The exhaust system of the car is very important. Its main purpose is cylinder ventilation. The exhaust gases in the exhaust stroke fall into the exhaust manifold, and then go to the exhaust pipe. Further on the path of “smoke” a couple of resonators meet, and such a “journey” ends with an exit to the atmosphere through a silencer. Let's pay a little attention to its design. In fact, a silencer is a can with various partitions inside. They form a kind of labyrinth, passing through which the gases are cooled, lose speed and somewhat decrease in volume.
Often manufacturers do not count the exhaust system for maximum performance, then the tuners have to make some parts, say, a muffler, with their own hands. What are the advantages of handicraft production over factory? Let's look at them. The very first reason you should make a silencer with your own hands is an increase in its volume. In this case, the gas pressure at the outlet will drop significantly, which will entail a marked decrease in the noise level of the car as a whole. In addition, pressure will drop in the system. Then the exhaust gases are easier to exit the cylinders, therefore, the performance of the power unit is slightly increased.
The second reason you should make a silencer with your own hands is the material of manufacture. As a rule, the main reason for the failure of the exhaust system is its burnout, because the operating temperatures are very high. Conclusion: you need to choose a material of greater thickness.
It can be a pipe or sheet metal. Naturally, it is worth remembering about the weight of the product. Such a homemade silencer can last much longer than a regular one. In addition, you can change the geometry of the partitions inside, which will also positively affect the performance of the entire system and the noise of the exhaust.
There are many instructions on how to make a silencer. Each of them is almost universal. This is not surprising, because a muffler with your own hands can be made for one model and brand, and it will fit even a dozen of them. Here, in principle, the distinctions relate only to the working volume of the engine, since a too small silencer simply will not be able to cope with the volumes of gases passing through it.
In addition, the engine will be too noisy. From the above it follows that there are quite a few reasons to make a muffler with your own hands. But do not think that this is a win-win option, thanks to which you will never know the problems with the exhaust system again, and the engine will immediately become more responsive several times and will not make a sound. Everything has its drawbacks.
For example, inspection. With such a silencer, certification problems may arise. If the noise standards are not exceeded, then everything will be in order. The design does not affect the toxicity of the exhaust. Particular attention should be paid to the mounts: they must be flexible, and also the “backside" should not touch the bottom of the car. Also, do not forget about fire safety, for which a sheet of asbestos laid between the muffler and the bottom will be enough.