Hey folks,

If I chucked on a catback zorst on my 07 STi, knocked out the cats in the stock downpipe, would there be any issues with overboosting/CEL/detonation?

Cheers

Cat back Zorst from what Ive read should be ok but then knocking out the honeycome may well cause issues.

__________________
Arguably my Automobile is Awash with Alliteration - Subaru Sti S202

What kinda issues would we be talking about?

Incorrect backpressure on the exhaust (as the restriction of the catalist, although not a large restriction, has been removed - as well as the catback combined) therefore I'd think a tune would be necessary to help with boost spike etc as you mentioned.

not worth taking a chance on really for the cost of a Verso or ECUtec.

Might as well go Turbo Back and tune and do it properly.

__________________
Arguably my Automobile is Awash with Alliteration - Subaru Sti S202

Yeah, reason I'm asking is cos there are a few days lag between exhaust fitment and tune, just wanna know if it will be okay to drive around till then.

If you haven't knocked out the cats ( which I don't think you have yet ) don't do it and sure as hell don't talk about it on a public forum. Fines are big!!!

Your biggest restriction is the dump pipe design. If you want the sound just do the cat back and enjoy. If you want the performance gain go a full 3in turbo back with a good design dump pipe and high flow cats and get it tuned at the same time.

Be warned though with a good 3in TBE on the standard turbo it MAY spool so well at the track or drags that you can get it to boost cut. I ended up changing turbo's to fix my issue with this as even with the waste gate fully open it would build to much boost.

__________________
Stoner & Webber 2011 World Champions

I'm currently overseas and local laws do not allow aftermarket dump pipes, as such decatting the stock dump pipe is my only option.

I should be getting my ECU tuned a few days after the exhaust is done. As such, I really don't want to waste $ on the tune if the stock cats are going to be restrictive to gains.

So in the interim before I get my ECU tuned, will running around with a catback + decatted dump pipe cause any issues with the engine/turbo?