After recently reading a couple of threads on I-club, it seems that the Rigoli cars do use completely std wrx manifolds. He said that any modifying they did to the manifolds lost them power, so even on their 10sec cars, they are totally standard.
Most articles I have read, they all seem to say that the heads too are un-modified.
They only use their custom 2.5" up-pipe, but obviously this is to suit their big turbos too.
I did modify my heads and manifolds, and didnt notice any difference. I also made an up pipe, and matched it to the turbo, but still havent really noticed any gains, as it is still a little laggy ( TD05 ). Hopefully when I eventually do the front entry mod, things will get better.
Has anyone actually done any testing on modified heads/ ported manifolds, to see if it is really worth it.
My car was off the road for some time while I done all those things, so cant really tell if Ive lost any performance, but Im pretty sure I didnt gain much, if any.

 

I noticed slightly quicker spool up after porting OE headers, and a slight increase in boost (with Dawes).

Changing to 4-1 manifold increased spool considerably, but it flows much more at high revs.

Having said that, I'm going back to OE manifold soon for a sanity check

Richard

 

Dowser,

Will be interested to hear the results of the check.
How high up the rev range does the manifold affect the turbo ?
About 4,000revs before the turbo kicks in or does the Dawes compensate ?

Do you notice a lot of lag ?

 

I ported the manifold with stock td04 - then swapped to vf23, threshold moved to 3k3-4. Added the manifold which shifted it another 200rpm higher.

I don't know what effect the 4-1 manifold would have with a td04, never tried it....and wont until the 23 goes bang

Richard

 

4-1 manifold with TD04 spools up (rather suddenly!) at about 2,900. Zero & then bang (the good type ).

 

Stevie,

when I had my manifolds ported - gasflow definately improved - I need to add 1-2% more fuel as the car went lean - implies more efficiency and more power

Trout

 

I am going to do mine, or rather David Wallis is for me

 

David did you only port the manifolds or the heads to ???

/Jan

 

Got a machine shop to port my headers and up-pipe as there was so much metal to remove. There was a very definate improvement in acceleration and the digital boost guage was reading 2psi more.
Have just taken these headers off and was very pleased to see how closely the ports matched.