Factory vs v4 sti heads

[Dvnt]

Ok so i managed to get my hands on a bg5a wagon and im currently rebuilding a replacement motor for it. It has been converted from twin to single turbo running a vf30 and from what im told v4 sti heads.

What i would like to know is if im just using this as a day to day car and not planning on racing it etc is there any real benefits of putting the v4 heads back on vs the original heads?? just seems like a waste really

[funkytown]

what revision BG wagon is it...

[Dvnt]

 funkytown said:

what revision BG wagon is it...

bg5a

[rex-leggy]

there much better than factory heads.

bg5a ones have hydraulic lifters which can get noisy . also the cam profile in the v4 heads may match the tune a bit better depending on what ecu your running.

[Dvnt]

 rex-leggy said:

there much better than factory heads.

bg5a ones have hydraulic lifters which can get noisy . also the cam profile in the v4 heads may match the tune a bit better depending on what ecu your running.

the factory heads im thinking of putting back on would be out of bd5a legacy, and currently running 1s ecu

[rex-leggy]

I wouldnt put them back on . the reason funky asked was bg5b and ç run good heads from factory but revision a are rubbish really

[funkytown]

But op will have big manifold pattern issues..?

[Guest]

 funkytown said:

But op will have big manifold pattern issues..?

BD/BG is all P1 isnt it? BE/BH P2

[rex-leggy]

yea no issues at all

[funkytown]

isnt v1/2 different to v3/4? and BG5a are the same as v1/2?

i really dont know old legacy stuff - just asking the dumb questions in case OP gets caught out//

[rex-leggy]

 funkytown said:

isnt v1/2 different to v3/4? and BG5a are the same as v1/2?

i really dont know old legacy stuff - just asking the dumb questions in case OP gets caught out//

nope v1 to v4 share the same inline pattern. bg5s are basically the same as v3/v4 but have smaller runners compared to the sti (I know bg5a ones are smaller)

[funkytown]

Derp.. im thinking fuel rails ..;D

[Koom]

 rex-leggy said:

I wouldnt put them back on . the reason funky asked was bg5b and ç run good heads from factory but revision a are rubbish really

This. I\'d throw any Subaru heads with hydraulic lifters off a bridge.

[Dvnt]

lol thanks for that guys will hold onto the v4 heads and scrap the others ;D

[kamineko]

 rex-leggy']

[quote name='funkytown said:

isnt v1/2 different to v3/4? and BG5a are the same as v1/2?

i really dont know old legacy stuff - just asking the dumb questions in case OP gets caught out//

/quote]

nope v1 to v4 share the same inline pattern. bg5s are basically the same as v3/v4 but have smaller runners compared to the sti (I know bg5a ones are smaller)

interesting discussion. bg5a EJ20H definitely has a smaller throttlebody compared to bg5b, v3/4, v2 sti (comparable as all phase1) i didn\'t realise bg5a also had thinner intake runners.

i\'d be surprised if bg5b EJ20R(yellow injector/orange afm) intake runners differed from the v3/v4 spec?

i\'ve singled my bg5b EJ20R with a TD05H / 6S / EBC @ ~18psi / v3 intake / cat converter and i find it super boring until +4Krpm and by-that-time-speeding

i miss my 8.5:1 engine

maybe you\'ll have better luck with the quicker spooling vf30. maybe my compression is poor, i should check that..

[edit, may have derped about teh v2]

[Dvnt]

what happened to your old motor Nic? was that the ra one thats in you retina...

i have yet to see the goods from my vf30 it was only pushing 8-10psi i hope ill see more after rebuilding it