What’s the difference between a turbocharger and a supercharger?

Superchargers, turbo and boost, oh my! Previously found only on racing cars or on high-performance models, turbo and superchargers are actually becoming increasingly common on smaller cars.

You’ve maybe heard the terms before, or you might even own a turbocharged or supercharged car, but what do they actually do? Most people will probably be vaguely familiar with the fact that they improve a car’s performance, but how and why would you want one?

As it turns out, turbo and superchargers aren’t just for car park cruisers or racing drivers, they can have some real benefits for the average motorist too.

If you’re interested in learning more, we’ve put together a quick FAQ to answer some of the more commonly asked questions about them and to weigh up the pros and cons of each:

What are turbo/superchargers?

Turbochargers and superchargers are both devices used to boost the horsepower of your car by forcing air into the combustion engine which powers your car.

Simply put, a car or van with a turbo or supercharger will behave like a vehicle with a larger, more powerful engine, boosting its speed, power and acceleration.

How do they work?

Both work on exactly the same principle, by pushing extra air into the cylinders in your car’s engine. Combustion engines work by burning air and fuel together, which creates the explosion necessary to move the pistons on the engine, which then turn the wheels to make the car move.

By forcing more air into each cylinder – a process known as ‘forced induction’ – the engine can burn fuel more quickly, producing more energy to turn the wheels faster, which makes your car travel quicker as a result.

What’s the difference between a turbocharger and a supercharger?

While the theory behind turbochargers and superchargers is essentially the same; both use fans to suck in extra air, which is then compressed and forced into the engine cylinder in order to produce the boost effect. The key difference is in the way they operate.

Turbochargers use waste gases from the engine in order to make the fan spin. When waste gas leaves the engine, it travels along a pipe where it spins a little rotor before going to the exhaust; kind of like the toy windmills you used to play with as a kid.

Each rotor is attached to a fan which scoops in air from the engine’s air inlet, before sending it up a pipe to the compressor, before it’s pumped into the engine and the process repeats.

Superchargers work on a similar principle, where a fan sucks in extra air and compresses it, but the fan rotor on a supercharger is powered by the movement of the engine itself, and not from waste gases.

The key difference between the two therefore is that superchargers require engine power to run, while turbochargers run off waste energy created by the engine itself.

Does my car need one?

While turbo and superchargers are obviously great additions for somebody who wants to squeeze as much speed and power out of their car as possible, they also have some pretty good knock-on effects for the average driver.

In the effort to make engines more efficient and less harmful to the environment, the general industry trend recently has been to downsize the power units themselves.

Increasing numbers of manufacturers are turning to smaller engines to cut fuel costs and lessen CO2 emissions, but the downsizing of engines usually translates to a loss in power.

The advantage of using forced induction on a smaller engine, therefore, is that you get all the benefits of a small frugal engine, but keeping the same amount of power and driveability as a much larger engine.

Just some of the cars that now come with turbochargers include Vauxhall’s latest Corsa, which has the option of a turbocharged three-cylinder petrol engine, and various models in Ford’s range which come with the turbocharged EcoBoost engine.

Why a turbocharger?

Like anything, a turbocharger comes with its own unique set of pros and cons. The most obvious benefit to drivers is a significant increase in horsepower, which will translate into more speed on the road.

A turbocharger also maximises the power to size ratio of a smaller engine, meaning that even a relatively small three-cylinder engine like that in a Corsa can produce enough power for a pretty impressive drive.

This will also translate into better fuel economy, while turbochargers are also highly efficient as they’re powered by waste exhaust gases that are expelled from the engine while it’s running.

Of course, turbochargers also suffer from some downsides, one of the common of which is referred to as ‘turbo lag’.

The problem with relying on exhaust gases to power the turbocharger fan is that it takes some time to reach the speed necessary to really get the air forced into the engine’s cylinders. As a result, it can take some time for the turbo to actually deliver the power boost.

An offshoot problem of this is that some can deliver too much power too suddenly; once the turbocharger fan reaches the right speed it can deliver a huge power boost, causing your wheels to spin and potentially compromising traction.

Finally, in a car which doesn’t come with a turbocharger fitted as standard, they can be rather expensive to buy, as it requires a significant modification to your engine system.

Why a supercharger?

On the flip-side, a supercharger doesn’t suffer from the same turbo lag as a turbocharger, namely because the fan is powered by the engine, which is always running when the car is switched on.

This means that as soon as you put your foot down you’ll feel a significant power boost, while superchargers are generally often a bit more reliable than turbochargers, require less maintenance and are easier to fit to your car.

Cons of a supercharger mainly stem from the fact that they require power from the engine itself in order to run, meaning that you’re essentially powering your engine with power from the engine. Superchargers therefore are a bit less efficient than turbochargers.

Other problems with superchargers are the fact that they can generate extreme levels of heat, and they also tend to be quite a bit noisier than turbochargers. Some drivers like this, however, due to the signature ‘whooshing’ sound a supercharger can make.

Anything else?

Which you prefer largely comes down to you as a driver and the car you have, though looking at things simply it can boil down to a choice between extra efficiency and more power.

Turbochargers tend to be the most common, however, particularly in newer cars as they can boost power in smaller engines without detracting for their frugality, while superchargers are more at home in large-displacement engines like V8s to extract the most possible power.

Electrically-powered turbochargers will also likely become more and more common in future vehicles in a bid to combine the best elements of both turbo and superchargers, though they’re still a bit off yet.

For more information or to take a look at the range of new and used cars we stock, why not check out our website or get in touch with your local Perrys dealership today?