Catalytic Converter (CAT)

Compiled by Chris Hugo, Powerflow Durban North

What is a CAT?

It is an emissions control device that converts toxic gases and pollutants in the exhaust to a less toxic pollutant by catalysing a redox reaction (Reduction).

How does a CAT work?

In order to reduce air pollution, modern vehicles are equipped with a catalytic converter that reduces emissions of three harmful compounds found in car exhaust: Carbon monoxide (a poisonous gas) Nitrogen oxides (a cause of smog and acid rain) Hydrocarbons (a cause of smog).

A catalyst is a chemical that causes a reaction between other chemicals without having any effect on itself. The whole purpose of the catalytic converter is to convert the pollutants from harmful gasses to a more environmental friendly gas through the tail pipe at the rear of your vehicle.

Vehicles fitted with catalytic converters emits most of their total pollution during the first fifteen minutes of engine operations, reason for this is that the CAT hasn't reached its operating temperature which is about 700 degrees Celsius.


StructureDefinition
HCHydrocarbon
COCarbon Monoxide
NO2Nitrous oxide
O2Oxygen
H2OWater
CO2Carbon Dioxide
N2Nitrogen

Benefits of having a CAT

The catalytic converter's sole purpose is to reduce the amount of harmful pollution produced by the combustion of hydrocarbon-based fossil fuels in cars.

Fun Fact

Catalytic converters decrease hydrocarbon emissions by about 87 %, carbon monoxide by 85 %and nitrous oxide by 62 % during the maximum efficiency.

Effectiveness

Initially, automakers believed the catalytic converter would make cars prohibitively expensive. On the contrary, catalytic converters only add about two percent to the cost of a vehicle. In 1985, the Environmental Protection Agency estimated that catalytic converters saved at least 10 times more in health costs than the price of a catalytic converter.

Disadvantages

Catalytic converters decrease the fuel efficiency of a car and the increased price of unleaded gas costs consumers more in the long run, when the catalytic converter malfunctions it can also cause severe back pressure that will cause the motor to run rough and struggle to start, and over a period the engine will lose power at a increasing rate and the vehicle will go into limp mode.

Catalytic converters do block over time with carbon particles which leads to total immobility of the vehicle, it is a very costly procedure to replace especially if the CAT is part of the engine manifold. The rate at which blocking takes place is entirely dependent on driving conditions, City driving or short distances accelerates the blocking process as the CAT does not reach operating temperature for long periods of time resulting in carbon build up.

Benefits of removing a CAT?

Cats can be removed without complications on older vehicles, however later models will invariably require software changes to delete the non cat reading form the ECU this is a safe operation with continuous long term engine performance benefits.

More Fuel Options

Vehicles equipped with catalytic converters run only on standard fuel, which produces more power and better engine combustion but it can quickly destroys the inner catalyst materials of catalytic converters. A car with no catalytic converter will be able to run on a variety of fuels 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 a catalytic converters converts 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.

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.

Should you wish to discuss any particular technical issues about your exhaust system we at Powerflow Durban North would gladly oblige. Pay us a visit with your car to enable us to inspect and advise.