[EDIT: Title should be "CARB legal cat-back exhaust"]

OK, here are my standard disclaimers: (1) I've done the search thing. (2) I also know that normally, a cat-back exhaust is not subject to smog laws.

However, as far as I can tell, the Evo cat-back exhaust has an O2 sensor and a bung for it, which facts strongly suggest to me that it is part of the "emissions system" subject to the smog laws of the California Air Resources Board.

In other words, at least in California, my impression is that I may not replace the cat-back exhaust system without an executive order (EO) number approving the replacement unit as smog-compliant. (If I'm wrong, please feel free to correct me, but please don't call me an idiot. )

And now, finally, my question: I hear that Greddy Evo cat-back exhausts have EO numbers (at least that's what one of their employees posted on this forum). Are any of the other cat-back exhausts CARB EO certified? Thanks.

 

there is no such thing...once you delete that cat...it's no longer CARB.

 

If you change your stock cat It will not be smog compliant. A TBE usally means you would have a test pipe or a high flow cat after the aftermarket DP or a one piece DP including cat/no cat. Most in cali switch back and forth at inspection time

 

Ok there are no EO number for exhaust systems. Any modification done before the catalytic converter is considered altered emmisions components and those do require an EO number. Cat back exhausts do not have one. As long as the Exhaust meets the 95db the exhaust is fine. Theoretically you can have a turboback that meets the 95db sound but you will not pass smog period. Hi flow cats do nothing for you in california but supress sound.

Here is a link to CARB's aftermarket database
http://www.arb.ca.gov/msprog/aftermk...es/amquery.php
If someone said that the greddy turbo back has an EO number you will find it in here.

 

Thanks. I guess I'm more ignorant than I thought: Do TBEs on the Evos replace the cat or bolt on after the cat? I was assuming they bolted on after the cat, so I should have just referred to them as cat-backs, not turbo backs. But even if they are true cat-backs, it looks like they have an O2 sensor built in.

I need to find some photos on this fourm; I know I've seen plenty of them before around here.

 

it's all the way from your o2 housing back...so pretty much goes like this:

not smog legal: downpipe, hiflo or test pipe.

smog legal: cat back under 95 db.

a tb for the evo is catback, testpipe, downpipe.

 

It depends I'm running the Invidia DP and Cat back with the stock cat. So because of the DP I won't pass smog. If you wanna be quiet get the Fujitsobo Legalis R. That with the downpipe and it will be pretty quiet. And yes cat backs have an O2 sensor bung hole. However that only works if you keep the stock cat. Put a test pipe or catless downpipe and your CEL will come on

 

OK, I think I understand now. Makes sense. Thanks for your patience, all.

What I am talking about then is just a cat-back exhaust, leaving the factory cat and down-pipe in place. It sounds like you guys believe that, even though it has an O2 sensor bung, it's not subject to any smog regulations, and only sound restrictions. Is that true? I always thought that if it had an O2 sensor, it was considered part of the emissions system?

 

The O2 sensor is there to make sure that what is coming from the Cat is clean. The catback is now and emmision device hence you can a huge fart canon and pass smog. It just has to be under 95db to keep it legal audio wise

 

OK; thanks.

 

so if the CEL light comes on, there will be a problem passing emissions? what if you turn off the CEL light. or does it have anything to do emissions?

 

This is why I love NM. You can get rid of the Cat and get a o2 sensor and it will no longer code. Emissions out here the look to see what your car idels at and check to see if it codes, "check engine light" and if not its all good.