Beginners guide to tuning

Exhaust Parts

The basics of exhaust tuning are in the increase of exhaust efficiency but it is not right to assume that the least resistance leads to the highest efficiency. By removing the muffler, exhaust resistance is radically reduced but engine torque is also reduces, adversely affecting launch and vehicle acceleration so it is necessary to have just the right amount of exhaust back pressure (resistance). Exhaust manifolds are a good example of this where it is possible to change the characteristics of the engine with the shape, joins and lengths of the manifold. The exhaust system plays a vital role in the exhaust emissions and sound levels of the car. Stock mufflers tend to have tight bends and crushed areas in order to reduce production cost and layout reasons. The emphasis on the design is to reduce sound levels and gain torque at the lowest engine speeds. Sports mufflers have smoother bends to increase the efficiency of the exhaust system and each system is tuned to the specific car so that sports cars can have efficient power all through the rev range, whilst sedan and wagon cars will have more emphasis on producing torque. Sound is also tuned to suit the application whilst giving enough to state its presence. Turbos (more details later) use exhaust energy to produce power and so become a resistance in the exhaust system and so mufflers for turbo power cars are designed with less resistance compared to NA vehicles. Dependant on the Vehicle Type and muffler, it is possible to raise boost levels and gain big power increases.

Stock Muffler
Sports Muffler

Metal Catalyzer improved both exhaust efficiency and Cleansing Properties

Stock CatalyzerMetal Catalyzer

The catalyzer cleans the exhaust gasses so that they are less harmful to the environment. A catalyzer has a fine mesh structure with many tiny holes causing a resistance to exhaust gas flow. When considering only exhaust efficiency, best results would be achieved by the removal of the catalyzer but this would release many harmful gasses into the atmosphere and make the exhaust sound very loud. For these reasons the removal of a catalyzer from a vehicle is prohibited by law in many countries. In order to overcome this issue, the HKS 150 cell metal catalyzer was developed which has a much coarser mesh (cell) design allowing more efficient exhaust gas flow whilst maintaining cleansing properties through innovative design combining performance with social responsibilities.


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