GTB exhaust setup/diagram

[Neelie]

guys im a bit confused with the exhaust setup on the B4 GTB twin turbos.
has anyone a quick diagram so i can see what the hell i need to order for mine lol
the way i sorta thought it was is attached, but where does the up-pipe come in then and are they also catted? currently the car has a HKS catback system but the midsection is totally shot with holes and rust. i cant seem to find a HKS replacement though...

if someone can scribble this up for me that would be really cool. google is little help, as usual...
thanks a mill in advance

 

[Neelie]

and this is what I *thought* I could get from souhans if that was possible with this car...

 

[scoobycolm]

At a a guess that would work
some imprezas have 2 cats and one or 2 is removed
so i would assume same principle even with 2 turbos
would require a remap anyway I'd say

would be quicker with cats deleted and just swop one in for test
if twin turbos run ok like that

wonder if 2 classic down pipes can be used
catted mid section
rear classic back box slightly lengthened

 

[Neelie]

well after a little bit more digging on nengun it seems only the primary turbo downpipe has a cat. secondary only has a flexi. so id be removing only 1 cat.... and the mid section muffler... if it needed a remap with though I think id need to pass, for financial reasons lol. I was thinking of maybe getting onto souhans about a new midsection as its cheaper than buying id say. and then while im at it and it was cheaper than I though id get em to do 2x new downpipes also and remove that cat in the 1 downpipe too then so give it more breathing space.

and also if it would pass nct with only the 1 mid section cat in it or not, and also if it has more than I lambda etc there's a lot of factors in it so would really love for someone who knows their leggy's to cast some light on this for me

like so; without cat
http://www.nengun.com/syms/front-pipe

 

[CiaranBC5]

Not an expert on these things, but my Legacy had a mongoose on her, knew she wouldn't past test so cut it off got a cat and back box on her. Tried testing.... failed. Got another cat into system.... failed.
Got original downpipe with Subaru cat in it joined to backbox with stainless and low and behold she passes the emissions test.
You imo will be tortured putting on and taking off systems. Talk to Darren in Souhans he will get you over go through options and pricing then upta you what to do after that

 

[davelegacy]

On a B4 it will pass with Centre section providing all sensors working as they should.

Imo financial wise your best replacing downpipes if rotten with good condition o.e.

And something like a hayward and scott centre and backbox.