Engine/heads question
 

OK, think I know where I'm planning to go with my WRX in the long run, will be parts collecting for the next year or so to assemble a long block off the car to be dropped in.

Think I'm going for a 2.35 CDB with forged internals might go Billet crank but unlikely. Will go for a FMIC probably APS with an APS cold air intake. I'll go for one of the MD series turbos, or possibly one of the APS units. Tubular unequal length headers (ceramic coated). 11 or 14mm Head studs etc. Uprated Oil pump and if possible water pump. It's the top of the engine I'm unsure about.

Obviously I have std WRX heads at present and am not sure which way to go as I want to keep the std ecu etc.
My current thinking is to get a set of Newage WRX heads ported and polished with uprated big valves etc, plus a set of fast road Cams.

Other ideas are to fit STi heads from a newage but will this cause issues with the AVCS?

Before anybody says anything yes I will be swapping the gearbox for either a 6 speed or uprated 5 (PPG).

cylinder heads will make a lot of power. sti 5 polished and ported with 14mm head studs. block will need reworked and be very picky about the gaskets. cams need to be picked carefully as well as to agressive can make the car a nightmare to daily drive.

Been getting some advise and hecking prices etc. Think I may go the 2.5 route as only aiming for around 450bhp and want to keep it a daily driver, thinking I'll try to pick up a s/h 2.5 long engine, and strip it myself then make sure the bottom end is fully forged, uprate the valve train and get some Lateral Cams. POssibly getting the heads ported as well then bite the bullet and go Solaris.

OK I've managed to source a 2.2 CDB for a good price so will be either rebuiling this fully forged as a 2.2 or bored to 2.35.
I've also found some heads, a set of Japanese EJ20 STi heads with AVCS, now the question is will these fit the block? I understand I'll need an aftermarket ECU to get the AVCS to work. I'll also be getting a Spec C inlet so I can remove the tumbers from the inlet.

You shouldn't need any head-work or cams to make under 500 bhp. IMHO

You simply need a correct size turbo to squeeze more in !

Aren't the tumblers only present on the WRX ?

dunx

P.S. You could buy an STI engine loom from a breaker, and fit that to yours.

Yes heads will work, but you will need to modify the loom etc to make use of the AVCS. As dunx also pointed out you dont really need to spend on heads and cams at this level.

Ok Reading through this again you seem to have a mixed bag of mods here, and will be spending more than you need to reach the figure.

If you’re shooting for 450 -500 then the mods below will work, and imo 2.35 and head work is overkill.

Parts Engine wise to consider.

EJ257, Rods and pistons upgraded. Or Forged 2Lt or 2.1
450-500 Bhp bolt on turbo.
Injectors
Twin Plate clutch.
FMIC
Fuel pump.
Gearbox.
11mm head studs.
Oil pump
Water pump OE
Induction.
Aftermarket ECU
Oil Cooler.

Alternative consider the cost of changing to the STI model, and introducing bolt on upgrades to achieve up to 450 figure.

So should I stay with my Std V7 WRX heads? I have the chance to pick up a 2.2 for very little cash which is why I'm looking at this option for the block.

If I had a forged 2.2 or 2.35 with the JDM AVCS heads and Solaris/Simtek with the correct std location turbo what kind of power would be safe?

I know there is the whole STi option and I should have bought one before I sent as much on mine! As I've sorted the exhaust, suspension body work, brakes etc. on mine I want to keep it.

500 bhp ?

dunx

P.S. In as much as any "safe" value can be guaranteed.

So should I stay with my Std V7 WRX heads?

If your keeping to your original plans then yes.

If I had a forged 2.2 or 2.35 with the JDM AVCS heads and Solaris/Simtek with the correct std location turbo what kind of power would be safe?

Built With the EJ22CDB they can run in excess of 500 depending on internal build parts. I still think for a daily driver the 2.5 would be a better option Fwiw EJ22T blocks go for around the 1K mark.

Just to check on this, V7 WRX heads will flow 500BHP, so no need to change the heads at all and just swap the block for a forged 2.5 as the easiest upgrade path?

Which STi heads (if any) could I fit if I was to go for the 2.5 and keep my WRX ECU?
Which STi heads would be best assuming I went for Simtek or Solaris?

On here, the V3 STI heads are one of the best, or it could be the cams....
A 2.5 with AVCS would be a nice road car motor, IMHO

dunx

Ok it's jumped 50bhp :) In terms of cost versus gains on your original post, if your shooting for 450 i would be inclined to leave the heads you have alone. If however you want a better set up with a lower cost than worked heads, STI heads are the way to go, this will also see a improvement in spool up etc due to profiles and avcs what ever you aiming for.

I'm thinking 500Bhp capable but running around 450Bhp on the low boost map