Hi guys my car is a 97 uk turbo2000 wagon and i am going to rebiuld my engine after xmas. If i used standard pistons and rods to build it what is the most bhp that can be got out of them. i want to get to 300 bhp could they handle that?

 

yes

 

300bhp easy.

But are you looking at the originals? Or new ones? And if it's new ones, is there so much difference in buying better? For peace of mind?

 

If buying new, go for updated for piece of mind.

 

Or even peace of mind. Unless you want to give me a piece of your mind.........

 

The rod bolts are the weakest... But you'll be very 'unlucky' if they go all chocolate on you at 300bhp.

 

My bet is forged parts will be cheaper than subaru original parts.

 

was wondering to use original parts and to just buy new rod bolts and big ends and all the other parts and really good gasket set and a clean up

3

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It would be prudent to change the rods for the later 'bolt' type rods instead of keeping the early stud and nut type.
If you fit new studs and nuts to your original rods, they will need resizing before fitting.
The later rods are capable of running 400 so it makes sense to fit them if the build budget will allow it.

Mick

 

Mick

Which Imprezas got the stronger bolts-only solution? Did my STi 5, per chance?! But I'm guessing it was a New Age phase, though?

 

Rods were changed on STi V7 onwards Joz, so yours will prob have the early nut type
(unless Paul changed them).

Mick

 

Mick, I think you're getting muddled up with my previous 93 WRX - it was that car which had STi v.3/4 pistons and Hawk STi rods when it was built. So I'm assuming, by necessity, they were the later bolts? Nice for the subsequent owners then!

Unfortunately, my STi 5 lump is std. with c.50k on it.

 

Ahhh your prob right,was your '93 I was thinking about - mind you I count EJ20's instead of sheep to get to sleep at night

Picture of the 'nut' type rods (top) and bolt type (bottom)





Mick

 

lol I bet you eat/drink/sleep EJ20s.

Yeah, the later bolts are such a more elegant/efficient solution - two fewer points of failure.

 

hi merlin If you fit new studs and nuts to your original rods, they will need resizing before fitting. how do you mean resizing and my original pistons should be ok?. phil

 

Because the studs are a press fit into the rods, there is no guarrantee that the big end on the rod will be absolutley round after the studs are pressed in and the cap torqued up.
If it is out of round,then the rod is re-sized by machining a little off the cap face and rod mating face to make it undersize and then honed back to standard size.

Your pistons should be ok if they measure up ok but a set of STi Version 3~4 HF forged pistons would be better than your Cast pistons.

Mick

 

So how much bhp can the nut type take, and are they really that bad.. also i thought they were forged.