Does the Absence of a Catalytic Converter Affect Fuel Consumption?

[Jodie]

The absence of a catalytic converter does not affect fuel consumption. From the entire working process of the catalytic converter, its primary responsibility lies in exhaust gas treatment, and therefore, it has no connection with the vehicle's fuel consumption. Precautions for Using a Catalytic Converter: Apart from failure, a catalytic converter may also become clogged. If the catalytic converter is clogged, the engine may experience insufficient power and increased fuel consumption, which requires attention. Removing the catalytic converter can significantly affect the engine's low-end torque, and during daily driving, higher RPMs may be required to compensate for this deficiency, which indirectly increases fuel consumption. If the catalytic converter is removed, the reduction in exhaust pressure will ultimately lead to a decrease in the vehicle's low-end torque. Factors Affecting Vehicle Fuel Consumption: Vehicle Weight: There are many factors that affect fuel consumption, the first being the vehicle itself, such as its weight. The heavier the vehicle, the higher the fuel consumption. Tire Pressure: Low tire pressure increases fuel consumption. Engine: Dirt and oil buildup on the engine's surface can affect heat dissipation, leading to increased fuel consumption. Transmission Carbon Buildup: Carbon buildup in the transmission can reduce engine power and, to some extent, be accompanied by increased fuel consumption.

[McHarley]

I tried removing the catalytic converter before, and the car's exhaust sound became louder, but fuel consumption actually increased. Since the catalytic converter is responsible for purifying exhaust gases, removing it eliminates backpressure in the exhaust system. With the engine exhaust flowing too freely, the combustion balance gets disrupted. When the oxygen sensor detects abnormal oxygen levels in the exhaust, the ECU automatically compensates by injecting more fuel. Over time, this can increase fuel consumption by 1-2 liters per 100 kilometers. Moreover, after removing it from an older car, the low-end torque becomes weak, requiring deeper throttle presses when starting off, which further drives up fuel consumption. My suggestion is not to remove it—the small amount of fuel savings won't cover the repair costs later.