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Turbochargers vs. Superchargers: What’s the Difference?

Two different means of achieving forced induction

Turbochargers and superchargers both perform the same basic function: they compress and push more air into the engine—generating pressure or “boost”—allowing more fuel to be used, and thus helping the engine produce more power. This whole process is known as forced induction, but because turbochargers and superchargers go about achieving this in totally different ways, it would be a mistake to refer to them interchangeably.

So, turbochargers vs. superchargers: what’s the difference?



Power Source

The main difference between turbochargers and superchargers is how they are powered. Both draw air from a separate intake before compressing it and feeding it to the engine, but while superchargers are driven directly by the engine via a drive belt connected to the crankshaft, turbochargers are powered by exhaust gasses that spin a turbine on their way out of the engine.

Though there are numerous kinds of supercharger designs, their main job is essentially to convert engine power into even more engine power; on the other hand, by using exhaust gasses as their power source, turbochargers recycle what would otherwise be wasted energy.

Boost Characteristics

The different designs of superchargers and turbochargers cause them to have various boost characteristics, thus giving each a unique feel when behind the wheel. Most superchargers always move the same amount of air at any given RPM, creating a linear power curve and allowing them to make boost immediately, including at low RPMs. This makes them ideal for drag racing.

On the other hand, turbochargers have an exponential power curve as they build up turbine speed and pressure, also known as spooling up. This is what causes “turbo lag,” the feeling of the turbocharger finally kicking in with a delayed response after putting your foot down on the throttle. Because of this, turbochargers are often preferred on race cars where revs are expected to be kept high at almost all times.



Performance

Though turbochargers require more parts to build and more skill to properly configure, they can potentially produce more boost than a supercharger and do so more efficiently. Superchargers are less complex and less efficient, but cheaper to build and maintain when you want a quick-and-easy way to tune up your car.

Despite being minimal on most modern turbocharged cars, turbo lag nonetheless remains one of the reasons some enthusiasts prefer the direct, responsive feel of naturally-aspirated engines. It is also one of the reasons high-performance turbocharged cars have begun using hybrid powertrains, as electric motors generate instant torque and thus compensate for turbo lag at low RPMs (also known as “torque fill”); this is best exemplified in cars like the McLaren P1, Acura NSX, or even the post-2014-regulation Formula 1 race cars.

Conclusion

Turbochargers and superchargers fulfill different needs. Though superchargers aren’t necessarily wasteful, they do require the engine to already produce a decent amount of power to operate efficiently. Turbochargers are theoretically better at being efficient and at producing boost, but have clearer downsides like turbo lag and complexity. However, in the current automotive era where high fuel economy and low emissions are prioritized, it’s no surprise that downsized engines with turbochargers have taken over, while superchargers have been left to the performance enthusiasts and tuning houses.