Increased Horsepower
Cars that have their catalytic converters removed experience an increase in engine horsepower. Catalytic converters create a significant source of engine back-pressure due to the constrictive effects they have on exiting engine exhaust gases. Removal of catalytic converters from cars allows exhaust gases to exit their engines much faster and at higher levels.
Better Gas Mileage
Since catalytic converter removal allows for exhaust gases to exit a car's engine at increased speeds, engine back-pressure is reduced, which lessens engine strain. This reduction in engine back-pressure and engine strain enables an engine to work more easily, and thus reduces fuel consumption and increases gas mileage.
Lower Engine Operating Temperature
Since removing a catalytic converter lessens the burden on a car's engine by enabling engine exhaust to vacate the engine more easily, a net effect is a reduction in engine operating temperature. The more easily an engine functions and the less work it has to do results in less friction, less load and, ultimately, a lower operating temperature.
More Fuel Options
Cars equipped with catalytic converters run only on unleaded gasoline. Lead-based gasoline, which produces more power and better engine combustion, quickly destroys the inner catalyst materials of catalytic converters. A car with no catalytic converter will be able to run on a variety of lead-based and/or high-performance fuels that would not be possible with a catalytic converter.
Healthier Exhaust Sound
Catalytic converters operate like car mufflers, whose sole purpose is to muffle the sound of exiting engine exhaust gases. Although catalytic converters burn unburned exhaust gases exiting an engine, thus making tail pipe emissions cleaner, they also further muffle a car's exhaust sound and bestow a somewhat timid, tempered exhaust sound. Without a catalytic converter, a car's exhaust sound becomes a little louder, a little deeper and more distinctive.
Read more: What Are the Benefits of Removing the Catalytic Converters From Cars? | eHow.com
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