Have you ever asked yourself what are turbochargers, how do they work and what can you gain with them? When taking a deeper look into modern cars, you may see that most of them come with a turbocharger under the hood. Even cars we associate with big V8 engines by tradition, such as the tarmac-ripping Mustang, now use a small four-cylinder engine equipped with a turbo. Before blaming the entire world for going insane, take a few minutes to think about what made them so popular.
Not so long ago, turbochargers were only common among two vehicle types. One of them were cars and trucks with diesel engines, where turbochargers reduced sluggish acceleration and improved towing capabilities. Others were various performance cars, which used turbos to gain more power and achieve impressive performance figures. By today, these devices have become an industry standard, which is here to stay for a long time. In this article, we will reveal the magic behind turbochargers and bring you up to speed with this technology.
How Do Turbochargers Work?
In theory, turbochargers are simple devices that improve engine performance by using basic laws of physics. You may think of it as a powerful and efficient fan, which pushes an additional amount of air into your engine. With more air in it, the engine can add more fuel to the mixture and generate more power. This is how it all works on paper, but there is much more to it in real life.
Despite different power-train layouts and configurations used in various cars, you will always find a turbocharger in proximity to the engine itself, bolted to the exhaust headers. This is because they use a power of rushing exhaust gases to spin the blades within itself. In normally aspirated engines, this energy is just expelled into the atmosphere as a waste. In turbocharged engines, it is used to generate more horsepower and improve performance in general.
Inside any turbocharger, despite their variations, you will find many components that have an identical function. On one side, there is a housing with a turbine wheel inside. As exhaust gases pass through the housing on their way out of the engine, they spin the turbine wheel. The situation is quite similar on the other side, where a compressor wheel inside its housing rotates to suck in air and compress it before it continues its flow towards the engine. Between these two, there is a shaft that connects both wheels and makes them rotate together. Because of extreme speeds, this shaft spins inside a special bearing on a layer of engine oil.
Feeding air to the engine straight from the turbocharger is not a good idea, as it gets hot during compression. This lowers efficiency and can even cause knocking, which is damaging to the engine. To prevent this, car manufacturers add an intercooler which cools down the compressed air before it enters the engine. It also makes the air more dense, increasing volumetric efficiency. The amount of compressed air that turbocharger creates is called the boost.
What Are the Benefits of Turbocharging?
The most obvious upside with turbochargers is in their ability to increase engine output and make them more powerful. When comparing stock engines, you will see that turbocharged units can produce up to 40% more horsepower than those without it. Although this extra power is great on its own, there is much more to it.
For a start, they will boost low down torque, which makes throttle response faster and improves overall engine performance. It also allows a smaller and lighter engine to have a similar output as a bigger one, making it a suitable replacement. By combining favorable engine characteristics and lower overall weight, it is possible to achieve better driving quality and improved fuel economy.
Still, you need to know that there are several downsides with turbochargers. Because of various parts and assemblies that come with it, like the intercooler or control systems, turbocharged engines are more expensive. Also, added complexity increases the number of potential failure points, which can make turbocharged cars less reliable as ages go by. It also makes maintenance more demanding, as it calls for specialized training and experience.
Can I Add a Turbocharger to Any Engine?
If you ever wanted to upgrade your engine so it would give more power, then adding a turbocharger must have been an option to consider. You can find ready-made kits for many popular engines, which come with everything you need. They should be easy to install and ready for use. Still, are things that simple in real life?
Fitting the turbocharger itself to the exhaust side of your engine is the easy part, as it bolts right to the manifold. With the turbocharger in place, there are still a lot of various hardware parts, like the intercooler and hoses, which must find its place under the hood. Even if you get all of this within the kit, the fitment will require many adaptations and some ingenuity. Also, you must run a set of oil feed hoses from the engine to the turbocharger, as it uses engine oil for cooling and lubrication.
There is also the engine itself, which is designed to work with a certain amount of air and within specific parameters. If you just rush in more air into the stock engine, it will fall apart. Although some engines can withstand small amounts of turbo-boost, you will have to find a way of lowering the compression ratio if aiming at any noticeable power gains. Sometimes you can do this by installing a thicker head-gasket, which is a cheaper solution. However, most engines will require special, lower-compression pistons. This will result in higher costs, as you are doing an engine rebuild.
The final step is deciding on how to control the turbocharger and ensuring that there is enough fuel to match the extra air. One solution is to use a boost controller or some other similar aftermarket device, which will act as a separate unit. If you want a more elegant setup that combines all engine and turbocharger functions in one device, than a standalone ECU that will replace your stock engine computer is the answer. The last step is called mapping, which adjusts the amount of injected fuel for each engine speed and load situation.
How Much Power Can I Gain With a Big Turbocharger?
This brings us to one of the biggest questions regarding turbochargers, and that is the amount of horsepower you can gain with it. The great thing with turbochargers is that it makes engine tuning much easier, which made them popular among car enthusiasts. All you need to do is bring the boost up and adjust the injection system according to that. Although this sounds great, there are some drawbacks and limitations you must have in mind.
By raising the boost and increasing the power output, you are putting additional stress on your engine, which wears it out faster than usual. Not only does this shorten the lifespan of your car, but it also makes it less reliable, as it can break down with no prior warnings. Also, mounting a turbocharger that is too big will cause poor throttle response because of the turbo-lag, which will impact the driving characteristics of your car. For optimal and reliable results, you have to consider all engine components and make sure they are in good balance.
In order to achieve maximum power gains from your turbocharged engine, you need as much boost as possible. The only way to do this is by ensuring that all internal engine parts can withstand extreme pressures and temperatures. For most engines, this means replacing stock pistons, connecting rods and crankshaft with special counterparts, made from forged aluminum. Besides being lightweight, which is useful at high engine speeds, these parts are strong and durable. Combine these upgrades with a bigger turbocharger and high-flow fuel injectors, and can double the output of your engine, adding several hundreds of horsepower under the hood.
When raising engine power in any considerable amount, you must upgrade several other systems that work with it. Additional boost and power will generate huge amounts of heat, so you might need a bigger and more efficient coolant radiator. In addition, your factory installed clutch and other transmission parts might not be up to the task. Also, consider upgrading your brakes and suspension so they can cope with the extra power.
Turbochargers are devices that not only increase both power output and engine characteristics but also help lower the overall weight of the car. This helps ensure better driving dynamics, more comfort, and improved fuel efficiency. When compared to naturally aspirated engines, stock turbocharged units have up to 40% more horsepower and much better throttle response. In addition, turbocharged engines have better tuning options, meaning it is easier to get more power out of them. Still, this is a process that requires knowledge, experience and upgraded engine parts.