Exhaust fumes generated by your cars engine are emitted from the engine is greatly high temperature and high pressure. Once exhaust gasses touches air, it rapidly expands and causes that familiar exhaust sound by vibrating air. To avoid this, exhaust systems gradually expand fumes, and fumes’ pressure and temperature get lower and reduce this sound. This is why a vehicle without a muffler or full exhaust sounds significantly different to a car with an exhaust.
Lets take a quick look at how JDM exhausts work
It is also why OEM exhausts and aftermarket exhausts have significantly different audio properties. Exhaust systems also purify/clean exhaust fumes as well as adjusting sound volume and quality. Those are the two primary purposes of exhaust systems. Aftermarket JDM sport mufflers like Fujitsubo have higher performance, offering more power and torque, tuning exhaust sound, over traditional OE exhaust systems – the sound of a tuners car tends to be quite important to drivers. Exhaust systems are a combination of an exhaust manifold, a front pipe, a catalyzer, a main pipe, and a silencer. Lets look in detail at how the different parts of exhaust systems work together.
Exhaust manifold to front pipe
The exhaust manifold funnels the exhaust output of two or more cylinders into a single pipe. Stock exhaust manifolds are often designed in a less that efficient way, in order to save costs on materials and manufacturing. Engines typically have two exhaust manifolds (one each side) but less or more are also possible depending on the number of cylinders and engine design.
NA cars: NA means naturally aspirated, this refers to cars with no turbo or supercharger. An exhaust manifold gathers exhaust fumes of cylinders and forwards it to the catalyzer.
Turbo cars: The exhaust manifold gathers exhaust fumes of cylinders and forwards it to a turbine.
If shape of an exhaust manifold is not good, it prevents exhaust gasses from moving smoothly and may decrease an engine’s output. 4 cylinder model has two types of gathering fumes. One is gathering fumes gradually from 4 to 2 to 1, and the other is gathering fumes from 4 to 1 at once. Generally the former is suitable for low to middle speed, and the latter is suitable for high rotation. However, this is just a general example, and there are exceptions based on characteristics of JDM cars.
Turbo cars have a front pipe, which carry fumes emitted from a turbine to a catalyzer. If a front pipe is designed to make smooth stream of gasses, response of turbo improves.
As you will see by the end of this page, exhausts are all about smoothing the flow of gas from the engine to the outside of the car.
A catalyzer is the cleaning equipment of exhaust fumes. A simpler term would be a filter. It it commonly referred to as a “catalyzer” instead of its full name, a catalytic converter. Think back to highschool science, a catalyst helps speed up reactions – in the case of a catalytic converter the unit converts carbon monoxide, hydrocarbons that have not been burned in the engine and oxides of nitrogen to less harmful substances. Converters must be replaced as the internals react to convert poisonous gasses. By carrying exhaust fumes emitted from an engine to a catalyzer, a catalyzer filters toxic substances like CO, HC, and NOx into much less toxic substances.
Diameter and design of a main pipe greatly influence characteristics of an engine by reducing exhaust back pressure. Generally a pipe with large diameter increase exhaust efficiency because exhaust resistance decreases. However, a pipe with too large diameter decreases torque due to gas rotation in the middle of the pipe – think letting water out of the bath. A main pipe with too small diameter improves torque but exhaust resistance increases and output performance decreases. To produce a pipe with appropriate diameter and design is the key. Each car model has different designs and characteristics, and so leading exhaust manufacturers like Fujitsubo, HKS and Mugen continuously research and develop JDM exhaust systems for the highest quality.
Releasing exhaust fumes directly into the atmosphere from the exhaust system usually causes very loud sounds. This annoys people and in some countries is illegal.
A silencer decrease the volume of exhaust sound, and it tune exhaust sounds, making them nicer to the ear and not as harsh. To create the best performance of efficiency and quieting effects, high performance exhaust silencers are strictly designed for each car model. For example, one of the best JDM exhaust manufacturers, Fujitsubo, has three types of silencers, and they apply the best one for each car’s characteristics.
This is how JDM exhaust systems work. You now know how aftermarket high performance exhausts are better than OE ones in a lot of ways. Intuneautos offers high performance JDM exhaust systems from Fujitsubo, HKS, Mugen and other major manufacturers by competitive prices, and all the products are shipped directly from Japan. Shop online at intuneautos and upgrade your exhaust systems now.