Tuning for an ej20x

[OwenEj20x]

Is anyone able to give me some help understanding tuning for a Subaru? I have an 05 Legacy with an Ej20x, I need to remove my cats because they are clogged and the car is throwing some codes for it. Im thinking ill either cut them and just weld pipe in or ill buy a catless downpipe. Should I be tuning it? If yes, what should I do to get it tuned? Im not looking for power, its my daily driver. The exhaust just isnt flowing properly. Do I take it to someone, and does it need to be dyno'ed then? Or is their a good way to get it etuned.

[KZJonny]

Did you not like the answers you were getting in the other related thread you just started?

Yes. You will almost certainly need a tune for it to run properly. For the other answers you need (catless vs. catted vs. welding in pipes), you’d best talk to a tuner first. Most won’t tune for catless DP’s these days because of emissions laws. A few still will, but you’ll have a hard time finding them. Plenty of places won’t even do JDM engines if they’re not familiar with them.

If you can’t find someone to tune it, then you’re better off spending the money on some high flow cats, and figuring out why your engine clogged the first set in the first place…. They typically last an awfully long time unless they’re being poisoned with coolant or excess unburnt fuel/oil…. Scrap market pricing on cats these days should cover a bunch of that cost anyway.

If you strike out and want to tune it yourself, there is a lot of information in the tuning thread and the hardware is cheap. Not an easy job, but people here have done it.