（1）General original factory tube
（2）Back pressure tube (the same as the original factory, more environmentally friendly)
Car exhaust pipe
The principle is the same as the original factory, but the sound will be better than the original factory. Most of the original cars use this kind of tube mainly relying on the grating muffler in the tube or the volume change of the tube to generate a pressure that will return to the cylinder. When the engine is ignited, the piston begins to move radially, and the exhaust valve The piston will open before reaching bottom dead center. At this time, the back pressure in the tube will block the exhaust gas from rushing out, allowing the mixture to achieve complete combustion. However, if the back pressure is too strong, the exhaust gas cannot be completely discharged from the cylinder, causing the exhaust gas and the mixture to burn together to reduce the combustion efficiency...Of course, the most direct effect is to affect the horsepower output. Advantages: low noise, good torque at low speeds. Disadvantages: exhaust gas cannot be used at high speeds Discharge quickly, affecting the power output of the engine; volume: low.
（3）Semi-back pressure pipe
This kind of pipe has lower back pressure force, and the exhaust compliance is better than the back pressure pipe. Simply put, it has a moderate back pressure between the return pressure pipe and the straight pipe to obtain the starting torque and exhaust compliance ratio. The back pressure tube is good, of course, the torque of the middle and high speed is also greater than that of the back pressure tube. Advantages: good performance at the beginning and end speed. Disadvantages: noise is too loud; volume: louder.
The acceleration will be better than the back pressure tube, but the biggest disadvantage is that it is very noisy. It will make the "police cup" chase you. The back pressure is extremely low, the exhaust has no resistance, the low-speed torque is poor, and the medium-high speed torque is relatively high Big advantages: smooth exhaust, strong torque at high speed. Disadvantages: low speed and soft power, loud noise (some people say that it is easy to burn the valve and don't know if it is true) Volume: super large...
In fact, the semi-through tube is the same as the semi-back pressure tube, but the exhaust diameter is larger than that of the semi-back pressure tube. Advantages: the starting torque is lower than the semi-back pressure, but the mid-to-high speed torque is greater.
（6）Semi-double valve variable exhaust
A variable exhaust system is connected to the exhaust pipe, and a side pipe is added. When one pipe is fully opened, the other pipe is completely closed. Compared with the single-valve variable exhaust, it has a better sound effect. When the opening is 1/3, the sound effect is more single-valve row. Qi is basically the same. The sound can be switched on and off, and the exhaust can change the size of the sound.
（7）Variable exhaust pipe The exhaust is controlled by valves to achieve the best sound and performance.