What does anyone know about the strength of the stock pistons under boost? Will stronger rods be sufficient for boost (looking for 300BHP) or would you need new pistons too? I think I recall the rods being the weak point and that the standard pistons would work fine with stronger rods.

for what motor?

SOrry, NA PH I (MY2000) EJ25.

If your replacing one spend the extra little bit of money and both then youll be safe for the long haul.Stock NA pistons and rods are really weak.

If the motor is out just pull off the heads and throw in some new aftermarkst pistons.

Thanks guys. RIght now I am looking at some prices on Eagle or Wiesco postons and rods. Figure I might as well replace them both. ANyone know anything about these?

Of course Ill do a search - but since I am here and asking. :)

Definitely dont take a chance on it. Replace the pistons and rods. You dont want to have to tear the block down twice.

Not sure if they have an application for your motor but you may want to look into Mahle pistons as they come with pistons, rings, wrist pins, ect.. for a very affordable price.

-Matt

k. 00' impreza is a phase II motor just so you know. anyway. I have a 98 impreza with a phase II motor, stock bottom end and run 6psi daily and use 100 shot of nos at the track.(once a week) been running this way for over a year. just my 2 Cents. dont spend them all in one place.

If you're going to do both pistons & rods, just get a stock EJ257 shortblock. It should hold 300BHP all day long and you won't have any type of manufacturing worries.

You'll have to look around to see what type of compression you'll have at that point, though, try the Aftermarket Forced Induction forum FAQ's, or even the Subaru Conversions forum FAQ's. I'm sure the info is posted in one of those two forums.

I've got a set of low compression 9.0~1 forged J&E pistons,high strength wrist pins and locking clips,Hasting rings and crower rods forsale if interested..asking $500, used for 1000mls excellent condition.

this guy knows