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Always know the federal and state laws that govern the removal or replacement of a catalytic converter on any vehicle, no matter what you may use the vehicle for. A lot of people will replace the converter with straight pipe or after-market exhaust pipe. According to federal law, catalytic converters may not be removed and replaced with "converter replacement pipes" by any person. The 1990 Clean Air Act Amendments even prohibit private individuals from installing "converter replacement pipes" on their own vehicles. Anyone who installs such pipes would violate the Clean Air Act. Some may think it's okay to remove a converter if they are offroading, but the law still provides you with the guidelines to follow. All manufacturers certify each engine and chassis configuration meet emission standards and cannot be de-certified by anyone for offroad use.
When replacing your converter, always use a reputable muffler or exhaust shop or a dealership to make the proper repairs or replacements. These shop owners and dealership owners will not take a chance of being shut down just to make a quick dollar.
Many older vehicles are not required to have catalytic converters, or much other emissions equipment.
Why does the government not require these older cars to meet current emission standards?
Simply put, they are a dying breed. Most pre-cat cars (pre-78) that do survive today are not daily drivers. Not to mention, the emissions from all of the non-catalyzed vehicles can't hold a candle to a coal burning power plant.
According to the EPA (Environmental Protection Agency), there are laws and rules to follow when replacing your catalytic converter. The rules and laws are strict and should always be followed. And though the laws vary from state to state, the federal guidelines stay the same. Businesses that ignore these guidelines can face fines and/or the loss of its business permits and licenses. The EPA has the ability to shut down the business for non-compliance to these laws, rules and guidelines.
If you take your vehicle to a muffler shop or exhaust shop to get the catalytic converter removed,(without another being installed), by law the shop can't help you or perform the work because no vehicle is allowed on the road without a catalytic converter. If you're already missing the catalytic converter, they still may not help you for fear of losing the business license or being shut down. Most states require an emissions inspection now and a vehicle without a catalytic converter will not pass this inspection. Most federal guidelines state that replacement converters may be installed only in the following situations:
1. A state or local inspection program has determined that the existing converter needs replacement
2. Vehicles manufactured prior to 1996 must have more than 50,000 miles and a legitimate need for replacement must be established and documented
3. In cases of OBD Il-equipped vehicles (1996 and later), the O.E. manufacturer's 8-year/80,000-mile warranty must have expired and a legitimate need for replacement must be established and documented.
(Note that Federal law prohibits removal or replacement of a properly functioning O.E. converter).
Some muffler shops or exhaust shops will replace a perfectly working converter for profit, even thought the law states otherwise. Other laws and guidelines state:
1. It is installed in the same location as the original
2. It is the same type as the original (i.e., two-way, three-way, three-way plus air/three-way plus oxidation)
3. It is the proper model for the vehicle application as determined and specified by the manufacturer
4. It is properly connected to any existing air injection components on the vehicle
5. It is installed with any other required converter for a particular application
6. It is accompanied by a warranty information card to be completed by the installer. These laws and federal guidelines are put into place for a reason.
Catalytic converters on most production cars are not designed for high performance engines. If you start hot rodding your engine and exhaust, don't forget to upgrade your cat too, since this will be a likely bottleneck. Be sure to check your local emission laws, as sometimes it is only legal to replace a catalytic converter if it is defective or broken. This is why many exhaust companies sell "cat-back" exhaust systems, which is basically the full exhaust from the exit of the cats, to the tailpipes. A good high flow catalytic converter will have an inlet and outlet the same size as the rest of the exhaust pipes to give you maximum airflow.
If you own a newer car, and want to start swapping out engine parts, the government has very strict guidelines as to what you change, and how you do it.
Swapping out the factory catalytic converter is usually prohibited, so the best exhaust upgrade is a high flow cat-back exhaust system. This will replace the entire exhaust sytem from the catalytic converter back to the tailpipe.
A well designed cat back system should net you 15 to 50 horsepower, depending on what you're startijng with.
The catalytic converter has no mechanical working parts inside, it is designed to help the flow of harmful gases. There are many reasons a catalytic converter would fail. Sometimes the converter is dented or has a hole in it. Other times, it's a cracked converter neck. Damage like this will cause failure every time. Another reason could be poor installation, where catalytic converter gaskets have not been replaced with the new converter. Fuel and engine additives can cause converter failure, some of these additives are not oxygen-sensor safe. Using the wrong fuel specified for your vehicle will cause the same effect. If your vehicle calls for an 89 octane, then using a 93 octane is bad for your vehicles engine, exhaust system and the catalytic converter.
Restricting the exhaust can cause converter failure. A lot of people will change the factory exhaust with a smaller or even larger exhaust system or tip. The same goes for air injection systems. Ignoring your air filter, ignition parts, such as spark plugs and spark plug wires, can have an effect on your converter. If you take care of your vehicle and stay within the vehicle manufacturer's guidelines for fuels and maintenance, you will find your vehicle performs well.
Ever wonder why catalytic converters are so expensive? Materials and metals such as ceramics, platinum, rhodium and palladium help make up the core of the converter.
Most vehicles are equipped with one of two types of catalysts: oxidation catalyst or the reduction catalyst. The ceramic core is coated with these metals to help with oxidation and carbon monoxide burn off. Although some vehicle manufacturers use different methods and components, just about all use an oxygen sensor, which is mounted in front of the catalytic converter. The oxygen sensor sends a signal to the computer which relays the amount of oxygen in the exhaust. The ideal fuel/air ratio is 14.7 to 1. Sometimes vehicles will run rich or lean, meaning the fuel/air ratio is wrong. When the oxygen sensor relays the amount of oxygen to the computer, the computer will make the proper adjustments to create a cleaner exhaust.
Not everyone knows or understands the purpose of a catalytic converter. It's meant to convert harmful hydrocarbons, nitrogen oxides and carbon monoxide into less harmful compounds. The catalysts inside the catalytic converter convert carbon monoxide and hydrocarbons into carbon dioxide and water, and nitrogen oxides back into nitrogen and oxygen. With so many vehicles producing extremely harmful exhaust, our oxygen would be depleted without the catalytic converter. A lot of smog and the haziness seen in big cities is caused partly by the toxic fumes emitted from our vehicles.
|Jennifer Mathes, Ph.D.|