JohnnyCat23

Cats were stolen and can't afford new ones right now. Question is how will this thing run once I put some straight pipe or flex pipe on it to quiet it down. Will I have to do something with the o2 sensors?will it run like ****?

mountainmanjoe

FYI operating a motor vehicle with missing/modified emissions equipment is against federal law, and you could be heavily fined.


That depends. Are they still there?
You will definitely get check engine lights with missing cats.

William Kisselstein

Yeah, no, forget what he said. Only if your state requires a safety or emissions inspection is it an issue. It won't pass without them. Maybe it's technically illegal to run without them but plenty do it and as long as it's quiet odds are highly against anyone looking under it - until it's time for that inspection.

As to how it runs, it depends on if the computer cares about the exhaust after the cats, if there is an O2 sensor after them, then it will cause issues because they won't read in the correct range. If the ECM doesn't care what comes out after the converter, then it will probably run okay as long as you get some kind of pipe on it.

In my state it's illegal to sell a used converter, but you can buy a whole vehicle and swap them out and that's legal. Makes no damn sense. Given even on Rock Auto you're looking at about $600 for a pair for Fed emission and more for Cali emission standard it may actually be a viable option to buy a clunker that has cats on it, take them off, and sell the remainder.

The other option may be to look for some universal converters and run those. Lots of room down there and a good length of straight pipe before they Y together may let you cobble something up to get you by.

mountainmanjoe

Emissions equipment regulations are mandated Federally. It has nothing to do with your State, or local inspections. If an officer was having a bad day and wanted to enforce it, they could. Or if you came across a Fed worker/agent of some sort, same thing. How strongly it is enforced in your particular jurisdiction, I cannot say. Environmental bullcrap gets tighter every day. If you get fined, you have been warned.

William Kisselstein

Just one example, although catalytic converters were first used on cars in the late 1970s, in my state only 1984 and newer cars must have them to pass an inspection. Further, my state adopted the California requirements some years ago. Previous to that, California had it's own unique emissions control standards.

When I look on Rock Auto, there's a good dozen different converters for these vans, some are Federal standard and some are California standard. .

If this was all federally controlled there would be one standard. But there's not, and there's nobody to police it either. The EPA doesn't have the personnel to go out and police everybody's vehicles. Nobody's being fined because of a clogged PCV valve or a cat with no element inside. Unless they go bragging about it constantly and get the EPA's attention somehow.

mountainmanjoe

It is Federally controlled, and the standard is plainly laid out, black on white, in the Clean Air Act. Commiefornia's requirements and punishments go above and the BEYOND Federal standard.
The bottom line is that removing a CC is illegal everywhere in the USA. Fines are thousands of dollars and possibly an impound ... a lot more than just buying one. And yes, highway patrol do sometimes check.

If you want to play with fire then that's your prerogative. It's not worth it for me. I need my vehicle for my livelihood. The racket alone is enough to draw attention, let alone the smell, and most shops will not touch your exhaust, because they could be on the hook for a 5 digit fine. Besides, the motor was engineered to have a CC there.

deliveryvanman

It should run just fine. The post cat o2 sensors only check the performance of the catalytic converters. The pre-cat o2 sensors are the ones that are used to adjust fuel/air mixures. These may be affected by the increased flow with the cats being gone, but I would imagine that would be minimal.

William Kisselstein

Yeah, they don't have cat converter police to go look under your car and check if one's there. Sorry. And if the thing is connected to the muffler, there's no noise either.

hanky

There are vehicles out there that use rear catalyst info to control fuel systems.

This is one of those times where what you don't know can hurt you.

There is another one, an insurance co can walk right out from any responsibility if you get involved in a mishap with a vehicle that has been altered from it's original certification. There are hungry lawyers that are more than wiling to let you "Buy the farm"

That 5 figure number by the way starts at $10,000 per screw on a simple carb mixture adjustment.
Smart folks learn the law the easy way ,not the hard way through bad experience.

mountainmanjoe

There's no need for cat police because, as I said, highway patrol is more than capable of checking. I've gutted the cats before, and there's definitely more noise.