sorry to bump an old thread guys but I wanted to hear everyones opinion on this since I don't know.
My car, an N52, has the lower picture from above, meaning I have both primary and secondary cats. I live in Texas, which I'm not even sure is a carb compliant state or not.
Anyways, I was wondering what happens if the secondary or primary cats are removed(pick one, not both).
I read online that removing the first set would yield the biggest gains as they are the most restrictive, but would it cause a CEL to occur or something of that sort? Would I fail the emissions test?
I read that removing the second set would yield little to no gain in power and just slightly increase the noise your car makes, and it also wouldn't produce any CEL or anything. Therefore, its not "worth it" to remove them, unless you want more sound.
I was just curious because I was searching through the forums and found this. I always wondered why my car has two sets of CATS, and if removing one would be beneficial or not.
Edit: Funny that my car has two cats and is considered ULEV-II.. it smells of gasoline when I turn on the car initially >_>
2009 128i Coupe Crimson Red
MODS: -Injen Intake-Magnaflow Exhaust-Carbon Fiber Spoiler - Carbon Fiber Grilles - OZ Ultraleggeras - CF Mirrors