Dear experts, there are generally two exhaust pipes in an automobile engine, right? (One on the vacuum booster pump and one on the intake hose) What are their functions?

Now the average car is 4 cylinders! I haven't seen four exhaust pipes either! One or two, according to its displacement, are marked on the engine performance of ordinary cars! One on each side is just for beauty, that's all! However, in the field of modified cars, the number of exhaust pipes can be selected by technicians themselves, and they can also be made into one side, two sides, or two sides, or arranged in the middle of the car body or even on the hood of the car! What's more, technicians make exhaust pipes into various shapes and structures in order to make the sound of exhaust! Generally speaking, the shorter the exhaust pipe, the greater the noise, and the greater the F 1 noise, which is basically the reason! ! The black smoke is gone, but in order to meet the government's emission standards, the automobile company buried some equipment [three-way catalytic converter ~ ~ ~] in the pipeline to filter the tail gas, so it can't be seen! I want to remind you that if all these filters exist and are used normally, and there is black smoke, then there is something wrong with the engine of the car! ! Need overhaul! !