Forced Induction

Turbochargers and superchargers are essentially air compressors that shove more air into the engine.


Benefits: More power without an increase in engine size

Drawbacks: Fuel consumption, turbo lag

An engine requires three things to generate motion: fuel, air, and ignition. Cramming more air into an engine will increase the power generated by the engine's pistons. A long-standing way to do that, and one that's becoming increasingly popular as of late, is to use forced induction. You may know this process better by the parts that do make it happen -- turbochargers and superchargers.

In a forced induction engine, air is forced into the combustion chamber at a higher pressure than usual, creating a higher compression and more power from each stroke of the engine [source: Bowman]. Turbochargers and superchargers are essentially air compressors that shove more air into the engine.

Forced induction systems were used on aircraft engines long before they started being added to car engines in the 1920s. They are especially beneficial for small engines as they can generate a lot of extra power without increasing the engine's size or causing a dramatic drop in fuel economy.

A good example is the turbocharged Mini Cooper S, which only has a 1.6-liter engine but produces more than 200 horsepower in some applications. In addition, high-performance cars like the Porsche 911 Turbo or Corvette ZR-1 use forced induction to achieve tremendous gains in power.

The drawbacks? Cars that have turbochargers often require premium gasoline. Then there's the issue of turbo lag, where the power gains aren't felt until the turbocharger spools up at higher revolutions per minute (RPM). Engineers have helped reduce both of those drawbacks in recent years.

And with fuel economy and emissions standards getting stricter, many carmakers are turning to forced induction on smaller engines instead of building larger engines. On the newest Hyundai Sonata, for example, the top engine one can buy is no longer a V6, but a turbo four-cylinder.

Next up, we'll discuss why carburetors have practically become a thing of the past thanks to fuel injection.