Bypassing the Catalytic Converter

Charbel

Member
Location
Lebanon
I own an FX35 2006 which I bought from the USA and shipped to Lebanon. 77K Miles on it.
My catalytic converter is on its way out. Rust has eaten through a big part of the heat shield and they started to rattle when warm.
Instead of replacing them I am thinking of bypassing them by relocating the O2 sensor and replacing the CC with a flex pipe.
In Lebanon our emission laws are not strict and this bypass will not cause an issue with the emission test.
The objective is to save money on parts, increase the performance of the car and make the engine sound better giving the V6 unrestricted access to make more of that V engine music.

I need some recommendations on how best to do it in order not cause the Service Engine Soon to turn on.
 
You can either buy test pipes for $100 (basically just replace the cats with a section of straight pipe and have the O2 bung welded in) or build your own. The result will be the exact same. If you put antifoulers in for the O2 sensors, you should be able to keep the CEL off, these are basically O2 sensor spacers for the rear ones. Keep in mind that if you just straight pipe it, it will be loud and raspy, our V6's do not sound that great. Maybe thing about having resonators welded in to replace the cats. Still get the performance gains since they're straight through, but with a little less noise.
 
Or you can install Magnaflow universal cats. They are $150 each shipped to Lebanon. Test pipes or High Flow cats are very loud IMO
 
You can either buy test pipes for $100 (basically just replace the cats with a section of straight pipe and have the O2 bung welded in) or build your own. The result will be the exact same. If you put antifoulers in for the O2 sensors, you should be able to keep the CEL off, these are basically O2 sensor spacers for the rear ones. Keep in mind that if you just straight pipe it, it will be loud and raspy, our V6's do not sound that great. Maybe thing about having resonators welded in to replace the cats. Still get the performance gains since they're straight through, but with a little less noise.

I will research the antifoulers. Do you know of anybody who did this mod?
So you are saying the resonators will produce a better sound than the straight pipes.
I found this youtube video of an engine with straight pipes and another with resonators
Straight
youtube/watch?v=Q_jk9ROStPE
With resonators
youtube/watch?v=Dmy6J8LUTfw

Sorry but I can't post links yet.
I think you are right. It does sound better with resonators.

Thanks for the help.

---------- Post added at 07:00 PM ---------- Previous post was at 06:41 PM ----------

And this one for 350z with a straight pipe
youtube/watch?v=mqquqg1d7yU

Now the question becomes where should I get a good resonator?
 
Lots of people run test pipes, just do a search. Also on the G35 forums, there are more people there who would have done this. Resonators will produce a better sound since they will help with the rasp. if you've ever heard a VQ without cats, it sounds horrible. It's very buzzy, metallic, etc. I'd recommend getting high flow cats or something if possible. You can get CNT high flow cats for only ~$300 shipped for a set and they're direct bolt on.
 
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