gazzawrx

iTrader: (11)

Hello all,

basically i'm planning on rebuilding the engine in my 1994 WRX with forged pistons etc, i've got just over £1k to spend on the bits and i'm rebuilding it myself to save on labour costs etc.

What are peoples tried and tested suggestions for forged pistons in the scooby's? I've used JE, Accralite and Wossener in the past on rover turbo engines but i'm not sure what people rate as best for Subaru engines.

Also what boost and bhp can the standrd WRX rods hold before they bend or snap and is it worth getting the STI ones?

After reading on here it seems the acl race shells are the ones to use for the big ends and mains which i'll be getting soon, is there anything else thats worth looking into whilst the engines in bits, obviously trying to keep as close to the budget as possible.

My sums so far are:
£500 pistons
£200 machine work
£150 ACL bearing set
£300 engine gasket set

Is there anything that i'm missing that needs addressing before putting the lump back together?

Also whats the score with the uprated oil pumps and why are the standard Subaru ones not up to the job?

Thank in advance

brendy76

iTrader: (6)

£300 contingency dosh.

prodriverules

iTrader: (52)

Wiseco are a good piston to use mate and on the rods it all depends on what power figure your aiming for,personally id get some h-section steel one's to safe guard yourself.

TonyBurns

iTrader: (3)

Ok, what was wrong with your engine in the first place?

Just depends on what your expecting from the engine really, you pay for what you get.

They are exactly the same rods, no point changing them to the same thing and yes, I would replace the rods, but again, what are your expectations from the engine?

Put it this way, if your going to do the job properly, 1k wont suffice.
As we dont know what has happened to the engine or why your rebuilding, its hard to say what you need.

Tony

gazzawrx

iTrader: (11)

Is there another subaru engine i can buy and fit that will give me the same setup as what i'm planning on building anyway, i know the CDB is the way to go but i haven't got a spare £3-4k for one.

What about the STI lumps are they any stronger than the wrx and what power can they handle comfortably? albeit the mapping's setup right.

Is it possible to use descent uprated parts from different Subaru engines to make one descent engine that'll take a descent amount of power?
TIA

TonyBurns

iTrader: (3)

350-400bhp and similar torque will cost you a gearbox and clutch, then the brakes (2 pots are not very good on a sport let alone a wrx), so thats expense there (a 6 speed box and rear diff is circa 2.5k, or a ppg box new is circa 5k)

You will need new rods if your going over 350bhp (even below 350bhp well mapped cars have thrown a rod just for the hell of it), and I would also look at an uprated oil pump as the classic ones are well known to fail when they get older

Tony

gazzawrx

iTrader: (11)

i should be sorted for a clutch as i believe i have an Exedy one on the way thats good for 400 ish ft/lb torque, the box i'm planning on taking off, inspecting and rebuilding with new bearings etc, without checking the code i think i have the RA box on the car as the acceleration is crazy, are these descent boxes and can they handle 350-400 bhp without too much worry?

gazzawrx

iTrader: (11)

whts the standard piston size on a wrx and whats the maximum oversize bore i can go on an open deck block without risking the cylinder walls being too thin?

What do you think of these pistons, they seem descent enough and i know Mahle to be descent quality, plus they have moly coated skirts which is always a plus point.

http://cgi.ebay.co.uk/SUBARU-FORGED-...item3cb0cc1470

Have the WRX rods got oil squirters on the rods as standard for under piston cooling etc?

gazzawrx

iTrader: (11)

anyone?

rossyboy

iTrader: (8)

nope, not a chance. It'll probably strip itself clean of teeth at the lower end of your target, never mind the top.

See Tony's recommendation on boxes above. You may get an STi 5/6 5 speeder to last for a good while in that range if you are very nice to it, but its a gamble.

gazzawrx

iTrader: (11)

lol fair enough i'll look at the box options Tony suggessted then

gazzawrx

iTrader: (11)

can anyone shed any light on these pistons?

prodriverules

iTrader: (52)

Thoses are very good pistons and the most you can bore is 1mm from 92mm to 93,and WRX open deck hasn't got any under piston squirters mate but the open deck can handle up to about 450/500 bhp.

gazzawrx

iTrader: (11)

ok mate thanks for that, i'll email the company that supply the pistons and see if we can sort a deal out for all the bits i need for a rebuild. Might get a discount if i'm lucky

is an open deck EJ20 engine a centre thrust lump or a rear thrust?