on your power goal.