13 Removing Catalytic Converter Pros and Cons

The catalytic converter is responsible for the ignition and burning of engine exhaust gases which remain after the initial reaction occurs. This product became standard equipment in the U.S. for all vehicles with the 1975 model year. They help the exhaust gases become cleaner without a significant impact to the performance of the vehicle.

The catalyst in this device uses platinum and palladium to turn the initial exhaust created by the engine into gases which are less harmful to the environment. Each vehicle releases hydrocarbons, carbon monoxide, and nitrogen oxides during the combustion process. The catalytic converter then turns the carbon monoxide into carbon dioxide while the hydrocarbons become CO2 and water. The nitrogen oxides become oxygen and nitrogen.

Although this is a clear benefit compared to what is normally created, the high levels of carbon dioxide still create a greenhouse gas issue. If you remove the catalytic converter, then this conversion process disappears.

Here are some of the other pros and cons associated with the removal of a catalytic converter.

List of the Pros of Removing a Catalytic Converter

1. Your exhaust sounds better.
The catalytic converter works like a muffler on the average vehicle. Its job is to reduce the impact of the gases emerging from the engine due to the combustion and burning of fuel. This action muffles the sound of your exhaust in combination with the muffler on your vehicle. When the catalytic converter is no longer present, then the sound your vehicle emits is louder. (This is a possible “con” as well, depending on your viewpoint. See below.)

2. You can generate more horsepower without it.
Once the catalytic converter is removed from a vehicle, some models do experience a significant increase in power. This advantage occurs because the unit creates a source of back-pressure on the engine. It uses constriction as a way to impact the exhaust gases before they leave the vehicle’s system. Since the gas releases through the exhaust with added speed when the catalytic converter is not present, the engine can perform with its maximum potential since there is nothing left to hold it back.

3. You have access to more fuel options.
Up until the 1990s, fuel stations in the United States offered leaded and unleaded gasoline for sale. That’s because the presence of a catalytic converter eliminated the option of using a leaded fuel. When you take away this device, you have access to several additional high-performance fuel options for your engine that you wouldn’t be able to use otherwise. If you were to run leaded fuel through a catalytic converter, it would destroy the materials inside, rendering the vehicle useless.

4. You can operate the engine at a lower temperature.
When constriction occurs during the exhaust process, the extra work that the engine does to generate power creates more heat under the hood. By removing the catalytic converter, you remove this constriction, which means you can operate at a lower operating temperature. You’ll experience the benefits of less friction and load with the unit gone too, which can reduce the overall wear-and-tear on the vehicle over time.

5. You can achieve better gas mileage.
Since the catalytic converter places a strain on the engine with its constrictive design, it must work harder to achieve the same energy than it does without the device in place. Removing it lessens this burden, creating a net effect where the engine can perform significantly better without working as hard. That means you receive an improvement in fuel consumption which translates to an improvement in your overall fuel economy. Many have said the mpg gain is slight.

6. You can do it yourself.
Anyone with some decent car sense and a few tools can take care of removing their catalytic converter at home. All you need to do is follow these three steps.

• Uncouple the O2 sensor on your vehicle. You can do this if you have an O2 wrench available. Most auto parts stores have them or you can order one online.
• Pull off the catalytic converter next, separating it from the exhaust system. You’ll need to unbolt the device first, then slide it down your exhaust pipe. Some units are welded to the vehicle, so you’ll need to saw it off.
• Restore the exhaust system by creating a straight pipe to facilitate removal of the exhaust gases.

List of the Cons of Removing a Catalytic Converter

1. You cannot perform this action legally in several U.S. states.
You must follow a specific process to legally remove your catalytic converter in the United States. These guidelines are offered through 1986 rules that were issued by the Environmental Protection Agency. Several states, such as California, have strict laws on the books which prohibit the removal of a catalytic converter under most circumstances. Unless you know for certain what the outcome would be, speak with your mechanic about the pros and cons of removing this item before doing it on your own.

Federal law in the United States prohibits the removal of a catalytic converter which is functioning properly. A replacement converter is permitted if there is a documented failure of the original one. Serious fines may result if your vehicle is found to be without this device.

2. You may trigger a fault code in your vehicle.
Removing the catalytic converter may create a circumstance where you trigger a fault code in your vehicle. If you have a check engine light, then this will illuminate on your heads-up display. Although you can get around this issue on some vehicles by fitting a spacer on your downstream O2 sensor (the lambda sensor), there is a risk that normal functionality does not return. That would make it a challenge to track actual faults through this warning light.

3. You would create an emissions concern.
The goal of the catalytic converter is to remove the high levels of carbon monoxide created through fuel combustion to replace it with carbon dioxide. You want this device to scrub these gases for you because they contribute to global warming issues, acid rain, ocean acidification, and other forms of environmental damage.

There is the concern that the fumes from your exhaust could reach the vehicle cabin too. If you have an exhaust leak or you drive with the windows down, your lungs won’t appreciate the carbon monoxide. It may do more than induce a headache. It could create life-threatening situations in some circumstances.

4. You will create more noise when you drive.
Although the sound of an engine which is not held back by a catalytic converter sounds healthy, it can also become unhealthy from a noise perspective. If you have the windows down and the engine full, you might exceed 110 decibels without this device. Any noise above 85 decibels is potentially dangerous to your hearing health. Even if the noise isn’t bothersome after the unit is gone, the lack of noise suppression may interfere with conversations, becoming annoying after a lengthy drive, or cause noise complaints while you idle at home. (This is a possible “pro” as well, depending on your viewpoint. See above.)

5. You may use more fuel without a catalytic converter.
The catalytic converter does more than convert harmful gas into something less dangerous. It also squeezes a better fuel economy out of some vehicles.  However, some people have reported that once they remove this device, they discover that their miles or kilometers per gallon actually go down.  The most common explanation seems to be that they are burning more gas because their O2 sensors are not reading correctly and therefore requiring more fuel usage.  Relatedly, there are reports that a notable amount of backpressure is lost.

6. You won’t pass a visual inspection for your vehicle.
If your vehicle must go through an emissions test, then it is essential to remember that there is a visual test in addition to the performance evaluate. When there isn’t a catalytic converter as part of your exhaust system, then your car will fail. Testers are usually required by law to report failures like this, which means an uncomfortable conversation will be waiting for you when you try to drive away. A failure may cause your vehicle to be impounded too.

7. You will lose your low-end torque without a catalytic converter.
The catalytic converters in the past were very restrictive because the exhaust coming from the combustion process was extremely toxic. Modern engines create less of an impact, which means the device creates almost the same effect as a straight pipe for the average vehicle on the road today that is less than 10 years old. If you decide to remove the catalytic converter, then you’ll experience a loss in your low-end torque while operating the vehicle. Your horsepower gains will be slightly better when you run full out. Since this is only legal for off-road vehicles, the benefits may not be the type you want.

The pros and cons of removing the catalytic converter from a vehicle involve performance and aesthetics at the cost of dangerous gas production. Most modern vehicles that are used for daily driving will see a minimal change to their performance by getting rid of this device. You’ll be paying more for fuel if it is gone while running the risk of fouling the air in your cabin. That’s why choosing this course of action is something that you do at your own risk.

About the Author
Brandon Miller has a B.A. from the University of Texas at Austin. He is a seasoned writer who has written over one hundred articles, which have been read by over 500,000 people. If you have any comments or concerns about this blog post, then please contact the Green Garage team here.