(1) Increase air flow and reduce intake resistance. Replacing the high-flow air filter can reduce the intake resistance of the engine and improve the intake volume and volumetric efficiency per unit time when the engine is running. If you want to achieve better results, you can also modify the whole air filter into an exposed filter, commonly known as "mushroom head", to further reduce the intake resistance and increase the intake volume of the engine.

(2) Change the shape of the air inlet to increase the airflow speed. The improvement of inlet can be carried out from two aspects: shape and material. Change the shape of the intake port, first, to realize the accumulation of intake pressure, so as to meet the need of sudden full opening of the throttle during rapid acceleration; The second is to increase the intake air flow. In principle, the requirements for changing the inlet material are non-heat absorption and light weight. At present, carbon fiber is the most commonly used material for automobile modification. Its advantage is that it does not absorb heat, but its disadvantage is that it is expensive. Usually, racing cars will improve the shape and material of the air intake at the same time, transfer the air filter together or even simply remove it, and extend the air intake to the outside of the car, so as to increase the intake pressure with the increase of vehicle speed, thereby increasing the intake air volume and maximizing the vehicle power.

(3) Secondary air intake is adopted to improve the inflation efficiency. Secondary air intake is to use the vacuum pressure difference of the intake manifold to connect another air intake device from the PCV (Crankcase Forced Ventilation) pipeline of the engine, in addition to the air inhaled by the air cleaner, and introduce an appropriate amount of fresh air to achieve the purpose of improving volumetric efficiency. The power boost function of secondary air intake is mainly in the low-speed stage with small throttle opening, because in the high-speed stage with full throttle opening, when a large amount of air enters to reduce the vacuum degree, the amount of air that can be introduced by secondary air intake device becomes relatively insignificant.