YumYumturbo

Hi all,

I currently have a sti uk 2004 model & it has a Milltek turbo back exhaust with sports cats. I was going to remove the cat on downpipe & centre section along with middle box, will this help improve performance much or should i just leave it the way it is?
Was going to book in for a remap after all removed & add a bigger fuel pump (walbro 255)

thanks

Yum

JohnD

iTrader: (5)

Is it the 3" Spec C system or the smaller STi system?
My 3" had just a cat in the centre section (+silencer), the 'bulge' in the downpipe being a resonator.
Removing the cats will up the power (after re-map) but you'll need to keep the centre section for MOT time?

JohnD

YumYumturbo

hmmm im not 100% sure if its the spec or sti smaller system. it does look 3".

Is the buldge on the downpipe just a resonator? if so i take it that doesnt need removed?

Not bothered about MOT, i will get it passed ok, lol

Where does the up-pipe sit also, always hear of people changing up-pipe but im not sure where that is, lol

adz556

iTrader: (5)

Your up pipe will be fine mate as you have the sti, the wrx's have a 3rd cat in there. Its the pipe that connects your exhaust manifold to your turbo

martin850

iTrader: (51)

I have got a 3" spec C Miltek system with sports cat on my bugeye wrx and with supporting mods I have got 340bhp so I would leave it as is if I was you

YumYumturbo

nice one cheers, i was so confused wondering where there could be an up pipe, lol

YumYumturbo

the car was rr'd at powerstation in 2011 & it made 347bhp, reason i was looking to remove cats & box was incase i decide to run a 20g turbo which my mate has lying in his garage.

BlueBugEye

iTrader: (12)

If you have the Spec C PowerStation exhaust why remove the cat? I'm at 440 bhp with the cat in mine, a 20g certainly won't be restricted.