If I were to take off my cats and run an off road x pipe would I fail emmisions? If so those of you who have taken off your cats do you just have your car smogged with them on them have them changed out? The car is registered in Nevada if that makes a difference.

 

Um. Yes you would fail, no they're not there just for smog testing. As far as I know all 50 states require cats. If you ever get pulled over and a cop has reason to believe you modified your exhaust he can either do a quick inspection if he actually knows what to look for, or site you for modified exhaust in which case you will probably have to go to a smog referee to go over your exhaust with a fine tooth comb and they can be pretty picky/****zy.

 

You will fail emmissions if they measure them in your area.

If it's visual only, hollow out the cats, cut a semicircle equal to the diameter of the pipe and spot weld them onto the spot where they would be. Looks like you have cats now.

 

I'm not worried about visual inspections, obviously I'd fail one done by anyone who knows anything about cars. So then for those of you who took off the cats what do you do when you have to get your car smogged?

 

What about your post-cat O2 sensors??

 

No smog tests where I am located I'm planning on putting on the MAC Pro Chamber system this winter.

You will need a tune to ignore the o2 sensors - otherwise your CEL will come on.