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Adding Cats to a Catless system - Any Exhaust Experts here?
Here is a pic of my XS Speed V 3 or 4 on top of my OEM Exhaust. I bought this in late '18 and got a good deal. They had no Catted systems at the time so I got the 'Off Road'.(And I think they no longer produce a system for the C5)
As I get further into my project I'm thinking I'd like to add Cats - for odor reasons only. I don't have emissions check where I live. The X-Pipe is very forward compared to others I've looked at - even XS Speed systems. (I can post pics of others if needed) I test fit the headers and they look very good. The rest of it looks like it'll all line up too. Headers will get sent away for coating.
1- Where is the best pace to weld them in? I understand that the O2 sensors need heat to work correctly? Would adding them behind the X-Pipe work? They would need O2 Bungs wherever I put them. Any suggestions on Make or Model of a Stainless Hi Flow Cat that I should use?
2- There are 5 bungs welded into this system. Circled in red. Why are there 3 in FRONT of the X-Pipe? They are pretty close to the ones in the collector. Why are they there?
Just trying to plan ahead so I don't get too many delays as I move along.
Thanks for any input!!
That pic looks exactly like my ARHeaders. That's where the O2 sensors locate. The extra ones can be used for a Wide Band O2 gauge.
Don't think I've ever seen O2 sensors located after the X pipe
The 2 bungs at the collector are the upstream O2s. The 2 closest to the x pipe are the downstream O2s and the 5th bung is usually to install a wideband sensor for tuning.
My understanding is that universal high flow cats are not going to perform as well as the OEM cats, and would likely not keep P0420/30 codes off. Some cats maybe will but if you are already getting the car tuned after the header install, having the downstream O2s turned off and not bothering with any O2s downstream seems to be what most people do.
I like that thinking. Use the cats for Odor control only but tune them out - Is that what you are suggesting? I know less than a little about performance exhaust. The X-Pipe being so close to the collectors must be a good thing but I would HAVE to put Cats behind it and O2's behind THEM. I am worried they'll run too cool. But just having them is better than smelling like a 60's Muscle Car (Which is fine with me - Maybe not Mrs Shrimp).
Thanks for the replies
I have XSPower headers. The X pipe Y's right off the collector even closer and the cats are after the X. Look them up on Google images to see. I welded the joint in the middle to get rid of the clamps.
You could cut them into the straight part of the pipes between the collector and X and then shorten the pipes after the X the same amount as you added for the cats where they are joined.
I left the rear O2s working for about 7 or 8 years and maybe 60-70k miles before they gave any issue and threw a code so I turned them off. I'd have to check, I might not have actually turned off all the codes and they might still be working marginally. So, those smaller bullet cats do work at least for a while which is to be expected since they are smaller and will deteriorate quicker. I would still recommend you just tune the rears out and turn off the codes since they aren't needed even if you install cats.
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Adding Cats to a Catless system - Any Exhaust Experts here?
