ScoobyNoobie

Hi guys,

I have a 03 JDM sti with only 45000kms on the clock.

I've only bought it recently but its drinking oil.
Did a compression test and only read 25psi on 1 cylinder, 135 on all others.

So i've gotta pull out the engine an re-build.

I want it as a weekend road car mainly, and for the odd track day.
Max bhp I'll look for is 400bhp pending a possible turbo upgrade someday.
What do i need to do to future proof it for a possible 400bhp?

I have a 3' turbo back decat, uprated clutch and induction kit already.

Are wossner pistons good quality?
Should i replace the crank or rods for 400bhp?
Cylinder head bolts?
Oil pump?
Water pump?

If so for any of the above, what brands should i be looking at?

Thanks guys!

Henrik

iTrader: (5)

afaik the internals on your engine should be well capable of handling 400bhp.

If it was my engine, I'd pull it apart and see what was up with it and replace as necessary with OEM parts (maybe add uprated bearings if you end up pulling the block apart).

ScoobyNoobie

I think it was probably badly tuned before i got it, as it came with dyno charts of 404bhp, but its still running a standard VF37 which is only capable of absolute max 370bhp as far as I know.

Guess is its a melted piston or valve not seating properly any more.
Will take engine out, and pull off the heads which should make it all quite apparent whats failed.

So OEM pistons??

Henrik

iTrader: (5)

yep, they should be good for that power level.

I'm sure Simon (Jolly Green Monster) said he's mapped a couple to 450ish.

Andy Forrest has some info on his site here: http://www.andyforrestperformance.co.uk/58963.html

ScoobyNoobie

Thanks for that.

Good for 420bhp on standard rods!

Given that genuine sti pistons are about 300 each, and a wossner kit with rings is 420 ish, are the wossner ones able for 400?
Or another brand more reasonable than OEM ones.

stedee

iTrader: (4)

its rebuild - bottom end btw

like you say probably melted piston if your compression low , defo check the injectors though when you rebuild, ive heard of ppl rebuilding then exactly the same as happened because of a dodgy injector - ouch

good luck btw

ScoobyNoobie

What way can you check the injectors?
is there a pressure test or something you can do?

Its quite possible over or under fueling caused the problem alright, whether through bad mapping or faulty injectors.

Although, i don't think its under fueled considering how quick it can empty a tank

stedee

iTrader: (4)

you can do it the proper way when you rebuild and send them off cleaning and checking, its about 100 quid for 4 inj.

or i think you can pull em out and then crank it over ( i have done this myself - not on a scooby) i am not suggesting you do this and i will not be held reponsible for anything that may happen. and yes they **** out alot so get a bucket or something.

stedee

iTrader: (4)

wossner should p1ss 400, the stis ones are dear because they are from subaru

ScoobyNoobie

Is it really bottom end if it is that's a scooby thing only.
Crank, big end's and rods are what most would consider bottom end, Piston, head, valves and cams i'd consider Top end.......because in every other engine, they are nearer the top of the engine

Wossner pistons it will probably be then.

Bealescooby

iTrader: (36)

its a flat 4 (pistons move side2side )so all would class as bottom end , because the pistons / crank /rods are all part of the short motor it's classed as bottom end

ScoobyNoobie

Fair enough...but thats only relevant to scoobies an porsche's then isnt it?

What Compression ratio is the standard EJ207 engine in mine? (03 jdm sti)
I see different brands of pistons ranging from 8.0 to 9.1:1 i think.