[zx9rmal]

So, I really like the sound quality of the OEM exhaust with the fuse pull. But, I wouldn't mind more of it. Not a lot louder, but noticeably louder.

Would cat removal get me that? If so, which ones to remove?

Thanks.

[ST1LE]

Yup, delete the secondary cats. Will give you more sound, and no tune required unless you remove the primary cats.

Edit: https://www.camaro6.com/forums/showthread.php?t=448375

[zx9rmal]

From reading the links, I’m just concerned that the sound will change, which I do it want. Anyone have a sound clip of a ZL1 or SS with secondary cat delete?

[Z OH 6]

The sound will most certainly change, deleting the secondary cats is about as far as you want to go before it gets REALLY loud.

[ST1LE]

and

[esm]

Do it! Not too loud and with the valves closed, it sounds like it did stock. I ended up with a Borla X-pipe before they stopped making them. Love the sound. I ended up having to add spacers for the O2 sensors as I kept getting a CEL.

[zx9rmal]

A CEL from deleting the secondary cats????? That would be a deal breaker for me even though it can be resolved.

Also, is there a slight performance benefit with the delete?

[esm]

Originally Posted by zx9rmal

A CEL from deleting the secondary cats????? That would be a deal breaker for me even though it can be resolved.

Also, is there a slight performance benefit with the delete?

I solved it with the O2 spacers, no big deal and an easy fix. Can't tell if I gained any horsepower, but it sure is worth it for the sound! I also track my car and I will not be tuning it so I can keep my warranty, I understand your concerns.

[zx9rmal]

Originally Posted by esm

I solved it with the O2 spacers, no big deal and an easy fix. Can't tell if I gained any horsepower, but it sure is worth it for the sound! I also track my car and I will not be tuning it so I can keep my warranty, I understand your concerns.

Just so I’m clear, I WILL get a CEL from just doing the secondary cat delete? I thought I read that you don’t, if only deleting the secondaries.

[esm]

Originally Posted by zx9rmal

Just so I’m clear, I WILL get a CEL from just doing the secondary cat delete? I thought I read that you don’t, if only deleting the secondaries.

I can't speak for anyone else, but for my car I got a CEL that said something about Catalyst blahblahblah. I cleared the code and installed the O2 spacers and it has not come back.

[tomster]

YOU SHOULD NOT get a cel deleting the secondary cats. If you do there is an air leak near the downstream o2 sensor. I deleted them on my 18 ZLE and now on my CTS-V no problems only very slight gains in sound. (they are not that restrictive.

If you want more sound the fronts got to go. That will cause a CEL though

[zx9rmal]

Thanks for the info guys. I had the delete done this morning. VERY pleased. The sound, to me, is the same, but a bit louder. I know it's subjective, but throttle response seems a bit better as well.

[zx9rmal]

On another note, someone who works at a well known, quality engine builder/tuner shop asked me how I was driving my car without a tune for the CAI and the cat delete. That it would run like crap. WHAAAAT!?

[Z OH 6]

Originally Posted by zx9rmal

On another note, someone who works at a well known, quality engine builder/tuner shop asked me how I was driving my car without a tune for the CAI and the cat delete. That it would run like crap. WHAAAAT!?

Maybe the shop misunderstood and thought you meant you deleted the primary cats.