Do-it-yourself direct-flow muffler, is it worth installing it on your car?

Muffler design and functions

People who are not interested in automotive topics believe that there is nothing special about this element. However, this point of view is absolutely wrong. To understand this, you should consider a cross-section of the car muffler design. The exhaust pipe is an integral element of the vehicle and performs a very important function. The main purpose of the device is to suppress the noise that occurs as a result of the combustion of the fuel mixture inside the combustion chamber. Several thousand explosions occur in each individual cylinder in just one minute. A running engine creates a lot of noise. A regular moped without an exhaust pipe sounds unpleasant, while a car makes 10 times more noise.

A properly designed and installed muffler can eliminate this noise almost completely. Thanks to its special design, it perfectly dampens acoustic vibrations with resonator chambers, which are necessarily adjusted to the frequency of a specific motor. There are usually several such chambers, and their design is very diverse and depends on the intricacies of the exhaust pipe design.

something lately I’ve been getting more and more lazy to write entries in the on-board log = (I just made a new release, but I’m too lazy to write...)))

install a turbo supercharger, I made a downpipe with 63 pipes, although the entire exhaust I had before was 51, I wanted something more, that’s why I started with 63 right away so as not to redo it 100 times...

It was decided to cook from ZIL pipes, so we bought the Right and Left intake pipe ZIL 130, they are different in size, so that there would be something to choose bends from =)

Before that, I had 51 outlets with connections just like the standard classics, that is, these flarings where it constantly turns sour, where the pipes spin and sag, disassembling and reassembling it all is the worst thing... so I decided to cook a new system with flanges ! since this is still a 63mm release, you need to steal the clearance from below to a minimum, which means that the flanges are best suited for me with 2 bolts... in order not to have problems with gaskets, so as not to cut them from something yourself, then you need to start from them search)) I went to Google for advice, looked for the simplest solutions, as it turned out these were gaskets from a regular GAZ ZMZ 405 with a catalyst! Once I got to the market, I found them without problems in the first store, the price was 35 UAH, in my opinion not expensive, especially when they sell 3 pieces for 100))

The gasket has a diameter of almost 64mm, it seems, but it still didn’t fit on the pipe, so now I need flanges for them! I didn’t even look for flanges separately, so I had to do it myself) the flanges were made so that they fit onto the pipe from the outside, so that it would be convenient to work with them, since I don’t have any machines, but Stasik22’s dad is a turner, so I had to make the flanges on a lathe machine)) thickness 6mm...

after some minor modifications with a grinder and a drill we have this

The next thing that didn’t suit me about the factory system was the cushions on which everything rests... firstly, they are of no use at all for the muffler, they are frail and there are few of them there, they don’t hold up properly, well, the whole system is attached only near the gearbox and then it’s right on the muffler, the middle not suspended anywhere, this is not correct... I always wanted to install double-sided cushions that work in both tension and compression, in short, like on all NORMAL cars...))

I missed something, I took a photo of them, but I bought 4 pillows at the market that I liked, they are very similar to these (photo from the Internet)

Then I was interested in the exhaust system diagram itself, what to install, where and how in the CORRECT way... of course, for a pipe motor, the best thing is definitely a larger piece of pipe after the snail, shorter and into the atmosphere, but still I don’t have cramps, I need to drive on public roads , and I myself don’t want my head to feel like a tavern after an hour of driving in a car))) I started looking at ready-made exhaust systems from famous manufacturers for turbo cars, systems made to order, I’ve seen enough, I had to wear a bib like my little one!)) ) damn, what cool things people do... and sophisticated systems, and TIG welding everywhere, stainless steel, shooters, dampers that change the geometry of the system, homemade attachments that are cooler than market ones... in short, one frustration... ((( I started thinking about how to make a system with a damper and a variable loudness, but when you sit at the computer and dream and when you climb under the car, you look at how much space there is in the Zhiguli and what a 63mm pipe under the car is, you understand that you need to forget about all this and do as usual...(((the next thing was the system components, everything systems not made with feet had a resonator somewhere in the middle of the highway (sometimes a little closer to the engine) and a terminal muffler... well, that’s what I thought, if it’s not a large volume, then the resonator can fit between the elastic coupling and the outboard one in order to press it closer to the cardan, so that it wouldn’t hang low, then I went again and looked at it all with my own eyes, took a piece of 63 pipe, applied it and realized that this was nonsense... the car is not so high that the ground clearance would spread out, there is no place to just put it there...

since everything is going so well that nothing turns out the way you want, then there is only one option left - a completely straight can and as large a volume as possible to drown out the hum, so that it doesn’t scream loudly, otherwise you’ll drive along the highway later and won’t want anything else...) especially since we increase the diameter of the pipe, and the larger the diameter, the louder the system works, which means we will make the maximum muffler!)

What is a direct-flow exhaust system

To understand why to install a direct-flow muffler, it is important to know how the car’s exhaust system works.

Main goals:

1. Filling the cylinders with a prepared fuel-air mixture, and in diesel cars - forming the fuel mixture in the combustion chamber;
2. Ensuring the removal of spent fuel gases from the engine and passenger compartment outside the vehicle;
3. Reducing the emission of toxic gases and harmful substances into the atmosphere thanks to the built-in catalytic converter;
4. Reducing noise levels in the cabin and surrounding area.

The operating principle of the exhaust system is partly based on the law of inertia.

Thanks to the action of this law, a vacuum zone is formed behind the exhaust valve into which gases rush, and their place is immediately taken by a fresh portion of the fuel mixture.

This happens due to the fact that the phases of fuel intake and exhaust gases overlap each other, as is provided for in the design of modern engines.

After the exhaust valves are closed, next to the high-pressure zone formed as a result of exhaust gases escaping under pressure, another low-pressure zone is formed in the manifold, which moves along the exhaust pipe at the speed of sound.

Entering the muffler, the vacuum zone encounters resistance in the form of partitions, is reflected and goes in the opposite direction to the valves.

The ideal case is when this zone approaches the motor at the moment the valves open, but this depends on the frequency of the engine and the distance to the obstacle.

And since in modern cars such a distance is large, the vacuum zone from one cylinder, as a result, at the moment the valve opens, ends up in another, and not in the one from which it left.

Thanks to the design of the “spider” (exhaust manifold), where pipes of the same length are provided, the effect of vibration damping occurs, since the vacuum zones go from 4 pipes into one, where resistance is created at the junction of the latter, and they also partially dampen each other.

But the muffler plays a leading role in noise reduction, because the exhaust manifold and other elements are unable to greatly reduce noise.

But on many sports cars such a device may not be found; the role of a muffler there is played by a special turbine, which smoothes out vibrations and reduces the force of the exhaust by grinding the outgoing gas flow.

Why is a homemade element better than a factory one?

Due to the large number of fakes, it is very difficult to find a truly high-quality spare part today. And if such a part is found, the price for it will be simply exorbitant. Moreover, most of the complaints concern the elements of the exhaust systems. The muffler rusts and burns out very quickly. Its service life does not exceed 1-2 years. It doesn’t matter how intensively you use your car. It burns out not from mileage, but from time. Even if the car is driven once a week, this will not add life to the muffler. It will still have to be changed in a year or two.

After this time, car enthusiasts have a question about the need to replace or repair this part. If you repair the muffler yourself or make it from scratch, you can be sure that it will last much longer. After all, we will not skimp on important materials. Also, by making a muffler with your own hands, you can add your own configuration to the exhaust system. For example, make a forward flow to increase engine power. However, driving long distances with such a “can” will be uncomfortable. Therefore, you can remake the system in a different way by adding an additional resonator to it. This way the machine will run much quieter.

Principle of operation

Before you begin repairing a car muffler or assembling it yourself, you need to understand the basic principles of its operation. If you look at the device in section, you can see many metal or ceramic partitions, heat-resistant wool, and the presence of perforated pipes. The presence of these elements in the muffler design slows down the speed of gas flows. When doing DIY repairs, it is important to replace worn-out elements with high-quality analogues.

In turn, their reduction allows you to smooth out the operation of the motor, taking into account each stroke.

There are no standards for the production of the exhaust system and its individual elements, so mufflers from different car manufacturers can differ significantly from each other.

If you decide to upgrade individual elements of the exhaust gas removal system with your own hands, then you need to take into account some nuances:

• powerful car engines must have a resonator of sufficiently large volume, which will provide the necessary level of exhaust smoothing;
• the number of partitions inside the chambers that smooth out the unevenness of the volume of discharged flows.

Material and manufacturing method

Before you make a muffler with your own hands, you need to decide on the budget and the option for reworking the exhaust system. There are several tuning methods:

• Modification of a new factory muffler.
• Making your own. By the way, you can make a muffler with your own hands using both stainless steel and ordinary steel.

Experts do not recommend using old mufflers or other parts of the exhaust system that have already been used. In this case, even if they look good (after all, they can be repainted before selling), the inside will be covered with corrosion or even burnt out. Remember that with each engine start, the metal in the system heats up and changes its properties. It’s easy to guess what condition a muffler will be in if it’s been used for about 2-3 years on a car. Therefore, do not fall for the tricks of “lightly used” sellers and do not buy a used muffler. Best of all, make it yourself.

A less expensive solution from a financial point of view would be tuning the standard muffler. Making a part with your own hands from stainless steel is a very reliable, but expensive option. However, such an element will be more durable and will not burn out at the most inopportune moment.

Advantages

A car enthusiast is thinking about replacing a conventional muffler with a homemade direct-flow version due to the following reasons:

1. Replacing the muffler with a supply version will help increase the car's power by several horsepower. Of course, this improvement can only be felt, as they say, by seeing the data after measurement on paper. After all, it’s almost impossible to really feel the difference of a couple of horsepower. But the feeling that the car has become a little more powerful is pushing car enthusiasts all over the world to replace the conventional factory muffler with a direct-flow muffler.
2. Giving the engine a noble sound, which is characteristic of powerful versions of machine power units. It is also worth noting that using various design options you can choose the appropriate sound timbre. However, whatever one may say, if you put next to a car with a powerful engine and a simple, direct-flow muffler, the sound from it will be better, mesmerizing and penetrating deep into the body, than from a conventional installed engine. But the opportunity to do something like this pleases many car enthusiasts.
3. The desire to remake the car for yourself. This desire is not caused by the desire to achieve any result, but is perceived as a system for improving the car.

A straight-through muffler will help increase the car's power.

Pay attention to weight

Due to the fact that the water pipe weighs an order of magnitude more than the one that comes with the part from the factory, you will have to strengthen the fastenings. In addition, you should insert the flexible corrugation into place that goes after the exhaust manifold.

Thanks to such changes, the noise level will be significantly reduced, and the service life of the part will be more than 2 years. By the way, the heavier the pipe, the less vibration it will emit.

Adviсe

In order to reduce the noise of a homemade muffler, it is recommended to fill its body with some material such as glass wool. It is also recommended to make a condensate drain hole at the bottom of the muffler. Thus, it will not rust prematurely and make extraneous noise.

If this is a muffler made with your own hands from stainless steel, it is important to think through its design. Make it partially collapsible. This way you will periodically clean the pipe cavities from dirt and change the filler if necessary. Thanks to the collapsible design, the service life of the part will increase several times. Do-it-yourself installation and replacement of the muffler is done in standard places. The main thing is to strengthen them, since the weight of the structure increases slightly.

The role of mufflers in cars

The exhaust pipe system, despite the apparent simplicity of its purpose, performs several important functions, namely:

• a significant reduction in the intensity of sound phenomena occurring during fuel combustion;
• reducing the temperature of gases that initially have very high thermal indices;
• reduction of exhaust gas toxicity.

That is, a muffler is needed not only to make the car quieter, although, in fact, this is its main purpose.

A homemade muffler can be made from scrap materials.

Painting issue

Is it worth painting the muffler? There is no clear answer to this question. Most car enthusiasts say that the paint for it should be fire-resistant. Otherwise, it will simply burn. The ideal solution would be to make a muffler made of stainless steel. You can see an example in the photo below.

Using stainless steel will close the issue of painting once and for all. Well, you can paint the muffler on the carbine with your own hands with matte black paint. The main thing is that it is resistant to high temperatures.

How to repair a muffler with your own hands without welding?

Now there is a new method for restoring the performance of exhaust system parts using a universal composite polymer (various sealants). Thanks to their special composition, they harden quickly and are not subject to external negative influences, including high temperature changes, which is very important for the exhaust system. In car markets you can find two types of sealants, thanks to which you can repair the muffler yourself without welding:

In combination with high-quality reinforcing components, these types of sealants will create a reliable “patch” on the burnt-out section of the muffler. Car enthusiasts note the effectiveness of plastic elements. It is these sealants that are characterized by high adhesion to metal, even if there is rust on it.

About direct flow or PG

A direct-flow muffler (PG) is an improved alternative to a stock exhaust, which is not capable of ensuring a quick and timely release of gases from the engine system (ICE). The standard exhaust system especially suffers (chokes) after installing a sports camshaft or after boring the cylinder head cylinders (in other words, on a forced engine).

A straight-through muffler is designed to improve the exhaust system

The GHG is designed to modernize the exhaust system, which increases gas emissions. In addition, a correctly installed PG will provide an increase in internal combustion engine power by 10–15 hp. However, you need to be prepared for drastic changes: everything will need to be replaced, from the catalyst to the tip.

How to use?

Do-it-yourself cold welding of a muffler is done as follows. First, the surface goes through a preparation procedure. The area should be cleaned with sandpaper. After this, the surface is degreased using white spirit, gasoline or another solvent. Next, you should prepare the adhesive composition. Cut off the required amount of sealant and knead it. In the case of using liquid analogues, mix them thoroughly. Next, apply glue to the damaged area of ​​the muffler and level the mixture.

Please note that the composition hardens within a few minutes, so all work with the sealant must be done very quickly.

Finally, you need to wait until the mixture dries completely. Depending on the brand of the manufacturer, this takes from 1 hour to a day.

Types of car mufflers

Modern mufflers are divided into three types: dissipative, reactive and combined.

In turn, the above types are divided into two types: direct-flow and labyrinth.

They belong to the type of direct-flow mufflers and have a simple design.

1. Housings;
2. Perforated pipe;
3. Inlet and outlet pipes;
4. Special heat-resistant sound-absorbing filler;
5. Steel mesh;
6. All this is connected by all-welded joints.

How else can you reduce exhaust system noise?

To do this, you can install an additional muffler resonator. You can make it from scratch, like the muffler itself, or you can make it again from a fire extinguisher. However, the material of this part is not particularly designed for high temperatures. But, as practice shows, such resonators are quite effective in operation.

The most important thing when making an additional resonator is to place the tubes correctly. They must be offset relative to each other (everything is similar to making a muffler). To swirl the exhaust gases, holes are made in the pipe. Thus, the gas pressure level decreases and they do not create much noise at the outlet. As you can see, making a resonator for a muffler with your own hands is not so difficult.

The weight of the newly manufactured element should also be taken into account. If it is heavier than the standard one, you will have to strengthen the fastenings on the bottom, otherwise the part may come off right on the move. It is not necessary to fill the inside of the resonator, nor is it necessary to install partitions.

So, we found out how to make a muffler with our own hands.

Types of noise-absorbing elements

Silencers in cars can be active, which is a fairly simple device, or reactive. In the first case, vibration-resistant materials that can withstand high temperatures are used for their production. Active devices are the most popular because they are easy to use. Their significant disadvantage is their rapid contamination. Silencer reactive devices consist of complex elements of resonator chambers.

As for the rear noise-absorbing chamber of the car, its structure contains many compartments that contain a special filler. It is necessary to reduce the sound of exhaust gases when the car engine is running. Modern car mufflers can use several technologies for absorbing background noise and purifying emitted gases at the same time. They can contain many different materials that provide maximum reduction in the sound of exhaust gas flows, their toxicity level and temperature.