I'm seeing some used and also some bargain priced new systems advertised that have no cats. They do a bung for O2 sensors and what looks like a canister without catalyst.

Is there an issue running these. I'd think they may cause a CEL situation, but don't know. If they do is there a way around this? How about a state annual emissions test?

I may want to try one of these to see if I can get a bit more sound, lose some weight back there too. I'm not necessarily into a power gain and understand the potential for drone. With an inexpensive system I may be able to mod the sound with various techniques. If it was not to my liking, I'd just take a bit of a loss and resell it. I can't see spending $3-5K on an exhaust system for an otherwise near stock 15 year old car for a small sound enhancement.

Again, my interest here is potential issues running catless.

TIA!

 

You'd have to get the codes tuned out to do it the right way. Get yourself a COBB, if you don't have a tune you're missing out.

 

I don't know about other states, but in IL if you tune out (disable) the secondary o2 sensor and go for emissions, it will show up disabled in the readiness monitors vs "complete".

You will not get a CEL but ECU will indicate that it is disabled and fail the emissions.

Having said that, some people have had good luck with using o2 sensor spacers while other do not.

I know few people running catless using these successfully and not get a CEL:

 

Thanks ...82x.

The kind of info I'm looking for. I remember from years ago the sensor spacers may work. I guess I'm looking for absolute info that probably is not available on this forum.

I don't know that a catless exhaust is that important right now if potential emissions failure are possible.

Too bad the TT's can never sound as good as the 996 C2 with the PSE.