A Jump Start to Motoring Basics: Engine Size Explained

For many, buying a new car in 2010 means sifting through a mind-boggling array of acronyms that make up the technological achievement that is the modern automobile. But even before one has to deal with those acronyms, comes the challenge of figuring out what size engine should be fitted to the vehicle you’re paying too much money for. In many cases, I come across drivers who don’t know that they drive a 1.6-litre or a 1300 so for this post, I’ll be explaining what the numbers affixed to your car’s rear end signify. The letters, like “GTi”, “GLE” and TSi… well, that’s for another post entirely.

Most cars are fitted with internal combustion petrol engines. These have pistons that travel inside cylinders – okay, that is already getting rather technical – but all you need to know is that the pistons and cylinders are the greasy bits that move up and down inside your engine, compressing a mixture of fuel and air until a spark ignites it, thereby generating the power that propels you past the Golden Arrow bus blocking your path.

So, engines contain cylinders and cylinders contain pistons. The size – or displacement – of your engine is the maximum amount of space in the cylinders that can fill with air and fuel. Engine displacement is measured in either cubic centimetres (cc) or litres. A 2.0-litre engine will therefore have a total displacement of approximately 2000 (a 1989cc engine will be rounded off and referred to as a 2.0, not a 1.989-litre!) cubic centimetres. In comparison to a 1.6-litre, a 2-litre engine obviously has a larger capacity and therefore the ability to pump a greater amount of air/fuel which enables it to produce more power than the average 1.6.

"325" denotes a "3 Series BMW" fitted with a 2.5-litre motor

A common motoring adage says that “there is no replacement for displacement” and it largely holds true. The easiest way – alongside forced induction - to generate more power out of an engine is to increase its size. Of course, engine size generally correlates to the size of the vehicle – this is why you will never see a Fiat Uno 4.0-litre cruising by. If you do see such a car, it will more likely be flying to the moon than cruising.

A CitiGolf fitted with a 1400cc motor and a diagram of an internal combustion motor with 4 cylinders. The coloured areas represent the engine's displacement.

Of course, the obvious disadvantage of larger engines is that because they’re able to pump a larger amount of an air/fuel mixture, they’re heavier on fuel. Also, whether presented as a 1600, 160 or 1.6, these are all engines with a displacement that is the same or similar enough to make no real difference.

Perhaps the next oversight that many make when relating to engine size is that a 1600 is definitely faster than a 1400. However, there are many variables that one has to take into account when comparing the performance of two vehicles. For example, a 1.6-litre VW Citi-Golf is faster than a VW Jetta fitted with a 2.0-litre. Even though the Jetta has a larger engine and produces more power, it is much heavier.

For a more accurate (but never entirely perfect) performance comparison, one has to take into account the power to weight ratio of a vehicle – this figure can be used to compare vehicles in different segments and with different sizes of engine.

So, there we go. A basic guide to engine capacity/size/displacement explained… may you now nod knowingly at the thousands of 180i Corollas, 1.6 Polos and 1.4 Fiestas as they whizz by you.