Engine Rebuild (D.I.Y)
 

hi i have a 96 impreza ej20 and have blown no.1 piston so am planning a rebuild i am looking for advice on what pistons and rods to use. i am having the blocks rebored prob to 92.25 unless anyone can recomend an alternative.
i have an open block.
the car has been well modded and would have been ok but for it overheating causing detonation. i am putting a new rad and thermostat to stop that problem again it already has front mount intercooler and is currently running 343bhp.
obiously i have to rebuild the bottom end pistons , rods bearings ti there anything else required and what sort of pwer gains should i get from this
Thanks in advance

It all depends on what you already have?

will get a list up shortly

im running a td05 turbo, front mount intercooler,walbro fuel pump,550cc injectors,boost controller,full decat,lighten fly wheel,blitz induction kit,link ecu and am getting 343 bhp
will be fitting 92.5mm Wiseco pistons and Eagle rods so hope i will be able to up bhp any ideas what i should be getting ? and any tips (also replacing oil pump and crankshaft bearings )

Speak to David at APi mate.

Power figure referred to above would be right for a 16g turbo with appropriate supporting mods. With a proper forged build you could plump for a larger blower and go for 400+ You'd need to look at your transmission as well though! :)

ive got a different box on and a paddle clutch in already

Cool, have you also upgraded your suspension and brakes? You'd certainly be looking at that if you wanted to venture into the 400 realm! :)

Reckon you will need 6 speed strength if you go any further.

yes its got top and bottom anti roll bars front and back and brembo front caliper with yellow stuff pads
I was under the impresion that the 5 speed box was stronger :confused:

I prefer the ratios on the 5-speed, but unless you have a PPG kit it is certainly not stronger than the 6-speed. Remembering if you go down the 6-speed route you'll need a different rear-diff, prop and probably drive shafts too.

ouch that sounds expensive lol its costing me enough as it is
any thought on which bore to go to 92.5 or 93 ??
and are those pistons and rods ok ?

Id start by saving for a box first. lol

blown piston no.1 and damaged block so thats got to come first lol

if you are planning anything over 350 hp then you are looking at a lot of money to do right. solid, bullet proof, 400hp car costs a pretty penny. 172 is right though. that box of yours will last 5 minutes with 400 hp. 6 speed needed and they are not cheap atm.

guess who's gonna be drivin with his fingers crossed then lol waitin for :shtf:

its not a matter of fingers crossed. learn from people who have already been through the process. you either drive like a granny until you can get the box put in or lunch the five speed and be without your subaru until you either put in a replacement 5 speed or move up to the much stronger 6 speed.

well unfortunately its gonna have to wait as i'm on a tight budget as ive been off sick for 5 months so am pretty much skint

just a quick one i was struggling getting the piston pins (Gudgeon Pins) out even after the circlips had been removed but discovered if you use a extra long 10mm drill bit the type you use to run cables into dual thickness walls and line the engine up just past either TDC or BDC so you can get the drill through the block and past the other con rod through to the back of the piston pin you are trying to remove then hammeer throughit comes out quite easily just ensure you dont go to far past either TDC or BDC that when the pin starts comming out it doesn't hit the threads.
I found this so much easier than other methods i'd tried so thought i would share my finding and hopefully make it easier for others

this is how 90% of people do it

Oh ok just thought i'd stick it up incase anyone was having similar problems as me before trying the above you never know it might save someone pulling thier hair out lol

not two mutually exclusive words. subaru and skint? well they can be but in a nice way. tight budgets and subarus dont tend to mix.

driving her like a granny is going to do yer head in. if yer a youngish lad then then you will be like a dog with two dicks and a belly full of pish. you will want to go fast but you cant for fear of mangling the gearbox. good luck mate. you're gonna need it.

just found out its an STI 5 speed box in it any ideas what sort of power they will handle ?
I know its been good for 343 bhp for the last 3 years so what are its limits ???

Not a lot of difference to what you have