Choosing a Supercharger Versus Turbocharger

Performance

DIY

Engines and Components

Mark Bach

October 11, 2023

Mark Bach

October 11, 2023

Adding a blower is a relatively simple way to improve combustion and thereby boost engine power. But is it better to use a supercharger - opens in new window or tab. or a turbocharger - opens in new window or tab. to get the extra oomph?

Superchargers and turbochargers both force compressed air into the engine via a turbine. The difference is in the drive mechanism.

Supercharging compresses the incoming air charge, making it more dense, giving the engine the opportunity to burn more fuel. Compressed air speeds up the combustion process, the flame burns hotter and faster, ensuring a more complete combustion event.

A larger, more-efficient supercharger flowing more air through the engine was key to helping produce the massive 650 horsepower in the 2013 Ford Shelby GT500. — A large supercharger flows more air through the engine to help produce the massive 650 horsepower in the 2013 Ford Shelby GT500.

A supercharger is belt-driven off the crankshaft - opens in new window or tab., while a turbocharger is driven by exhaust gasses. Because a turbocharger is driven by waste energy from the engine, it is more efficient than a supercharger, which requires engine power to run.

2.0-liter four-cylinder Ecoboost engine using turborcharging.

In the past, do-it-yourselfers favored superchargers since they didn’t suffer from turbo lag and oil coking problems in the turbo bearing housing.

Oil coking occurs when the oil breaks down due to excessive heat and leaves deposits on engine parts.
Turbo lag is a delay between the driver pressing the accelerator and the turbocharger finally kicking in to produce more power.

Advances in technology have mitigated both these issues. A turbocharger’s compact size, combined with its ability to reduce toxic emissions and improve low-end torque, makes it an appealing option.

Comparing Superchargers and Turbochargers

Packaging

Since superchargers are larger than turbochargers, they fit best into a V-8 engine with a wide 90-degree bank. Turbochargers are a better choice for V-6 engines that typically have a narrower 60-degree bank, as well as inline engines.

A supercharger needs to be able to reach the fan belt, and it must be located on the same axis as the crankshaft that drives it. A turbocharger should be located as close as possible to the cylinder head exhaust port, where the air charge is hot and dense.

Lag Time

Throttle lag has long been the bane of turbochargers. Engineers have reduced turbo lag by making the units smaller so they take less time to spool up, and some engines use twin turbos - opens in new window or tab. to reduce this lag. Turbo lag is most noticeable at low engine speeds, which is why turbochargers tend to work better on fast-spinning small engines.

Shop now for superchargers - opens in new window or tab.

Superchargers have no lag because they are directly driven off the crankshaft, but here’s the rub: They are always running and make power whether you want it or not. There is also a noticeable, constant whine from the supercharger. The fix is to throttle the power upstream or allow the air charge to recirculate.

Fuel Economy

Here, turbochargers have a distinct advantage. If the engine is under low load, the turbo won’t kick in. Because a supercharger is belt driven off the crankshaft, the blower continues to spin even under a light load, adversely impacting fuel economy.

Torque Versus Horsepower

Turbochargers are better than superchargers for producing low-end torque because they spin at more than twice the speed of a supercharger.

There are two types of superchargers. Positive displacement designs, such as Whipple - opens in new window or tab. and Eaton superchargers - opens in new window or tab., make the same amount of boost all the time. They are best suited for towing applications because of their ability to enhance low-end power. Centrifugal superchargers, such as those from Vortech - opens in new window or tab. and Paxton - opens in new window or tab., vary the amount of boost according to engine load, so they are better for high-performance applications and racing.

Cylinder Imbalance

V-8 engines have an uneven firing order that creates a difference in power from cylinder to cylinder. Turbochargers tend to exaggerate this problem because of the way they boost low-end torque. On the other hand, superchargers smooth out these cylinder-to-cylinder imbalances.

Maintenance

Superchargers have the advantage because they are self-contained units. Turbochargers depend on the engine’s oiling system. Although oil coking is less of a problem than it used to be, owners of older turbocharged vehicles should let the engine idle briefly before shutting it off to let the turbo housing cool down. Some technicians believe that a water-cooled turbocharger is less likely to have coking problems than an oil-cooled unit.

Bottom Line

The choice between supercharging and turbocharging depends on the size and configuration of the engine, fuel efficiency, and emissions considerations. If you want to add more power to your late-model muscle car’s V-8 engine, supercharging is the best option. But turbocharging is a better solution for boosting power and efficiency on small engines. Both options will make the engine breathe more efficiently, resulting in better overall performance.

Shop now for turbochargers - opens in new window or tab.

About the author

Mark Bach

Mark C. Bach has oil in his veins and remembers feeler gauges and brake springs. He has a love for all things that move, especially old-school muscle cars. Bach writes for a variety of outlets, including Chevy Classics and FuelCurve.com, and maintains Route66pubco.com.

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This article is meant to provide general guidance only. Automotive maintenance, repair, upgrade, and installation may depend on vehicle-specifics such as make and model. Always consult your owner's manual, repair guide for specific information for your particular vehicle and consider a licensed auto-care professional's help as well, particularly for advance repairs.