What is a turbo engine in cars, and how does it work?

Published on 18 Nov, 2021, 10:50 AM IST
Updated on 7 Jun, 2022, 7:25 AM IST

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Cars are no longer just a mode of transportation. They are stylish, powerful and offer an enjoyable driving experience. Modern cars come with powerful engines, and turbo engines are one of the main reasons for the leap in performance over the years. So, what is a turbo engine in cars, and how does it work? Read ahead to know all the details about turbocharged car engines.

What is a turbo engine?

A turbo engine in cars is an internal combustion engine used in automobiles fitted with a turbocharger device. Hence, they are also known as turbocharged engines. Turbochargers are mainly used to improve the performance and efficiency of an engine. In the following sections, we will explain how a turbo engine works.

What is a Turbo Engine in Cars

How does a turbo engine work in a car?

A turbo engine in a car works like any other internal combustion engine. The only difference is extra compressed air is fed through the turbocharger to engine cylinders. This phenomenon is also called forced induction of air into the combustion chamber. 

It may sound a bit too complicated for now. But when you understand the turbocharger working principle, you will have a clear picture of how a turbo engine works.

The below points explain the working mechanism of a turbocharger that is fitted to a car’s engine.

  • A turbo comprises two major components: turbine wheel and compressor wheel.

  • The turbine and compressor wheel are held together by a shaft.

  • The components are enclosed in a snail-shaped housing, with an inlet and exhaust port.

  • The exhaust gases produced by the engine enter through the turbo’s inlet port at high pressure.

  • The high-pressure air spins the turbine, and in turn, it spins the compressor wheel.

  • When the compressor wheel spins, it draws a vast amount of air that is compressed and pushed out of the exhaust port.

  • The compressed air is fed into the cylinders through a pipe and via an intercooler.

  • Due to the hot exhaust gases, the air will be hot. An intercooler cools the air before it reaches the cylinders.

  • Generally, a turbo has an oil cooling system since it runs at very high speeds.

  • Some turbo systems also have a wastegate valve to divert excessive gases from the turbocharger if the engine produces too much exhaust gases.

  • The wastegate valve prevents any damage to the turbine by controlling the rotational speed.

Apart from the turbocharger’s working mechanism, the rest of the engine works as a regular internal combustion engine. The only difference of a turbo engine is that it gets additional compressed air from the turbocharger to produce more power and enhanced efficiency.

Turbo engine advantages and disadvantages

Refer to the table below to know some of the advantages and disadvantages of turbo engines in cars.

Parameters Advantages of turbo engines Disadvantages of turbo engines
Usage and construction A turbocharger can be used in both petrol and diesel engines. Turbo engines comprise complex parts. If they fail or develop faults, it can impact other engine components.
Power and cost A smaller turbo engine generates the same amount of power as a larger naturally aspirated (NA) engine. Turbochargers are expensive, and the same applies to repair costs. Replacing a turbo can be a costly affair.
Performance A turbo engine is lighter than a NA (Naturally Aspirated) engine due to the smaller engine capacity. You may experience turbo lag, which is a common problem in a turbo engine. It is a slight delay in the delivery of power after you press the accelerator pedal.
Fuel economy A turbo engine may also deliver better fuel economy due to its compact nature. Turbo engines are efficient, but one should be careful with the throttle to extract better fuel economy. If driven over aggressively, it may return poor fuel efficiency.
Eco-friendliness and initial cost Turbo engines are more eco-friendly than NA engines as they burn fuel more cleanly and produce less pollution. Turbo engines are more expensive than NA engines.
Torque and reliability Generally, turbo engines produce more torque in the lower rev range. It results in excellent initial acceleration. A turbo engine is less reliable than a NA engine. Since a turbocharger works under a lot of stress, it is prone to breakdowns.
Refinement and exhaust note Turbo engines are refined as a result of clean air entering the cylinders. The engine produces less noise compared to a naturally aspirated engine. It may be subjective, but turbo engines do not produce a throaty exhaust note. Due to the smaller engine capacity, they do not sound the best.

Difference between turbo engine and normal engine

Now, you know how a turbo engine in a car works and their pros and cons. The next question on your mind would be how is a turbocharged engine different from a normal or naturally aspirated engine. The below table answers your questions related to turbo engine vs normal engine.

Parameters Turbo engines Normal engines (Naturally Aspirated)
Working principle Forced induction of high pressure air. The air fed to the cylinders depends on the atmospheric air pressure.
Power Produces more power than larger NA engines. Produces the same/less power than smaller turbo engines.
Torque Produces more torque. Torque figures are lesser than a turbo engine.
Fuel efficiency May deliver higher fuel efficiency due to smaller engine capacity. Fuel efficiency is compromised due to larger engine capacity.
Reliability Not as reliable as a normal engine due to complex mechanical parts. Reliable than a turbo engine.
Repair costs High Lower than turbo engine
Initial cost High Lower than turbo engine
Maintenance Requires regular maintenance of turbocharger. No additional maintenance required.

Turbocharger vs supercharger: which Is better?

Here are some major differences between a turbocharger and a supercharger used in an internal combustion engine.

Parameters Turbocharger Supercharger
Working principle Uses velocity and heat energy of the exhaust gases to spin the turbine wheel. The engine mechanically drives a supercharger via a belt driven by the crankshaft.
Air induction Forced induction of compressed air Forced induction of compressed air
Boost lag There is a turbo lag or delay in response while applying the throttle aggressively. There is no boost lag or delay in power delivery.
Fuel efficiency Enhances the fuel efficiency. Hampers the fuel efficiency as it uses engine power to spin the compressor.

So, now the question is which is better, turbocharger or supercharger? From a practical perspective, turbochargers are the way to go. They deliver a perfect blend of power and fuel efficiency, which most car buyers are looking for. Hence, car manufacturers use turbochargers in most modern cars.

On the other hand, superchargers are for outright power that comes at the cost of low fuel efficiency. They are best suited for high-end sports cars with high capacity engines. In the world of performance/sports cars, fuel efficiency is thrown out of the window. Hence, superchargers find a perfect home under the bonnet of such vehicles.

What is a turbo-petrol engine?

A turbo-petrol engine is nothing but a petrol internal combustion engine that is fitted with a turbocharger. One of the main highlights of such engines is they are powerful and efficient than larger capacity naturally aspirated petrol engines.

The turbocharger can draw more air and compress it before it reaches the cylinders. It makes a smaller petrol engine behave like a high capacity engine due to the more powerful combustion. Hence, a smaller turbo-petrol engine can produce the same/more power than a high capacity NA petrol engine.

What is a turbocharged diesel engine?

A turbocharged diesel or turbo-diesel is an internal combustion engine with a turbocharger assisting in providing compressed air for better combustion. The more efficient the combustion of fuel, the more efficient and powerful the engine.

Hence, turbo-diesel engines produce more power and are also fuel-efficient at the same time. Turbochargers also help in generating a superior torque curve as compared to a naturally aspirated diesel engine.

Turbo engine oil and its usage

Engine oil in a turbocharged engine is also used to lubricate and cool the turbo. Yes, a turbo operates at very high RPMs and high temperatures. Without lubrication, the turbo could break down due to the high temperature and forces. Hence, the oil is fed to the turbocharger, and it acts as a lubricant and coolant.

Lack of oil or any issues with oil supply lines can cause irreparable damage to the turbo. Similarly, any impurities in the engine oil can also damage the turbocharger components. So, one has to pay attention to the engine oil level and the quality of the oil to keep the engine and turbo in perfect condition.

Also, read: What is RPM in cars?

What is a twin-turbo engine, and how is it different?

A twin-turbo engine is a car engine with two turbochargers. The basic working of a turbocharger remains the same except that two of them are working simultaneously to deliver compressed air into the combustion chamber. Twin-turbo engines produce almost double the power of naturally aspirated engines. You can find such setups in high performance or modified cars.

The below points explains more details about a twin-turbo setup in an engine.

  • There are mainly two types of twin-turbocharged engines based on the configuration: sequential and parallel twin-turbo engines.

  • In a sequential setup, there are two turbochargers of different sizes.

  • The smaller turbo is responsible for providing a boost at lower RPMs, while the larger turbo works at higher RPMs.

  • In a sequential twin-turbo engine, one can experience more power lower down the rev range.

  • In a parallel twin-turbo engine, both the turbos are of the same size and operate simultaneously.

  • Both the turbos perform equally by splitting the cylinders. For example, in a V6 engine, each turbocharger is responsible for three cylinders.

  • In a parallel twin-turbo engine, there is considerably less turbo lag due to two turbos working simultaneously.

What is turbo lag, and how do you get rid of it?

Turbo lag is a slight delay in response after you press the accelerator pedal. It happens because the engine is not producing enough exhaust gas to spin the turbo's turbine wheel fast enough.

You experience turbo lag only when you drive aggressively or suddenly accelerate from a closed throttle position. So, turbo lag is not a big issue in a modern car, at least for everyday drivers.

Car manufacturers eliminate turbo lag by fitting two turbocharges to the engine. That's the reason why twin-turbo engines are generally free from turbo lag. Another way to get rid of turbo lag is by using a supercharger. Since the engine power drives a supercharger, there is no lag in boost.

Tips to make turbo cars more efficient

A turbocharged engine is not all about power. Fuel efficiency also matters. So, here are a few tips to enhance the fuel efficiency of a turbo car.

  • Always maintain a low and constant speed while driving your turbocharged car. Drive at a comfortable cruising speed and constantly maintain that speed. An engine running at a constant and optimum RPM returns better fuel economy.

  • Shift the gears early to a higher gear. Turbo engines produce more torque lower down the rev range. Hence, the more the RPM at lower gears, the more the fuel consumption. So, shifting to a higher gear as quickly as possible will help improve fuel efficiency.

  • Learn to lift and coast while driving your turbo car. It’s nothing but getting off the throttle and allowing the vehicle to roll. The engine braking will slow down the car. You can apply this technique while stopping at a traffic light. But make sure that you anticipate the traffic before lifting and coasting.

  • You may use high-quality fuel or premium fuel in your turbocharged car to extract the best fuel economy. High-quality fuel results in efficient combustion, and hence the engine may return better mileage.

  • Maintain the correct tyre pressure as recommended by the car manufacturer. Tyre pressure is often overlooked, but it impacts fuel efficiency. So ensure that you maintain the optimum tyre pressure in your car.

What should you not do with a turbo engine?

Turbo engines are powerful and efficient. However, the efficiency depends on how you drive your car. The below points explain what not to do while driving a turbo engine-powered car.

  • Never turn on the engine and drive straight away. Always warm up the engine before you drive. Warming up allows the engine oil to come to an optimal operating temperature. A well-lubricated engine and turbo are essential for the efficient functioning of the engine.

  • Do not shut down the engine immediately after you push the engine to its limits or drive aggressively. Allow some time (a few minutes) to cool down the essential fluids and then swift off the engine.

  • Avoid lugging the engine by driving at a slower speed in higher gears. It puts a lot of stress on the engine components.

  • Do not step on the throttle aggressively if there is a turbo lag. If you accelerate suddenly, the turbo will take a few seconds to spool up. But when it spools up, the sudden surge of power may catch you off guard, and you may lose control of the vehicle.

  • Never use lower octane fuel in a turbocharged engine. Refer to the owners manual and use the correct octane level fuel.

Also, read: Car Engine Types

List of best turbo engine cars in India

Here’s the list of best turbo engine cars available in India.

Turbo-diesel engine cars in India

Below are the turbo-diesel engine cars available in India.

Mahindra XUV700 Tata Nexon Hyundai Venue
Mahindra Thar Hyundai i20 Kia Sonet
Hyundai Creta Toyota Fortuner MG Hector
Kia Seltos Mahindra XUV300 Hyundai Verna
Tata Harrier Toyota Innova Crysta

Turbo-petrol engine cars in India

Here are the turbo-petrol engine cars in India.

Hyundai Grand i10 Nios Tata Altroz
Nissan Magnite Skoda Rapid
Kia Sonet Tata Nexon
Hyundai Venue Volkswagen Polo
Hyundai Aura Hyundai i20

Frequently asked questions

If you still have any questions about turbo car engines, the below queries may clear your doubts.

Does a turbocharged engine consume more fuel?

Generally, turbo engines are efficient due to their smaller capacity. However, the fuel economy depends on your driving style. If you are gentle on the throttle, you can expect a good fuel economy, and if you drive aggressively, a turbo engine may consume more fuel.

Is a turbo engine better than a normally aspirated engine?

Yes, a turbocharged engine is better than a normal engine in terms of performance and efficiency. A lower capacity turbo engine can produce the same amount of power as a higher capacity NA engine.

Is a turbo engine-powered car good for city driving?

Yes, a turbo engine car can be good for city driving. An engine fitted with a turbo produces more torque lower down the rev range, and it improves the low-end performance, which is required to drive on busy roads.

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