In the exhaust system modification, exhaust system modification is more popular, because the exhaust system especially the tail section, not only exposed on the outside of the vehicle is clearly visible, but also can send audio and sound overwhelming, is one of the few can be directly converted part of the owners to provide visual and auditory dual sensory stimulation. Due to the limitation of cost, noise pollution and different emission standards, the exhaust system of the original plant will be very conservative in design, and to a certain extent, it will limit the performance of the engine due to the low exhaust efficiency. Therefore, the modification of the exhaust system can also often bring unexpected gains to the owners.
(1) the refitting of the exhaust system can follow the way from shallow to deep
1) general exhaust system modification involves only the tail section of exhaust pipe, and the diameter of exhaust pipe tail and the structure of muffler should be increased appropriately, so that the airflow passing through the unit area will increase, so that the exhaust emission will be smoother. The most basic modification is to put a more beautiful stainless steel sheath on the end of the exhaust pipe, which has the advantages of low price, convenient installation and no influence on the original vehicle.
2) deep modification can be sawed off the original car exhaust pipe of the tail section, the cut-off position welding special tail throat, or directly replace the original special vehicle tail throat launched by different brands. The tail throat is made of stainless steel, and its biggest feature is that it can make a low frequency sound, though the sound quality is low, it is very refreshing. But if this kind of modification is adopted, the owner of the car must give up the tail section of the original exhaust pipe of the original car.
3) deeper modifications are focused on the middle of the exhaust pipe and the exhaust manifold. The modification of the middle section in the front of the exhaust pipe involves the modification of the inner wall and diameter of the three yuan catalytic converter and the exhaust pipe, and the modification of the exhaust manifold involves the arrangement of the exhaust lines.
(2) the modification of the different parts of the exhaust system
1) exhaust manifold. The exhaust manifold modification is generally the most expensive part of modification of the exhaust system, because of the strict requirements of the length, diameter and curvature of blind, so its development and production costs are high. But the excellent design of the exhaust manifold plays an important role in the sipping effect of the whole exhaust system. General on the four cylinder engine models, the exhaust line arrangement is divided into two kinds: "four one" (4-1), and the four exhaust manifold four cylinder engine out of the direct linkage part a summary to the exhaust pipe of the pipeline design; "four two a (4-2.1)", two first aggregated into the exhaust manifold a tube, and a section of the expansion chamber to reduce the pressure of the exhaust gas from the exhaust gas of the two part, summary diverted into a final exhaust pipe. The traditional concept is "design" of the four would be more suitable for the high speed gas fluctuation frequency, helps to enhance the dynamic performance in the car at high speed; and the "four two design" is more conducive to the output torque at low speed, so it is suitable for daily use for car city conditions. But now many of the latest design "and a two" exhaust manifold can improve the performance of the engine in the middle and high speed, so it can meet the full range of users requirements. In addition, the modified method of four two ", the need to remove the original exhaust pipe, exhaust pipe installation of new, this time as a better choice of exhaust pipe, the exhaust efficiency can get the" exhaust sound and high charm ", while also taking into account the appearance and durability.
2) a three element catalytic converter. The three way catalytic converter is an important device to control harmful components of exhaust gas. It mainly purify the harmful gases such as hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxides (NOx) in engine exhaust. There are many modifications taking as much as possible in order to reduce the exhaust resistance, three yuan will be catalytic converter forcibly removed, it will not only make the vehicle emissions exceed the standard, may also make the car part of a self diagnostic function of automobile ECU send the wrong signal, affect the normal traffic, it is recommended that three yuan to retain the original vehicle catalytic converter. Now, many new three way catalytic converters will not block the exhaust flow rate, and can be changed to a modified high-performance three way catalytic converter, but the price is higher.