Catalytic converters
ok, you are from CA and obviously have good experience in that state. The topic starter wants to buy a post 1974 vehicle and is seeking our advice. So if CA is so incredibly emissions conscious and any modification to the catalytic converter is considered 'tampering', is everything controlled by the service centers that would install the exhaust system? Is it the responsibility of the State or local police to inspect your post 1974 vehicle for a proper carb certified emissions exhaust? I believe NY is following California. Other states are starting to as well. It would be interesting to hear from a New Yawka' or other New England state that has recent experience with regards to a post 1974 passenger car registration and inspection.
Ok, so again, the cut off is not 1974 here. It’s 1975 and older that are exempt. That means the smog laws apply to 1976 and later, 1975 model year vehicles are exempt.
For vehicles that are not exempt you need a smog certificate to register your vehicle in most counties. There are some counties that are totally smog exempt, but that’s a different story. So typically, enforcement usually just consists of not being able to register your vehicle unless it passes smog. Smog certification comes from the smog shops that are inspected and registered and all that. How often you have to smog depends on the year of your vehicle, it’s not every year for all vehicles. New vehicles are exempt for 4 years and if you pay a smog abatement fee you can skip it for 8.
Out of date registration violations fall to local law. There are also some jurisdictions with their own laws, certain cities have passed laws regarding stopping modified vehicles and specifically train their officers on vehicle modifications so they can inspect vehicles and cite them. That was a street racing, tuner kid kind of thing for revenue.
Normally there’s no way for an officer to know you’ve say, removed your catalytic converter and stop you for that. Now, if you straight pipe a new car they’re gonna know, but the stop is gonna be for noise not smog. Once you’re stopped the biggest fine will be for the catalytic converter, but that’s not gonna be why you got stopped. And yeah once you’re stopped you can be checked for all your CARB stickers and things if you’ve replaced OE equipment. Which you can do if the new stuff is CARB. But again, you’d have to be stopped already. And usually an officer isn’t going to check all that stuff unless there’s a really obvious reason to.
All this stuff is readily available on the internet too, feel free to look up anything you have more specific questions on.
Smog Inspections - California DMV