Hey everyone,

I researched many threads on cats but didn't find a specific discussion on the topic in my title.

Has anyone added (welded in) aftermarket/universal secondary cats to their non-OEM cat back exhaust? If so, what brand and model did you choose?

I'm running a Joe Z exhaust and wondering if this will help make the cat back more "compliant" with a CA visual check.

I have searched for a used OEM cat back exhaust and the prices are absurd. Hence, why I'm considering adding aftermarket/universal secondary cats as a less expensive alternative.

I'm open to any suggestions and insights. Thanks!

- Theo

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I'm running a Borla cat back with GESI cats. I don't know if they're CARB compliant. GESI is the best you can get.

 

I'm running a Borla cat back system with Magnaflow cats... no, its not CARB compliant but they've passed the "visual" inspection during smog.

 

Yes we sell GESI cats for this purpose.

-Josh

 

Lots & Lots of threads one this topic - Here is one I started:

https://www.clublexus.com/forums/is-...w-no-more.html

 

This is really the main purpose. I did find some threads discussing quality and longevity of Magnaflow versus GESI cats but really it's to visually pass even tough smog techs.

I may be reaching out soon regarding this.

Thanks for sharing. I was searching just based on titles and maybe I was searching too specifically.


Thank you all for sharing your thoughts and insights. It's been awhile since I posted and I'm just getting back into the Lexus scene after my wife commandeered our 2019 MDX Sport Hybrid.

 

Are you able to reference the Magnaflow cats' part number that you used? I guess I might possibly need different sizing since I have a Joe Z exhaust though. Thanks.

 

When I got my PPE headers on the car years ago, the MagnaFlow 59905 was what was recommended, but members on here reported the MagnaFlow cats failing so everyone has gone with Gesi cats instead. Distributors will not ship these MagnaFlow cats to CA because they are not carb compliant, so I had to get them shipped to another state where my brother was visiting and he just put then in his suitcase and brought them back.

 

Thanks for the part number. Your story makes sense because yesterday, I did a quick search on Magnaflow cats and it linked to Amazon. It said that based on my address, the item cannot ship to my address.

see, so that's the backstory with Gesi cats. Prior to researching this topic, I had not heard of that brand since I was out of the Lexus game for awhile.