Just a question to the engine builders out there.

IF I was to do a rebuild on my 94 classic open deck what internals would you put into it and what sort of power gain would you be looking at?

 

I think a limiting factor will be your gearbox. If origonal
If it is a TY752 then you dont want to push things too far.
If you want over 300hp then budget for a replacement TY754 box either at the time of the build or have the money tucked away for when your origonal box lunches itself. Which it might not do...but law of averages dictates it will.

WRX STI or UK spec?
What power figure are you aiming for?

 

I currently have a wrx and have an exact same spare engine but want to uprate internals to be stronger than atandard. My current engine is running 315bhp on standard internals and original gearbox.

 

Of course you wouldn't get any power gain at all from just rebuilding the engine, it'll just enable you to safely derive more power from your choice of turbo, management etc.
You could just rebore and fit a decent set of forged pistons with stock rods and run 350 bhp all day long with the right tuning parts.
Subaru engines most often suffer from poor quality work with a dirty building environment being a major culprit.
If the engineering quality is there, you shouldn't have any bother at all from a well maintained mildly tuned engine.

 

Hi Ian

We are run on the Open Deck Block 490bhp and engine has been build for 500-550bhp

I would suggest 2.1L stroker, which will give you more torque and those extra 100cc will give you better spool up in my view

About the internals,depends on your budget and bhp target,but Mahle pistons with Manley Rods(K1 are not expensive over Manley Rods) should be good for 500-550bhp,11mm ARP headstuds(Cosworth 11mm 260k psi headstuds are used too with good results),ACL bearing set(big and main bearing set),EJ257 crankshaft if you are thing go with 2.1L,I would choose Cosworth Headgasket

As I said depends on the bhp target and after that I would choose the heads etc.

Hope this help



Jura

 

Every bit of info helps. I am not looking at huge power, a nice 350bhp which will run safe without putting loads of stress on the engine. I also don't want to be going through gearbox's so that has to come into it as well.