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How To Boost Your Car’s Performance With An Aftermarket Exhaust System

What Is An Exhaust System?

The gasses produced after the combustion of fuel and air has taken place, needs to be removed from the engine cylinder. This gas contains chemicals such as NOx, CO and unburnt hydrocarbons which are harmful to the environment and pedestrians. There is also a lot of noise created which is typically unfavourable. The exhaust system eliminates all these factors via the following components:


Exhaust manifold: It is attached to the engine cylinders and carries the exhaust gases from the cylinder to the other exhaust components.


Catalytic Converter: The harmful gases produced on combustion are converted via this device to less harmful chemicals such as NO, CO2, O2, and H2O. The catalytic converter in the vehicle is an essential and mandated part of the vehicle since it is responsible for the elimination of toxic chemicals which can affect the environment and the people. 


Muffler: The extremely unbearable sound produced by the combustion is reduced by the muffler using sound deadening porous elements.


Exhaust Pipes: It is responsible for carrying the gasses from one component to the other and finally outside the vehicle via the tailpipe. 

How Does The Exhaust System Affect Engine Performance?

The engine works by throwing the piston into the power stroke with the energy created by the combustion of the fuel and air mixture. The piston in turn moves the crankshaft which transfers the energy to the flywheel and transmission and ultimately to the wheels. To obtain greater horsepower or increase the engine performance it is necessary for the piston to undergo the power stroke movement with as much downward force as possible and there should not be any restrictions produced by any parameter opposing that movement. Now as the engine goes into the power stroke, what follows is the exhaust stroke where the piston is required to push out the remnants of the combustion from the fuel and air mixture. 

As the exhaust gases move through the exhaust valve into the exhaust manifold, there is a high-pressure area created at the valve opening and a low-pressure area at the manifold, this low-pressure area forces the gases to leave the exhaust. But the design of the manifold significantly affects the pressure build-up and if there is a high-pressure area created at the manifold, this will restrict the flow of gases into the manifold creating what is called Back-Pressure. This back-pressure can decrease the performance of the engine by restricting the movement of the piston and therefore reducing the engine performance. 

Therefore, the exhaust stroke must be done efficiently and effectively by eradicating any back-pressure created by the exhaust manifold. When the fumes are leaving the cylinder from the combustion chamber, the path it follows via the manifold and through to the other exhaust system components affects the engine performance greatly. 

Now if the manifold has a very large diameter to accommodate all the gasses to flow through to the exhaust pipes, during high RPM, when more exhaust gasses are pumped, the manifold will have a large enough opening that will allow the gasses to flow smoothly whereas during low RPMs this large opening will mean there is too much area for the gasses to move about which will create a high-pressure area in the manifold instead of the combustion chamber causing back-pressure which will decrease performance. 

On the other hand, if the manifold tubes were very narrow, during low RPMs the exhaust flow would be favorable but at higher RPMs the narrow opening of the pipe will restrict the flow of gasses again causing back-pressure and reducing engine performance. 

Having tapered manifold openings can be one way of eliminating the above scenario to a certain extent which is what most performance exhaust feature. 

Top Selling Exhaust System Manufacturers

Dorman is a top supplier of original equipment dealer “exclusive” automotive and heavy-duty replacement parts, automotive brake parts and hardware, exhaust system parts and fasteners to the Automotive and Heavy Vehicle Aftermarkets while also maintaining the supply of household hardware and organizational products to mass merchandisers. Dorman has believed in giving repair professionals and vehicle owners greater freedom to fix cars and trucks by releasing more exclusive, cost-effective and labor-saving replacement solutions than anyone else. 

Walker is the world’s largest manufacturer of OE and Aftermarket exhaust systems and emissions-control products and is an OE supplier to many major manufacturers. Walker has the technical excellence needed to meet today’s requirements while providing solutions for tomorrow’s challenges. All Walker exhaust parts, from premium CalCat converters to Quiet-Flow mufflers, are designed with great attention to detail to meet all standards and customer demands. You can also go with Walker performance exhaust parts if you want to get the ultimate in function and sound.

Walker offers quality direct-fit and universal converters that comply with EPA and CARB requirements. There are essentially two types of Catalytic Converters


Two-Way Catalytic Converter:

  • Allows oxidation of CO (Carbon Monoxide) to less-harmful CO2 (Carbon Dioxide)

  • Allows oxidation of HC (Unburned Hydrocarbons) to CO2 (Carbon Dioxide) and H2O (Water)

In this design, exhaust gases are directed to flow through the substrate containing precious metals platinum and palladium, which allow the chemical reaction to occur. The exhaust gases increase in temperature as the conversion process takes place. Because of the intense heat created by this process, exhaust gases leaving the converter should be hotter than the gases entering the converter. This also explains why heat shields are required on most units. Two-way converters operate relatively efficiently with a lean fuel mixture. Ineffectiveness in controlling NOx led to the introduction of three-way converters.


Three-Way Catalytic Converter:

  • Allows reduction of NOx (Nitrogen Oxides) to N2 (Nitrogen) and O2 (Oxygen)

  • Allows oxidation of CO (Carbon Monoxide) to less-harmful CO2 (Carbon Dioxide)

  • Allows oxidation of HC (Unburned Hydrocarbons) to CO2 (Carbon Dioxide) and H2O (Water)

Three-way converters have been used in vehicle emissions control systems in North America - and many other countries - since 1981. The three-way without air uses advanced catalyst chemistry to store and release O2, in conjunction with an O2 monitoring and control system. This system utilizes one or more O2 sensors to oscillate the fuel mixture between lean and rich conditions. This oscillation, combined with the O2 storage and release on the catalyst surface, allows for optimum reduction of all three emissions. These converters are used in conjunction with OBDII diagnostic systems on today's vehicles. This system alerts the driver when the converter is not working at peak efficiency. 


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