What does engine size mean?

What does engine size mean?

We explain in this guide how engine size is measured and why the size of an engine is important when choosing a car to buy.

When a car is talked about by a manufacturer or reporter, often it is mentioned what the size of the engine in the vehicle is.

A lot of importance is placed on the size of a car’s engine, as well as its power and torque, but some may wonder why engine size is such a big deal in the first place. In this guide, we discuss what exactly people are talking about when mentioning engine size and how much influence size has on an engine and the car that uses it.

What is engine size?

Usually when someone is discussing the size of a car’s engine they refer to how much space the engine’s pistons operate in. The bigger the engine size number, the more air and fuel each piston can push when they move, leading to more engine power.

Bear in mind that while the amount of power an engine can produce does depend on its size, another major influence is whether or not it uses a turbocharger or supercharger. Turbochargers are especially popular on many modern small cars on the market nowadays.

Engine size is usually measured in cubic centimetres (cc), with 1,000cc equating to one litre (or 1.0-litre as a manufacturer or motoring magazine would write it).

With engines that have a capacity or displacement near or greater than 1,000cc, it is typically rounded up to the nearest tenth of a litre. So, if a car is available with an engine that has a capacity of 1,498cc for instance, it will be described as a 1.5-litre engine.

These cc/litre figures refer to the combined capacity of all the engine’s cylinders. So, if for instance you see an engine describe as a 2.0-litre, four-cylinder unit, that means the engine has an estimated capacity of 500cc in each of its cylinders. It is inside the cylinders where the piston moves up and down. The space in which these pistons move is known as the combustion chamber and it’s here where an engine burns fuel to produce power.

Engine size also majorly affects the fuel economy of a car. If two cars which are identical except the size of the engine they use complete an identical journey, then the car with the smaller engine is more likely to use less fuel (though various other factors like the weight of the two cars have an influence too of course). So while a larger engine may sound tempting and may even feel necessary on a larger, heavier vehicle, it’s a decision worth thinking about carefully as long-term running costs will need considering.

What is engine displacement?

‘Engine displacement’ is an alternative term to ‘engine capacity’ which can be used to refer to an engine’s size.

Types of car engines

While the size of an engine has influence over how much power it can offer and subsequently a car’s performance abilities, there are also sorts of different technologies and layouts which an engine can utilise which influences the size deemed necessary and the performance figures it ultimately extracts.

You can find more on car engine types in our guide to car engine layouts.

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