The improved exhaust pipe usually means that the whole process of exhaust can be shortened, and even the purification devices such as automobile muffler can be removed. It is hoped that after the modification of the middle and front end of exhaust, the acceleration of the automobile will become faster, the power will become sufficient, the dynamic auditory effect of engine work will refuse to explode the street.

If you want to change the exhaust, I have some suggestions here. First, determine your psychological expectations and budget. What do you want, how much do you want to spend, how many more questions are acceptable, and so on. Just want to listen to a simple voice, or want to change a look, or competition, or what.

2. Learn more about products,

Experience all aspects of the product and what you focus on, such as sound, appearance, etc.

3. Try to choose exhaust with valves and brands.

4. Don't choose the beast roar of hundreds of dollars.

5. Do not let your exhaust gas affect others' rest.

What is the structure of the whole exhaust pipe? What is the principle of the change of exhaust pipe sound? And why does the master say that the improved exhaust will lose low torque?

1. Composition of automobile exhaust pipe.

It is used to collect exhaust gas, that is, automobile exhaust pipe. Its main components include exhaust manifold, exhaust pipe, exhaust temperature sensor, catalytic converter, automobile muffler and exhaust pipe.

1.1 exhaust pipe.

The position connected to the exhaust port of each cylinder of the engine. The main function of the system is to collect the exhaust gas passing through the exhaust port of the cylinder head and transmit it to the exhaust manifold, which is equal to the beginning of inhalation and exhalation. The resistance to exhaust in this process must be minimized to reduce the interaction between cylinders, so that the exhaust can be discharged smoothly（ Some people have mentioned variable intake technology before. In fact, this is mainly done here. Adjust the length of the intake manifold by controlling the opening and closing of the valves in the air chamber. At high speed, the length of the intake manifold can be adjusted according to the working conditions of the engine, the amplitude of stepping on the accelerator and the torque requirements of the engine, so as to make the intake more smooth and torque)

1.2 exhaust corrugated hose.

Also known as exhaust hose, it is located in three parts: three-way catalyst, automobile muffler equipment and engine exhaust manifold. The connection mode is flexible connection. Its function is to reduce vibration, buffer, convenient installation, prolong service time, reduce noise, etc.

What is a modified car exhaust that will lose low torque?

1.3 three way catalyst.

After being put into the automobile exhaust pipe, its function is to purify the tail gas. The working principle of three-way catalyst is to convert various harmful gases produced by insufficient combustion, such as CO, HC and NOx, into water, carbon dioxide and nitrogen and discharge them into the air.

1.4 automobile muffler.

Its function is to reduce engine noise. The car silencing device has two pipes of different lengths, and the difference between the two is exactly equal to half of the wavelength of the exhaust sound wave, so that the sound wave will interfere when superimposed, weaken the noise or offset each other. For example, the exhaust pipe of the original car may have a silencer more than the sports exhaust pipe you want to add. When the exhaust is discharged to the silencer, the exhaust of the original car will have a whirling process to buffer the exhaust emission and affect the sound wave. Straight through exhaust is adopted, and the tail gas is directly directed to the exhaust end. That's the difference in the middle. So there is another transformation scheme. Cut off the muffler in the middle of the original car and weld a section of exhaust pipe. However, this is a tested welding technology. If there is a slight air leakage, it is not as good as the exhaust of the original car.

1.5 if the tail throat of exhaust pipe has occurred.

Place the original exhaust tail end. Its function has two aspects: first, it can effectively convert the sound of the tailpipe into a softer one to reduce the noise; Second, it plays a decorative role. For example, change the tail throat from two 03 to four.

2. Design principles of exhaust system transformation.

Reducing the exhaust back pressure of engine exhaust pipe is the main principle of exhaust system transformation. Exhaust back pressure refers to that when the vehicle engine is discharging normally, the force of exhaust pulse is blocked by the pressure from the exhaust pipe, resulting in poor exhaust. To reduce the exhaust back pressure, it is necessary to make the engine work alternately during suction and exhaust as much as possible, which becomes more and more unobstructed and increases the time to enter the exhaust valve. Generally speaking, modification is to change the structure of automobile muffler, increase the flow area of air flow during engine exhaust, and make the exhaust more smooth.

3. Why say low twist?

In the transformation of exhaust system, it generally starts from the middle section. Among them, the key to the improved (drum) to tail (drum) is the pipe type design. There are two forms of pipe type design: "thin" and "short thick". The former means that when the bending shape of the exhaust pipe remains unchanged, only the material of the pipe body is changed. The utility model has the advantages that it can not be discharged quickly in the high-pressure exhaust pipe, and the engine can be obviously improved under the medium and low rotation torque, which is suitable for daily urban driving. The short and thick modification refers to reducing the length of the pipe body and increasing the diameter of the pipe. The advantage of this modification method is that when the engine speed is high, it is dense, the engine horsepower increases greatly, and the exhaust is relatively smooth; The disadvantage of this modification method is that the exhaust pipe is low and the flow rate of exhaust gas is slow at medium and low speed. The mixed gas is forcibly discharged before it is completely burned in the cylinder, resulting in a slightly smaller torque at medium and low speed, that is, the so-called low loss torsion.

4. On the transformation of three-way catalysis.

Three way catalyst is a necessary environmental protection equipment. However, it slows down the flow speed of exhaust gas and produces a certain resistance, which will interfere with the exhaust efficiency, so it needs to be modified. The general replacement method is to directly remove the three-way catalyst or replace the existing pseudo catalytic device to improve the exhaust efficiency. However, these methods can not convert waste gas into waste gas, which will cause the engine emission to be substandard during detection.

5. Linear and back pressure type of exhaust tail throat.

The tail gas transformation involves the middle part of the vehicle, the oil outlet part of the engine, the tail injection section, the silencing part of the catalyst, etc. In general, the modification of exhaust pipe tail throat is divided into back pressure type and direct exhaust type. The modification method should be selected according to the vehicle model and its own characteristics. In the back pressure structure, a large number of artificial diaphragms are contained in the tail throat, which increases the pressure of the cylinder and the combustion ratio of the engine to improve its exhaust pressure. The back pressure is characterized by high engine torque and high exhaust pipe noise. The straight row type has a large inner diameter of the tail throat and a bright and smooth pipe wall, which can make the exhaust smooth. Due to the high number of engine revolutions, the power is relatively large, and the corresponding sound is also relatively large. In addition, the difference between back pressure type and straight row type is that the sound produced by back pressure is generally low and thick. Straight ahead sounds louder and higher.