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Does removing catalytic converter increase fuel consumption
by Alex
Expert answer:
Quick answer
Removing a catalytic converter generally doesn’t improve mileage and may harm performance. Often, it can trigger issues that worsen mpg and is illegal in many areas.
Detailed answer
A catalytic converter reduces harmful emissions by converting pollutants to less harmful substances. Some drivers believe removing it frees up exhaust flow for more power and better economy. In modern cars, this rarely pans out.
Engines depend on correct oxygen readings. With the cat gone, sensors may misread and adjust fuel mixture incorrectly, sometimes causing worse mpg or a rough running engine. You’ll likely face check-engine lights or fail emissions tests. Plus, removing emissions equipment is illegal in many jurisdictions.
Even if you gain a tiny horsepower boost in older vehicles, the cost—environmental harm, potential fines, and possible engine inefficiencies—outweighs any minor performance perk. For daily drivers especially, it’s best to keep the catalytic converter intact for stable fuel consumption and legal compliance.