DIY: OEM x-pipe secondary cat removal/gut

[gatorfast]

Originally Posted by MikeE92M3

I had my exhaust shop close to me take out the secondary cats and replace it with pipes with a small "crush" at the end so it would fit in the x pipe.

It does NOT drone, and it actually sounds very very good. Has more of a rumble and you can definitely hear its presence under load. I don't feel significant power gains, but it feels more "free."

Just had the same exact thing done to my car. Sounds really aggressive with the oem mod!

[RedNeck_D]

I did this today, Eric thank you for sharing this info!

[beemerboy305]

has anyone got proven gains with doing this ?? is it for sure not gonna cause back pressure by removing that and not just replacing with a straight pipe

[gatorfast]

Originally Posted by beemerboy305

has anyone got proven gains with doing this ?? is it for sure not gonna cause back pressure by removing that and not just replacing with a straight pipe

No gains. This is just for sound.

[s4play]

OP: First awesome write-up!

I plan to do the same thing and wanted to ask you a few things:

a) What rear muffler are you running?

b) IF stock how much increased sound did you get by removing the secondary cats and do you think you gained any power?

c) I'm debating right now to gut the cats or just cut them out since I'm not too worried about the visual part. Would the final effect be the same?

d) If you are running an aftermarket rear muffler, what brand and how's your sound before and after gutting the secondary cats?


Kudos great job, I want to try this before spending $2k+ on a pipe as I prefer to dump that into my Brembo's

[s4play]

Originally Posted by erics02wrx

I have the UUC / Corsa exhaust and I was afraid of the same thing (being to loud) but it was barely noticeable. Its a little louder from the outside of the car but on the inside its maybe 5% louder, if that. I love it!

One more question, have you thought of removing the OEM resonators as well or would that trip the CEL? I guess I'll do one at a time to get the sound I want but wondering if anyone has removed the secondary cats + resonators on a stock X-pipe?

[happos2]

Originally Posted by s4play

OP: First awesome write-up!

I plan to do the same thing and wanted to ask you a few things:

a) What rear muffler are you running?

b) IF stock how much increased sound did you get by removing the secondary cats and do you think you gained any power?

c) I'm debating right now to gut the cats or just cut them out since I'm not too worried about the visual part. Would the final effect be the same?

d) If you are running an aftermarket rear muffler, what brand and how's your sound before and after gutting the secondary cats?


Kudos great job, I want to try this before spending $2k+ on a pipe as I prefer to dump that into my Brembo's

I am not the OP obviously, but the 2ndary cats are essentially HFC (200 cell I think). So removing them, you will gain some power, but probably not that much. I am not sure on sound...

If you don't want to spend $2k+ on a pipe, may I suggest Test Pipes to remove the primary? ~$400 plus some way of removing CEL if that annoys you (couple different ways of doing this with the Tune being the most expensive.)

Just point the thought in your head if you didn't already have it!!

[s4play]

thanks!

I'm getting my work done tomorrow and will report back