What is a supercharger and what does it do?

author

Rowan Johnstone

Thursday, 27 June 2019

 

A supercharger is a device that’s fitted to an engine with the sole purpose of ramming as much air into it as possible.

More air means more fuel can be mixed in ready for ignition, and the result is a considerable boost in power output.

Superchargers run off the power of the engine and unlike turbochargers they experience next to no lag in their power delivery.

The power surge from superchargers can be felt instantly and can be accessed across the entire RPM range.

Whilst different types of superchargers deliver their power in different ways, this generally holds true for them all.

Additionally, some would say that the mechanical ‘whine’ of a supercharger is one of the most addictive sounds that a car can make, and that in itself is reason enough to bolt one on.

Different types of superchargers and how they work

There are three types of superchargers that are used in the automotive world:

Roots-type supercharger

The ‘original’ supercharger, and a design that has been around since about 1860, these essentially work as air accelerators, where they force air into the intake manifold at a ferocious rate.

The drawbacks of a Roots-type supercharger is that it becomes less efficient the hotter it gets - as the RPMs increase and the pressure increases, the power output of the supercharger decreases causing a power drop off at higher revs.

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Centrifugal supercharger

Whilst still generating its power from engine speed, a centrifugal supercharger operates as an air compressor, so while they still provide boost at low RPMs, there’s not as much.

These superchargers can be closely linked to the way a turbocharger works in that boost and power are increased as engine speed increases.

Whilst you won't experience any lag between acceleration and power with a centrifugal supercharger like you would with a turbocharger, you will feel a steady increase in power as the supercharger gets up to speed and generates more boost.

Twin-screw supercharger

This supercharger works as a compressor and offers consistent power from idle speed all the way through to redline.

The benefits of a twin-screw supercharger is that you get the full output even at low revs, and there’s no power drop off through the rev range.

This is partly due to them not running as hot as the Roots-type supercharger.

The downside is these superchargers are very technical bits of equipment!

Set-ups that support a twin-screw supercharger must be highly engineered with no room for error.

This results in a much more expensive power delivery system than the previous two types of superchargers.

If your car is having problems and you suspect it’s the supercharger, don’t hesitate in booking in with a Performance Specialist on AutoGuru.

A fully qualified, local mechanic is the best person to figure out your supercharger woes.

author

WRITTEN BY

Rowan Johnstone

On weekdays Rowan can be found in the AutoGuru office, driving content and growth with the rest of the marketing team.

On weekends you’ll probably find him in the garage with his father restoring a 1958 Ford Star Model Customline or enjoying a cruise through the Gold Coast hinterland on his Yamaha XV250.

Despite his automotive passion, Rowan looks forward to the day when he can commute to work in his own driverless car.

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