Secondary catalytic converter delete?

Had my secondary cats stolen off my truck a cpl days ago and looking for people who've deleted them out of the system and their experience. Insurance will cover it but looking into just welding test tubes in and using the money on an exhaust. All my research shows that it shouldn't cause a CEL? But will it affect performance or have any negative affects? Any experience or anything with secondary cat delete is welcome. Truck is a 2015 4.0 in Kansas so no emissions testing

 

Where do you live is the first question as it will affect emissions...

 

No emissions testing here... I'm in Kansas sorry should've mentioned that

 

You will have no issues. I have had a URD Y pipe on for several years (in VA with emissions testing) and had no issues. No CEL, no O2 simulator needed. If anything, you should have better flowing exhaust.

 

Rear cats arent monitored by the ECU, you can cut them out "for off road use only"

 

The secondary cat does not effect emissions. There isnt anything after it. There are O2 sensors before and after the first cats. But not on the 2nd

 

Well... they effect emissions at the tail pipe. But again they are not monitored so a CEL wont be thrown if they are not present.

 

Thanks for the response. Any decrease in low end torque or power? Have a noticable difference with my exhaust cut off behind the sensors like it is now

 

I dont know about that.. I have a few power mods, so I cant comment. It will most likely be louder

Ive got 3* cam gears, 4.56 regear, and URD Y pipe and MK3 exhaust, and 33s

 

I’m curious what it sounds like bypassing the muffler. And then with only 2 cats and 1 muffler.

is there any difference between 4 and 2 cats regarding sound?

 

Assuming the thieves didn't cause any collateral damage and cut into the O2 sensor wires or neighboring hoses, deleting the secondary cats shouldn't cause a CEL and should have any noticeable effect on performance. If you weld in test pipes, you may get rasp or burbles which are either annoying AF or a safety feature depending on how shitty the drivers are in your area.

 

Didn't cause any other damage but cut right next to one of the sensors so trying a clamp on isn't an option. Has a lot of rasp with no exhaust but imagine that would be knocked down considerably by the test pipes and exhaust system but don't have much experience with exhaust and none with these engines

 

Mine have been for a long time now without any issues!

 

Does the exhaust fume smell more gasoliney if you do this? I ride motorcycles which were generally catless until very recently so I know the smell, and you tend to forget that cars used to stink if you left them running for too long in an area without a breeze.

 

I think you just answered your own question there pal

 

With no exhaust at all I haven't noticed any fumes... Still have 2 cats in there

 

Replace the cat (s) as why alter it with really unknown results.
No one that responded I believe ever ran a smog test/mixture test to see if it leaned out/enriched the mixture and what the longer-term results to the engine would be.
Back pressure can affect the upstream cat performance. Leaning out runs hotter and can affect the head gaskets. Sure a google can find lots of info on this.
Opening up the exhaust system does not necessarily get you better mileage or performance. Louder/droning is not better to me unless major performance gains.
Hope someone has run documented tests and can post actual results for you to make your decision.

 

I totally get where you're coming from and I would never remove them on my own as that's how the system is designed. I also can't have this happen again if there's no cats on the truck they can get. I'm not really looking for any extra performance necessarily don't wanna lose any through possible things like you mentioned. I've talked to several experienced mechanic friends of mine and asked this question in multiple places and haven't heard any negatives. Also plan on getting a tune put on the truck anyways and that would solve most of those possible issues if not all.