Need advice on Catalytic Converter

I recently got a check engine code P0421 warm up catalyst efficiency below threshold(bank1)
which has to do with catalytic converter according to my mechanic. I first tried pouring a bottle of cataclean
to a full tank of gas to see if this helped clean the cat but unfortunately got code back again.
I have a cobb catted dp for about 7 years now and it has come the time to replace cat so that being said i came across these 3 brands and I'm wondering if any of you have had any experience with these products. GESI cat is out of the equation due to being to expensive , it cost almost like buying a new cobb dp. These 3 below are way cheaper cost wise.
I've been considering 3 products:
https://zzperformance.com/products/catalytic-converters?variant=12623019278447
https://www.burton-racing.com/produ...talytic-converter?_pos=1&_sid=962c8ef7b&_ss=r
https://www.holley.com/products/exhaust/catalytic_converter/49_state/universal/parts/2000130

Can anybody let me know if you have had any previous experience with any of these that can share some light here? all 3 are 200 cell count like the one that came with the DP.
I need to cut out old cat from dp and weld new cat. Thanks in advance for the help.

 

Holley has a good rep in general in the racing world afaik. It's the only brand I recognize I dunno man pick one and send it. We're sure it not just the o2 sensor?

 

Agree I would think o2 sensor before I think cat

 

OP if you do decide to go with an O2 sensor I would recommend the NGK/NTK brand.

Also if you decide to swap the cat I would see if Magnaflow offers anything if you don't want to get the GESI.

I would start with the O2 sensor though as Awa and EB mentioned.

 

Thanks to all of you for kindly sharing your help.
I told my mechanic about the possibility of being oxygen sensor but he told me when its oxygen sensor its a different code and that its mentioning a temp problem of cat not reaching the adecuate heating temp. He told me that when oxygen sensor fails, the codes are different.

P0135: oxygen sensor in front of the catalytic convertor 1, heating circuit / open. P0175: system too rich (bank 2) P0713: fuel trim malfunction (bank 2) P0171: system too lean (bank 1)
trust me i thought the same as you guys but thats the answer i got from him
So thats why im considering the cat.
So brand wise flowmaster?

Thanks. The magnaflow high flow 200 cell cat goes for $735.00, just to much money.

What ngk oxygen sensor model did you purchase?

 

NTK 24393 is primary 02 listed for the Gen2 on Rock Auto which is the one I'm currently running. It looks like the Gen 1 has a different part number for the primary 02.

https://www.rockauto.com/en/catalog...71,exhaust+&+emission,oxygen+(o2)+sensor,5132

 

Gen specific yes.

The rock auto sensors are proving to be very reliable.

And yes, check O2 sensor before replacing the cat.

 

When is the last time you got the car hot and beat on it to "blow the cobwebs out"

 

ooo, yeah, mash that pedal to the floor, might help

 

*not in 5th or 6th gear.

 

I'm having the same issue with the COBB catted downpipe.

First I got a P0421 CEL code, so I tried the O2 extender with no luck (now I have a P0137 CEL code "O2 Sensor Circuit Low Voltage"). I have also replaced the bank 2 O2 sensor twice. Still the same codes with/without the O2 extender.

I've heard that replacing the cat doesn't work, but before going back to stock, hopefully you found a solution with the cat replacement. Any news on this?