Turbocharger vs. Supercharger: What's the Difference?

What's The Difference Between A Turbocharger And A Supercharger?

"Supercharger" is the generic term for an air compressor used to increase the pressure or density of air entering an engine, providing more oxygen with which to burn fuel. The earliest superchargers were all driven by power taken from the crankshaft, typically by gear, belt, or chain. A turbocharger is simply a supercharger that is powered instead by a turbine in the exhaust stream. The first of these, dating to 1915, were referred to as turbosuperchargers and were employed on radial aircraft engines to boost their power in the thinner air found at higher altitudes. That name was first shortened to turbocharger and then to turbo.

Which Is Better: Turbo- Or Supercharger?

Each can be used to increase power, fuel economy, or both, and each has pros and cons. Turbochargers capitalize on some of the "free" energy that would otherwise be completely lost in the exhaust. Driving the turbine does increase exhaust backpressure, which exerts some load on the engine, but the net loss tends to be less by comparison with the direct mechanical load that driving a supercharger involves (the biggest blowers powering a top-fuel dragster consume 900 crankshaft horsepower in an engine rated at 7,500 total horsepower). But superchargers can provide their boost almost instantly, whereas turbochargers typically suffer some response lag while the exhaust pressure required to spin the turbine builds. Clearly a top-fuel dragster trying to run the quarter in four seconds has no time to waste waiting for exhaust pressure to build, so they all use superchargers, while vehicles tasked with boosting a company's corporate average fuel economy (CAFE) can't afford to squander precious horsepower on blowers, so they mostly use turbos. But with the rise of mild hybridization and 48-volt electrical systems, you can expect to see greater use of superchargers driven by freely recuperated electricity stored during deceleration and braking. Mercedes-Benz's new M256 six-cylinder now arriving in vehicles like the CLS 450 and GLE 450 uses just such a system, as does the similarly sized and configured range-topping engine in the new Land Rover Defender.