What is the difference between a turbocharger and a supercharger on a car engine?

In the quest for higher performance and fuel economy in automobiles, two formidable technologies have risen to prominence: turbochargers and superchargers. Both devices are designed to boost the power output of an engine without increasing its size, but they do so in remarkably different ways.

So, in a battle between the two engine boosters — turbo vs. supercharger — which is better? In this article, we'll demystify these technologies, exploring the nuances between turbocharged and supercharged engines, and shedding light on their respective advantages and disadvantages.

United By Forced Induction

Let's start with the similarities. Both turbochargers and superchargers are called forced induction systems. They compress the air flowing into the engine (see How Car Engines Work for a description of airflow in a normal engine). The advantage of compressing the air is that it lets the engine stuff more air into a cylinder. More air means that more fuel can be stuffed in, too, so you get more power from each explosion in each cylinder. A turbo/supercharged engine produces more power overall than the same engine without the charging.

The typical boost provided by either a turbocharger or a supercharger is 6 to 8 pounds per square inch (psi). Since normal atmospheric pressure is 14.7 psi at sea level, you can see that you are getting about 50-percent more air into the engine. Therefore, you would expect to get 50-percent more power. It's not perfectly efficient, though, so you might get a 30-percent to 40-percent improvement instead.

How Much Power Is Enough?

The key difference between a turbocharger and a supercharger is its power supply. Something has to supply the power to move the compressed air. In a supercharger, there is a belt that connects directly to the engine. It gets its power the same way that the water pump or alternator does.

A turbocharger, on the other hand, gets its power from the exhaust stream. The exhaust runs through a turbine, which in turn spins the compressor. Now let's explore the turbo vs supercharger debate in greater detail!

Turbochargers: Harnessing Exhaust Gases

The key advantage of a turbocharger is its ability to recycle waste energy from the exhaust gases, making it a highly efficient method to boost engine power. There's also the potential to create a twin turbo configuration.

Pros of Turbocharging:

Improved fuel efficiency: By using exhaust gases to generate extra power, turbocharged engines can achieve better fuel economy compared to naturally aspirated counterparts.
Increased power: Turbochargers can significantly enhance engine power and torque, particularly at higher RPMs.
Reduced engine size: Engines equipped with turbochargers can be smaller in size but still produce the same, if not more, power as larger, naturally aspirated engines, contributing to weight savings and improved vehicle dynamics.

Cons of Turbocharging:

Turbo lag: The time delay between the moment the accelerator is pressed and when the turbocharger delivers significant boost can be noticeable, affecting responsiveness.
Complexity and cost: Turbocharging systems can be complex and costly to repair or replace due to their reliance on high-speed components and exhaust gas management.

Superchargers: Direct Engine-Driven Power

Unlike turbochargers, superchargers are mechanically driven via a belt connected to the engine's crankshaft. This direct connection forces more air into the combustion chamber, similar to turbochargers, but without relying on exhaust gases. The immediate response of superchargers offers a distinct advantage in terms of throttle response.

Pros of Supercharging:

Immediate response: Superchargers provide an instant boost in engine speed without the lag associated with turbochargers, resulting in better throttle response and acceleration.
Simplicity: Superchargers are generally simpler in design compared to turbochargers, making them easier and less expensive to maintain.
Versatility: They can be used in a wide range of applications, from small cars to high-performance sports cars and even heavy machinery.

Cons of Supercharging:

Reduced fuel efficiency: Since superchargers draw power directly from the engine, they can reduce fuel economy, especially under heavy acceleration.
Engine pressure: The mechanical connection to the engine means that superchargers can put additional strain on the engine, potentially leading to increased wear and tear.

Choosing Between Turbo and Supercharged

The choice between turbocharging and supercharging ultimately depends on the specific needs and preferences of the driver. If fuel efficiency and high-end power are priorities, a turbocharged engine might be the way to go.

On the other hand, for those who value immediate throttle response and simplicity, a supercharged engine could offer the most satisfaction.

The Future of Engine Boosting

As automotive technology continues to evolve, manufacturers are exploring innovative ways to combine the benefits of both turbochargers and superchargers.

Some are developing electrically assisted turbochargers that eliminate turbo lag, while others are experimenting with hybrid systems that use both a supercharger for low-end power and a turbocharger for high-end efficiency.

Two Sides of the Internal Combustion Engine

The debate between turbocharged and supercharged engines is as much about personal preference as it is about technological distinction. Each system has its unique set of advantages and challenges, making them suitable for different types of vehicles and driving styles.

As automotive technology advances, the lines between these two boosting methods may blur, leading to more efficient, powerful, and responsive engines. In the end, whether turbocharged or supercharged, the goal remains the same: to maximize the performance and efficiency of the modern car engine.

This article was updated in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.

Turbo Vs Supercharger: Comparing Car Engine Boosters