Engine/heads questions/ideas
 

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).

i think a biliet crank would be ott, When i spoke to rcm olly said 14mm head studs is a must over 450, 6 speed would be better a the ppgs are only rated to 450bhp so 6 speed would be future proof.

if you your going for a 2.35 i would deffo want to run avcs heads and a after market ecu somthink with knock control.
if your keeping with the bolt on turbos have you thought about an ej257? i belive zen are doing some liner strenthers, with are ment to be really good.

whats your target?

tone

valvetrain, subaru valve are known for being large, i spoke to pat about valves he said Iv seen 620hp on standard valves. i would look at a set of Supertech one piece valves. as standard valves the heads fall off.

some times cams can be too big and need to be speced for the turbo you plan to be running.

If you have the money go for a solaris and avacs
otherwise v5 sti heads is the way , hence i now have v5 sti heads .
Otherways are newage wrx heads with bigger cams but with polishing and the rest of it it would work out cheaper to go avacs .
When the miss fire is sorted happy to take you for a blast !

Might have to just bite the bullet and go for a 2.5 Cosworth Long block with their heads and cams and simtek or Solaris - was thinking of trying something different and picking as much up as I can on the cheap but looking about the 2.2 blocks are pretty expensive so I guess it's 2.5 or 2 CDB. On the basis it will be a daily(ish) drivern I don't think I'll need much over 450!

2.5 semi is happy at 450
Mine including my turbo has cost just under 4k

EJ257 semi closed
Sti 9 crank
ACL 11mm stud kit
ACL race bearing trust & end
Pauter rods (same as the fasted scoob in europe )
Mahle low silicon forged pistons ( good for over a 1000bhp ( may be one day ))
Sti 5 heads which I ported on the exhaust side & rebuilt
RCM uprated oil pump
1.5mm cosworth head gaskets
Cosworth kevlar cambelt
Cosworth cambelt guide
Cosworth baffle plate
Laterial tubular headers ( fitted to last engine )
MD321 T
800cc injectors

Sounds similar to my original plan but with a 2.35....

Now is it worth going for V5 heads or would my WRX heads with porting and uprated valves and some fast road cams be as good meaning I could stick with my ECU and manifold.

V5 heads are a cheap option and good for 500bhp
different cams can cost £800 on there own new, then there is the valves and associated work to port and your end up spending £1500 to £1800 pound
so you would be better off going avacs and a new ecu

SMG dosnt recommend 14mm til over 550bhp and Andy F still uses the standard classic sti crank in his car

So to go AVACS I may as well get a V8 onwards Sti 2.5 long engine complete then strip and rebuild uprating where needed. E.g Billet Crank, Rods and Pistons, uprated Valves springs etc. where can I get the liners from if I need them? This would give me the Heads, Manifold and block for around 2k For a goodun beofre the rebuild - Saw a Spec C block complete with manifold and twin scroll turbo/headers for £2k the other day. So if I had the funds this would be a good base?

Or get a second hand set of V5 heads with cams etc and just rebuild them onto a 2.5 Block? I'd need a V5 intake manifold as well anything else on a V5 build?

Spec C is a great base for your target and with the twin scroll set up will make a very fast point to point car

Your better of with a seasoned block infact this is a whole bottom end at a very good price with liners http://www.surreyscoobies.co.uk/foru...614#post337614
If you go AVACs get JDM ones as there better , AVACs are bolt on with nothing needing to be done to them
No you would re use you inlet not a v5

A Spec C will out perform a 2.5 everyday at the bhp your target is, id bet money on it

So if I was to go the 2.5 Route I'd be best of getting a 2.5 Sti Long engine so I get a set of AVACS heads and Sti cams. Then rebuild the bottom end to a similar spec to CJ's i.e. Uprated Pistons, Rods and head studs plus bearings gaskets etc.
Then fit this along with a Solaris or Simtek and a MD321 T or V turbo?

Would I then need a new intake manifold to match the AVACS heads and also I guess a tumbler delete solution and larger injectors/parallel fuel rail setup.

Are all the 2.5 Blocks Semi closed.

Ideally I'd like something that could make 500 but run it at 450ish, maybe with switchable maps.

all 2.5's are semi blocks and t or t+ is all a semi will take .
as said above you would be better of with a second hand block and jap spec avacs
Inlet would fit but tumbler delete would be good or a spec c one piece inlet

the price diffrence for the bolts in 11-12-14mm is hardly and diffrence, apart from machaning costs(250ish) for the 12 14 would rather be safe than sorry:nod:

A semi closed is never gonna take the boost so a waste of money

How much boost/what turbo can the SCD blocks take? Should I stick with the 2.0 CDB or reduce my aims?

How much does linering cost and how does it work?

Sorry mate that was aimed at Tone

Im running a fully forged 2.0 semi closed with a md321t at 1.6 bar for 450bhp

I personally wouldnt go over 450 on a semi and is the reason im having a CDB 2.1 made to go further

Liners are close to £1000

1.5 bar is thought as a safe point for 2.5 semi's as they have between a 1.5 to 1.8 mm liner .
If you have the money a closed block is the better option as it wil take a 6mm liner allowing more boost .
saying that i'm having two boost levels one at 1.5 and one a bit more :-D