The Ins and Outs of Every Engine
What you need to know about the stuff that goes in and out of an engine, and an affordable way to get more power. Kinetic energy creates movement in objects and propels them into motion. For automobiles, such energy is the result of combustion. Oxygen and fuel are ignited by an electrical spark, which produces the heat energy that drives the engine. Because atmospheric air contains dirt and dust particles, filters are used to keep these nasty bits out to reduce excessive wear and tear on the engine.
To achieve good fuel efficiency, manufacturers often equip vehicles with an air intake chamber known as an air-box. It contains a filtration element that is sometimes restrictive and doesn't allow the engine to "breathe" freely at higher RPMs. However, more combustible air means more power, so a very basic way to extract more power from your automobile is to replace the standard filter with an aftermarket one designed to enhance performance. It allows freer airflow into the engine and improves performance because combustion requires oxygen. Such aftermarket filters include a 'drop-in' air filter (this replaces the factory piece within the air-box) or an 'open pod' filter paired to an intake pipe which replaces the entire air-box installation. But because what goes in must come out, there are exhaust gases from the combustion of fuel that must be released.
The first part of an exhaust system is the exhaust manifold or 'header' (or 'extractor'). Exhaust gases flow from the cylinder head, through the exhaust manifold and to the tail pipes. Typically, the exhaust manifold is shared by all the cylinders, which can create unwanted backpressure and lead to a slight loss in performance. Backpressure needs to be minimised because it's an opposing force acting against the piston when it pushes out exhaust gases. Efficiency suffers since the piston requires more force to overcome the resistance. Furthermore the standard manifold (straight from the carmaker) is typically designed with all the cylinder's exhaust gases fed into one pipe. It's a simple and cost-effective design, but there are aftermarket headers with individual pipes for each cylinder, each one specifically engineered to suit the pulses of exhaust gas from the engine and help them flow much more freely. And because it's the muffler's job to silence an engine, if you keep your standard but swap your exhaust manifold for an aftermarket header, you're unlikely to get much extra noise.
Imagine jogging with something that restricted airflow both in and out of your lungs - a restrictive intake and exhaust system has exactly the same implications for your car's engine. Ultimately, it helps to think of the intake and exhaust systems of a car as two components in one system. Swapping out these components for aftermarket alternatives for better engine breathing is a great way to give your car extra oomph!
To read more on how you can further improve your car engine and enhance performance, please click here.
This article is written by Leow Julen, contributing writer for Top Gear Singapore, and Samuel Kang, editor for Rev magazine.