How Does a Supercharger Work?

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Article QuickTakes:

• The workings of a supercharger
• Four types of superchargers
• Supercharger availability
• Superchargers vs. turbochargers
• Forced induction considerations

A supercharger works by increasing an engine's power and torque. It compresses the air the engine takes in, often called forced induction. Patented by Gottlieb Daimler in 1885, European car models popularized them throughout the 1920s and 1930s. Later, supercharged engines powered certain Allied airplanes during World War II. Although they're often found in high-performance models, there are a few less extreme versions for sale today.

The Workings of a Supercharger

An internal combustion engine sucks air into a cylinder where it's compressed, igniting a blend of fuel and air. Once ignited, it generates a power stroke of the piston before sending energy to the wheels. When an engine's displacement is relative to a vehicle's design, it supplies a corresponding level of performance. When more power is needed, a larger engine will get the job done, but so will a forced induction system such as a supercharger.

Superchargers are belt-operated and most often powered by an engine's crankshaft. This type of forced induction is different from a turbocharger, which utilizes waste heat from the exhaust.

When a supercharged car is running, the engine pulls air through the intake, hood scoops, and any other entry points. Next, the supercharger compresses the air which increases the air's pressure and density. This way the engine receives more air through the same intake, which allows it to burn more fuel resulting in a boost in performance.

However, that boost comes at an upfront cost. Notably, a loss of horsepower of as much as 20%. On the other hand, a supercharger produces far more horsepower than the belt drive takes from the engine, thus the net increase in horsepower is somewhere between 30% and 50%.

Four Types of Superchargers

Not all superchargers are alike. Indeed, there are some differences between the four types available:

• First, the Roots supercharger is the oldest of the group. This one utilizes a pair of rotors to capture air and send it to the intake manifold, pressurizing the intake manifold between the supercharger and the engine.
• Second, the twin-screw supercharger is similar to the Roots in appearance. Instead of compressing air in the intake port, it does that within the supercharger housing by forcing air between two interwoven screws.
• Third, the centrifugal supercharger takes a different approach. This design dispenses with rotors in favor of an impeller fan to suck air into an intercooler or straight to the engine.
• Fourth, is an electric supercharger, which is the newest of the group. This one works like a centrifugal supercharger, but it uses an electric motor to pressurize the intake air. It is found in a few 48V hybrid systems.

Supercharger Availability

As a type of boosting technology, superchargers are a sought-after feature. They're the driving force in the 6.2L V8 engines powering Dodge Challenger and Charger Hellcat models. They have a signature sound too, which is a high-pitched wine when they're creating boost.

You'll also find them available in the Land Rover Range Rover Sport, various Jaguar models, the Jeep Grand Cherokee Trackhawk, Chevrolet Camaro ZL1, and the Ford Mustang Shelby GT500. Moreover, superchargers are also a popular aftermarket addition for enthusiasts.

Superchargers vs. Turbochargers

Where superchargers offer excellent upfront grunt, another form of boosting technology is turbochargers, which are bolted to the engine's exhaust manifold.

Turbochargers spool up further along the power curve and bring sustainable torque, whereas a supercharger may fade after its initial boost. Turbos are utilized far more than superchargers by automotive manufacturers.

In an unusual twist, Volvo offers both supercharger and turbocharger technology as optional equipment with its 2.0L four-cylinder engine. This combination delivers a powerful 1-2 performance punch under strong acceleration.

Forced Induction Considerations

Now that you can answer the question, how does a supercharger work, you might consider forced induction for your next new vehicle purchase. Generally speaking, superchargers are less fuel efficient than conventional and turbocharged engines, and (as with turbos) almost always require costlier premium-grade fuel to operate.