Recently, I was at a gathering with friends when the conversation turned to cars.
None of them were really car people so we weren’t exactly discussing the minutiae of motoring, but the conversation turned to engine size.
Someone asked me how big the engine in her small hatch was, to which I replied 2.0 litres.
Her brow creased and head tilted to the side.
“But … I put way more than two litres in at the servo?”
It was a teachable moment, at least.
So if you think a camshaft has something to do with photography, here are some basic terms to master so at least you can fake it at a barbecue.
Capacity — Also called displacement, this refers to the total amount of air and fuel the cylinders can accommodate in a single cycle. It is measured in cubic centimetres (cc) in Australia or, more often with cars, in litres.
If you’ve got four cylinders which can handle 500cc each, you have a 2.0-litre engine.
The more cylinders you have, the bigger the overall capacity will be, which is why you won’t find a 2.0-litre V8.
Power/torque — The Top Gear guys used to joke no one knows what torque actually means, and it can get murky.
Essentially, a car’s torque (measured in Newton metres) is what the engine is capable of doing, the power (measured in kilowatts here but also in horsepower) is how fast it can do it. In its simplest terms, a car with a lot of power but not much torque will need a lot of revs and the engine to work hard to generate its power.
A car with lower power but a lot of torque won’t be fast but could, say, tow something heavy.
A car with lots of torque and power will be an absolute weapon.
Turbocharged/supercharged — Both cram more air into the engine for improved performance but in different ways: a turbocharger uses exhaust gases. A supercharger is powered by the engine.
Turbos can better maximise the output of smaller engines, meaning fuel economy is generally better. Waiting for those gases to make it through the exhaust can result in a delayed power supply (turbo lag) and sometimes a surge in power once it kicks in. There is no lag with a supercharger.
Turbos generally operate best at higher revs, whereas superchargers offer good power boost, even at low rpm. But turbochargers’ efficiency and emissions benefits are largely why they are far more common than superchargers.
BEV — Not just the lady who owns the local deli. A battery electric vehicle is completely powered by a battery, which you need to charge by plugging in.
PHEV — Not just the former Carlton full-forward. A plug-in hybrid electric vehicle has a normal combustion engine and a battery which can power the car for short distances, usually 30-60km, which needs to be charged by plugging in.
HEV —No plugging in here. This pairs a battery with a normal engine but the battery is charged by braking and coasting and will only kick in here and there when able.
Manual — We’re confident you’re across this already.
Automatic — aka a conventional or torque- converter automatic.
Uses a torque converter to change gears instead of a clutch. A simple, hassle-free option which is cheap but can suffer on fuel economy and be slow to respond.
Dual clutch — Uses two separate shafts for changing gears — one for odd-numbered gears, the other for even.
Good for fast changes and performance but can also be jerky and expensive.
CVT — Instead of gears, a continuously variable transmission uses belts and pulleys which respond to rpm.
Good for fuel economy, not always great for performance driving or engine noise.