What is a supercharged engine?

They sound exotic and make your car go faster. But what is a supercharged engine?

John Evans
Sep 10, 2018

The supercharger was born out of motor racing, and while it has nothing to do with electrification, it does make a car faster.

In recent years it has fallen out of favour because, like the car’s water pump or alternator, a supercharger takes its power from the engine. In other words, to make power, it uses power. This adversely affects the car’s performance and its fuel consumption - not good when manufacturers are under pressure to make more efficient cars.

Because they’re more efficient, turbochargers have to a large extent replaced superchargers.

Even so, there are still some supercharged cars on the market so here’s what you need to know about the technology.

How does a supercharger work?

The supercharger is powered by the engine, via a pulley attached to the crankshaft. The faster the engine turns, the faster the little impeller inside the supercharger spins. The impeller compresses the incoming air and allows more of it to be directed to the engine, where it produces more power.

The faster the engine turns, the more compressed air the supercharger produces, and the more power the engine makes.

    

What cars have a supercharger?

There aren't that many new cars using the technology, but in recent years, the first-generation Mini Cooper S of 2001-6 was supercharged, as was the Mercedes SLK 200 Kompressor of 2004-10.

Today, VW champions supercharging as a way of increasing efficiency but only in combination with a turbocharger, which is powered by the exhaust gases and not directly by the engine.

Its new 1.5 TSI Evo engine that powers some versions of the latest Golf has a turbocharger and a supercharger, in what the company calls twin charging. In this engine the supercharger works at lower engine speeds, with the turbocharger, powered by the exhaust gases, coming into power as the revs rise.

How do I recognise a supercharged engine?

It’s quite difficult since car makers tend not to make much noise about supercharging, while others will use a turbocharger or a supercharger or even both together, yet still badge them the same.

Some Audi TFSI engines are supercharged. VW badges it TSI. Examples include the Golf, T-Roc (shown above), and Arteon.

       

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