Air filter is a device for purifying air. It consists of a shell and a filter element, and the filter element is arranged in the shell. There are various foreign matters in the atmosphere, such as dust, sand, etc., which will accelerate the wear of the engine, thus reducing the service life of the engine. The advantage tire will carry fly Rock, once it enters the engine, it will cause serious damage to the engine. The air filter can prevent this situation. In order to increase the intake volume, the air filter housing is generally relatively large. Many racing cars even design part of the frame as the air filter housing to increase its volume. When the engine is running, the intake air is intermittent, which causes the air vibration in the air cleaner housing. If the air pressure fluctuation is too large, the intake air of the engine will be affected. In addition, the intake noise plus-sized. In order to suppress the intake noise may be plus-sized of the air cleaner housing volume and, in some cases, also arranged therein the separator so as to reduce the resonance. Air filter is a device for purifying the air. It is composed of a shell and a filter element, and the filter element is arranged in the shell. There are various foreign matters in the atmosphere, such as dust, sand, etc., which will accelerate the wear and tear of the engine thus reducing the service life of the engine. The advantage tire will carry the flying stone, once enters the engine, can cause the engine serious damage. Air filters prevent this from happening. In order to increase the air intake, the air filter shell is generally larger many racing cars even frame part of the design of the air filter shell, in order to improve its volume. When the engine is running, the air intake is intermittent, which causes the air vibration in the air filter shell. If the air pressure fluctuation is too large the air inlet of the engine will be affected. In addition, at this time will also increase the intake noise. In order to restrain the intake noise, the volume of the air filter shell can be increased, and some spacers are arranged to reduce the resonance.