TURBO 101 - How it WORKS and what's INSIDE - BOOST SCHOOL #2

What about the engine bosses? Welcome to another episode of Boost School, the YouTube equivalent of a college course on forced induction, made possible by people narrower than the good guys at a e m. In today's episode of Boost School, we'll take a detailed look at a

turbo

charger. We're going to start small and simple by finding out how the

turbo

works

and

what

's

what

in a turbocharger and then we're going to take the turbo, we're going to take it apart and we're going to take a detailed analysis. look at its internal parts and we will explain and cover the key concepts related to the turbocharger, so sit back, relax and together let's delve into the turbo, so here we have our turbo.

The most basic observation we can make about a turbocharger is that it can be divided into the cold and hot side. The hot side houses the turbine wheel and the cold side houses the compressor wheel. All turbos are bolted to the engine on its hot side. This part of the turbo here is the flange and it is what you bolt onto the exhaust manifold of your engine, this particular turbo uses a t25 flange, but turbos can use many different types of flanges or they can use a clamping system. V-belt, so that when the engine is running, it creates exhaust gases;

Otherwise, these exhaust gases would be wasted. But in a turbocharged engine these hot, fast-moving gases are used to drive the turbine wheel. I'm going to use my air gun to simulate the exhaust gases so you can see how they spin the turbine wheel as they enter the turbine housing on the other one. turbo side the cold side we have the compressor wheel the compressor wheel has a fixed connection to the turbine wheel through a common shaft, so when the turbine wheel rotates it also rotates the compressor wheel the shape of the compressor wheel is designed to suck air.

The turbocharger is called compressor wheel because in addition to sucking air into the compressor wheel, it also plays an important role in compressing the air, after which the air is sent to through the compressor housing to the engine intake manifold and from there to the combustion chamber. Air is what helps turbocharged engines make more power at atmospheric pressure, which is the normal air pressure we all live in. There is a certain amount of air in a certain amount of volume. So, for example, let's say your engine has four cylinders and two liters of displacement. This means that one of its cylinders has 500 cc of displacement or volume.

Now for the sake of simplicity let's imagine that at normal atmospheric pressure there are a million molecules of air in that single cylinder, an engine generates energy by burning air and fuel to create an explosion that drives the piston, the more air and fuel it has in your cylinders, the more power you will be able to generate, so how can you generate more power? Simply increase the volume of your cylinders or the number of cylinders so you can have more air. and fuel in them and they create bigger explosions and ultimately make more power, so instead of a two-liter four-cylinder you get a three-liter or maybe a six-cylinder and voila, you're making more power.

Yes, the new engine is heavier and bigger, but who cares? But what if there was another way to make more power without increasing the size and weight of your engine? Thanks to the turbo, as we said, the turbocharger compresses the air, which means it actually introduces more air into the same volume of the cylinder, so let's go back to our 500 cc cylinder that has 1 million air molecules at atmospheric pressure. Now let's add a turbo to the equation. The turbocharger compresses the air, so the molecules are now closer together, meaning there is more in the same amount of space.

So instead of 1 million molecules, the cylinder now has 1.5 million air molecules and if you increase the amount of fuel given to that engine, you are creating more powerful explosions with the same 500 cc volume of the engine. cylinder, the engine size has not increased. but power surely has, as you can see, adding a turbocharger or increasing the pressure of an existing turbocharger increases the amount of air entering the engine, but engines need a certain air-fuel ratio to generate power, which means it is It is necessary to increase the amount of fuel when the amount of air increases and when it comes to increasing the amount of fuel, AEMS has you covered with some top-notch fuel pumps and fuel pressure regulators to make sure your engine reaches its full potential. . links to aem fuel pumps and other amazing products are in the video description and in the comment pinned for the turbo to compress the air, it increases the air pressure and this leads to the natural question of how do we control the amount of pressure that generates a turbo, how do we make sure that the The turbo doesn't compress the air too little or too much because without control, the turbo would, in theory, just keep pressurizing the air until the excessive pressure would cause something to fail.

Enter the discharge valve. This is what controls the amount of pressure created by the turbo. The wastegate system consists of the wastegate itself and a wastegate actuator. The actuator is connected to the compressor housing through this hose. This means that any pressure created by the compressor is also exerted on the actuator through the hose inside the actuator. We can find a diaphragm and a spring, once the pressure is strong enough to overcome the resistance of the spring, the actuator will move from its rest position and because it is physically connected to the wastegate, it will open it again .

Let me demonstrate how to use my air gun to simulate the pressure generated by the compressor. wheel so you can see how the pressure opens the wastegate once the wastegate opens it allows the exhaust gases to escape before they reach the turbine wheel. This means that the turbo slows down and stops generating as much pressure. The system you just saw is internal. Wastegate means it is a wastegate that is part of the turbo itself, but turbocharged engines can also have external wastegates that are separate from the turbo. I'll cover the differences between these two in one of my future videos so we continue to say how the compressor wheel increases air pressure, but how does it actually do it?

To properly understand how the turbo generates pressure, we must disassemble it to remove the wastegate actuator, compressor housing and finally the turbine housing until we are left with nothing but the turbo core or cartridge. So this part of the turbo housing and this cartridge plate play a key role in pressurizing the air. When these two parts come together, they create the diffuser. The diffuser converts fast-moving, turbulent, low-pressure air leaving the compressor wheel into slow-moving air. High pressure air To understand how it does this, we have to take a look at the ideal gas law. Now I will not bother you with any formula and the only thing you have to know about the ideal gas law is that the pressure and volume of the gas are inversely proportional, this means that as the volume decreases, the pressure increases and vice versa and As you can see, the shape of the diffuser incorporates a dramatic decrease in volume, the compressor wheel throws and fills the air into the narrow space and this can decelerates and pressurizes it.

The air then travels through the volute into the engine but there is something else we can apply from the ideal gas saw to the turbo, as we said pressure and volume are inversely proportional as one decreases the other increases , but pressure and temperature, on the other hand, are inversely proportional. Directly proportional as the pressure increases so does the temperature and this makes sense as the air molecules are compressed closer together, they begin to make more contact generating more friction and therefore more heat. This is why turbos not only pressurize the air, but also heat it and This is why turbocharged setups very often encode an intermediate core, the intercooler cools the air again to prevent the mixture of air and fuel in the combustion chamber is pre-ignited because it is too hot.

Now let's take a look at the turbo core as you can see what it consists of. of the turbine and compressor wheels and the center section the center section houses the shaft and some holes this particular turbo is oil and water cooled it has inlets and outlets for both the engine oil and coolant some turbos are only oil cooled while others, although not as common, are neither water nor oil cooled. Water cooling is often beneficial because it helps keep engine oil temperature under control. The turbo generates extreme amounts of heat which can cause spikes in oil temperature and this can shorten both the life of the turbo and the engine coolant it circulates.

The turbo helps keep the oil temperature stable. The compressor wheel in almost all automobile turbochargers is radial, this means that it sucks in air in one direction but compresses it in another, in most cases, with a displacement of 90 degrees from the direction of the air inlet, turbochargers can also have axial compressor wheels, but they are very rare in automobiles and are more common in trucks and industrial machinery. The jet engine is also an example of an axial air compressor because it compresses air in the same direction of its movement within the turbo core. You will also find some bearings.

A turbocharger has two types of bearings, one that controls the radial movement of the shaft and others that control the axial movement of the shaft. The bearings that control radial motion can be plain bearings or ball bearings. Ball bearings can be beneficial. in the sense that they can offer lower friction and faster turbo start times, however, sleeve bearings are also suitable for a wide range of applications, bearings that control the axial movement of the shaft are called trust bearings, the turbo can actually be seen as a simplified version of a piston engine because the turbo shaft, like the crankshaft, has two types of bearings, you will notice that I have not disassembled the turbocharger further and that I have not removed the compressor and cartridge turbine wheels.

In fact, I have a There is a very good reason for these turbochargers to spin at extremely high rpm, often above 100,000 rpm and some turbos even reach speeds of 250,000 rpm. This is why it is absolutely essential to have the turbocharger balanced properly. A turbo is dynamically balanced by turning it. On a machine at operating rpm, the machine determines where weight should be removed to achieve the perfect balance. This is very similar to the dynamic balancing process of a crankshaft and you can see dimples in the crankshaft where weight has been removed to achieve the perfect turbo balance.

It is actually balanced with the core fully assembled and this means that removing the compressor or turbo wheels will distort the balance and although you can mark the wheels and retaining nuts to try to return them to the same position, this is often physically impossible, You might get it close, but you'll never put it back in exactly the same position where it was, which means you're potentially reducing the life of the turbo and of course that's something no one wants, so there you have it. , this video was basically turbo 101 and into our future. In the videos we will continue to delve deeper into the turbo with a more detailed analysis of all its components, including different compressor wheel designs, wastegate types, bearings and much more.

I hope you enjoyed this video and found it useful and informative as always, thank you very much for watching. And I'll see you soon with more fun and useful things on the d4a channel.