l70byb.

iTrader: (5)

In the process of collecting bits for a 2.1 closed deck build and was wondering Will the version 5/6 sti heads fit the inlet foot print of my blob eye wrx? Don't really want to go down the route of avcs if I can help it . Was thinking of up grading the valve train cams etc of the heads if needed also . Wanting around 500 bhp

kenc

iTrader: (6)

Yep manifold will bolt on.

kiranbaloo

iTrader: (9)

Sti5-6 heads will do 500hp in std form ran mine at 520 .

l70byb.

iTrader: (5)

Perfect!! thanks lads !!

kenc

iTrader: (6)

I would upgrade the valves and springs at a minimum for extra safety..

What ecu are you going to run??, i am at a stage now where i regret sticking with v5/6 heads and not going with AVCS heads,
Rather than fooking around with cams in the v5 v6 heads , A Good STI AVCS heads with standard cams would have seen me a big gain in power.
I got the Syvecs after i had engine in and it was unplanned, but if i had of known i was going with an ecu capable of running avcs i would have built engine with AVCS heads.

Food for thought maybe

l70byb.

iTrader: (5)

Cheers ill keep it in mind

jura11

iTrader: (7)

As above good AVCS heads will help in many aspects,is pain to wire up,but with good ECU is easy to do

We are running too AVCS via Syvecs and on the next engine 2.35L we will be using too AVCS(now JDM Big port heads)


Jura

l70byb.

iTrader: (5)

Ok so if I could get my hands on a set of twin scroll avcs heads will they work on a single scroll setup? Or do I just get single scroll versions ? Also could I run them to start with without wiring up ? So they weren't adjusting? If you know what I mean !!!

kenc

iTrader: (6)

No difference in the heads, its all in the manifold.
If i was you i wouldnt even think of running without it working..
Either plan into your budget to have everything working, so plan for an ecu that can run the Avcs, The old Simtecs can even do it with an ad on, so its not going to be a big spend, as at 500-550 you will need a good ecu anyway.
If you cant fit the avcs/ ecu into your plan and cant have the avcs working, then just stick with your original plan of v5/v6.

But it would be worth the wait and extra few quid to go AVCS, as you will nearly pay the same for the v5/6 heads to start off with.. so its really only running the avcs thats the extra cost/effort

l70byb.

iTrader: (5)

thanks mate just was thinking for running in period but think ill hold out for avcs heads I found a set of spec c twin scroll units for good money so think ill go and buy them tomorrow

kenc

iTrader: (6)

Lucky ******

You are probably aware but just incase, watch out for cracks around valve seats to plug holes

l70byb.

iTrader: (5)

Ok thanks ill check for that!!!

l70byb.

iTrader: (5)

is there any way of telling if these heads are spec c units ? did any other models come with twin scroll ?

Infected by sti

iTrader: (6)

you can run twinscroll setup on uk heads also, im sure the v8 jdm heads are the 'big port heads' and have a different cam profile to the uk sti heads.

V7/8 jdm sti's are all twinscroll models vf37 turbo on jdm sti and vf36 on the spec c models, all v7/8 uk sti are single scroll items vf34/35 iirc

banny sti

iTrader: (68)

Heads have nothing to do with the twin scroll/single scroll turbo setup, as above the JDM heads are big port and have different cam profiles but as Andy F has pointed out previously small port heads are just fine at big power with the correct supporting mods.

sonic93

iTrader: (16)

So I can use avcs heads with my v3 simtec ? I thought it was a big job

banny sti

iTrader: (68)

little more complicated on an sti 3 as the manifold bolt pattern is wrong for the avcs heads but can be done, pretty sure this is what Daz Davies did with his white type but used a newage manifold

Henrik

iTrader: (5)

What's wrong with the standard newage WRX ECU at that power level?

I've got a set of sti6 heads that I'll be using on my new engine, mainly because they can rev 1000rpm more than my WRX heads, and I'll need all the revs I can get with my holset turbo, but I'm not planning on changing the ECU - I don't see the point.

jura11

iTrader: (7)

V7 JDM STi has been non twin scroll,has been only single scroll(VF30 or VF34),both V7 and V8 JDM STi are big port heads


Jura

kenc

iTrader: (6)

I don't actually know how you can 100% identify a pair of spec c heads side by side with jdm sti heads, the inlet on spec c is ment to be one piece but I've also seen inlets up for sale as spec c and they have tumbler deletes so I don't know if its accurate to say spec c is a one piece inlet.
As far as I am aware, the only difference in spec c and normal jdm sti heads is the cam profile..
But I'd love if someone knows different of more to share as going avcs heads is something I am looking at also.

jura11

iTrader: (7)

We are run our JDM AVCS WRX heads with rev limit set up to 7800RPM,which has been enough for MDX321T

About the New age WRX ECU,you will be limited with boost etc.,on UK WRX ECU you can't runand control AVCS if you want to run,on JDM WRX ECU you can run and control AVCS

We are went with S6 and really best our investment has been this ECU


Jura

Henrik

iTrader: (5)

I think the boost limit is due to the map sensor and not the ECU.

For my spec (2.1 with sti6 heads) I see no compelling reason to switch, other than that it'd be nice to have more than one map, and assuming the std ecu can rev to 8k.