What are the effects of removing the catalytic converter from a car?
4 Answers
The removal of the catalytic converter from a car will result in excessive exhaust emissions, reduced exhaust purification function, increased exhaust back pressure, increased fuel consumption, decreased power, high-temperature sintering and blockage, environmental pollution, and fault codes in models equipped with oxygen sensors, making the car fail annual inspections. The catalytic converter is a device in a car used to purify exhaust gases. It enhances the activity of exhaust substances, converting some harmful substances in the exhaust into harmless substances that are expelled from the vehicle, thereby reducing atmospheric pollution. Since it does not participate in the reaction itself, it neither consumes nor ages. However, it is often damaged during daily use, mainly in three forms: catalyst poisoning and failure, catalyst blockage, and catalyst breakage. The catalytic converter has oxygen sensors. Removing it affects the closed-loop control of oxygen concentration, impacting the ECU's control of fuel injection and throttle opening. The oxygen sensors detect oxygen levels and feed the signal back to the engine control unit to adjust fuel injection. If the catalytic converter is removed, the engine will not receive the correct exhaust signal, leading to issues. For example, the engine control unit may judge the mixture as too lean, increasing fuel injection and making the mixture too rich, thereby increasing the car's fuel consumption. After removing the catalytic converter, such a vehicle is not allowed to be driven on the road, as it is considered illegal.
Removing the catalytic converter is a big deal. The car's exhaust flows as freely as a floodgate opened, throttle response becomes quicker, and acceleration feels more aggressive, especially at low RPMs. However, there are many downsides: the exhaust becomes extremely foul-smelling, with a strong sulfur odor—standing behind the car is unbearable. Emissions also fail to meet standards, making it impossible to pass environmental inspections, and you'll likely have to reinstall it for annual checks. After removal, the engine computer constantly throws errors because the oxygen sensors get confused, with the check engine light frequently turning on. Long-term, it harms the engine—uneven exhaust pressure can cause internal damage, leading to costly repairs. So, it's really not recommended; the sacrifices for a bit more power are too great.
If you ask me about the changes after removing the catalytic converter, the first noticeable difference is the exhaust sound. It becomes much louder with a strong buzzing noise, especially at high RPMs, which is really annoying. The throttle response does feel a bit lighter, and there's a slight improvement in power, but these minor benefits aren't worth it. After removal, the exhaust fumes smell terrible—so bad that it can make you dizzy when idling. Even worse, the engine becomes prone to issues. The higher exhaust temperatures can damage the oxygen sensors, and within a few days, the check engine light will likely come on. During annual inspections, there's a high chance it won't pass—not only due to excessive emissions but also because the environmental authorities may fine you if caught. When you do the math, the repair costs might exceed any savings on fuel. Honestly, it's better to leave this component untouched.
Removing the catalytic converter makes the exhaust fumes noticeably pungent, lingering in the garage for half a day. The car does accelerate a bit faster, especially with more immediate throttle response at low RPMs. But the engine noise becomes as loud as a modified car, buzzing and rattling the ears. Over time, the excessive exhaust temperature can easily damage the oxygen sensors, costing hundreds to repair each time. Environmentally, it's even worse—emissions are completely non-compliant, making it impossible to pass annual inspections. There are also safety hazards, like the risk of exhaust leaks igniting flammable materials. In short, aside from a slight power boost, it's all downsides.
