Turn the key and fire the engine: suck, squeeze, bang, blow. The pistons deep inside the engine pump like the legs of a cyclist. As the piston falls within its chamber, it sucks in a mixture of air and fuel, and then squeezes it so hard that the fiery cocktail is compressed to a tenth of its original volume. The heat of this molecular crush alone is enough to ignite diesel. With petrol, a spark is introduced, creating an explosion that bangs the piston down again and into its next cycle where the exhaust gases are blown out.
Pressing the ‘accelerator’ introduces more fuel and power to the system, so the pistons revolve faster. They report their rate of progress with a rising note and rumble, and via the needle within the oft-ignored tachometer, or rev counter, next to the speedo.
Somewhere between idle and maximum revs where the needle ventures into the red on the tacho, the engine develops its peak turning force or ‘torque’. You wish that sweet spot would last for ever as all that rotational power begs to be harnessed in some way. The clutch has the means to do this by joining the engine to the gearbox, which in turn connects to the wheels.
The clutch manages the speed differential between the engine and gearbox by holding the gear in one hand and harnessing the engine’s spinning flywheel with a high-friction pressure plate in the other.
Think of the flywheel as a spinning merry-go-round and your feet as the clutch plate when you climb aboard. When your feet land on the ride, your speeds suddenly match, and round you go. As you release the clutch pedal with a gear engaged, the clutch plate rubs on the flywheel and begins turning until their speeds match. As the clutch plate turns it delivers drive to the gear and through to the wheels. Forward motion commences. When the clutch is fully released the car’s road speed matches the engine speed for that gear.
The gearbox contains various gears for different ranges of road speed from zero all the way up to the car’s maximum, enabling the engine to unleash its finest torque again and again as we accelerate from one gear to the next.
Imagine the gears are athletes running a relay race with different physiques and specialist skills. First gear has short, powerful legs like a weightlifter, delivering maximum force to get the car moving from a standing start. As it speeds up, our short, fat, hairy man in Lycra reaches his top speed and runs out of steam. We need to pass the baton to a new gear with longer legs for faster running, and so on, until we reach top gear with the likes of Usain Bolt. Handing the baton back to a slower runner when the vehicle is still sprinting at high speed forces short legs to spin much faster than they were designed for. The engine screams, and the tacho sees red.
When the gear exceeds its speed range in this way, it creates an engine speed so fast the pistons try to relieve themselves by exploding out of their housing. So, you use the gears that marry engine revolutions with road speed to avoid a meltdown.
All the pounding metal and churning fluid within the engine and gearbox create internal resistance by friction. The faster the engine is turning, the greater the resistance. When you hit the road there are other frictional forces where the tyres meet the road and the exterior encounters resistance from the air. These natural forces want to slow the car, so by lifting off the accelerator pedal and cutting power to the engine, you decelerate. So it’s time to adopt this pedal’s real name: the throttle, so-called because it can be used to accelerate as well as decelerate by choking the engine.
Last, but by no means least, there is the brake pedal with its near-infinite range of pressure adjustment. This is the primary device for slowing the car. A mere brush compresses the fluid underfoot, instantly squeezing four sets of clamps onto their respective brake discs, themselves attached to the rotating wheels. Friction on the discs drags speed from the car and transmits weight to the front tyres.
It sounds like a lot to take in at first, but the engineering quickly synchronizes with the human body to make the process as thought-free as breathing. Being clumsy with any element of the control process is no bad thing; the only mistake would be not to admit it.
For me, it was the clutch that took longer to master. I was so insensitive to its powers that passengers were handed neck braces, but a winter racing series forced me to change. Corners at 100mph became ice rinks where every gear change could break traction. I developed my left foot accordingly and in years to come this would prove vital.
I was forced to relearn the basics when I drove a Skoda with a helicopter balanced on the roof for Top Gear. Any sudden movements would have resulted in a beheading and expensively broken helicopter.
A rooftop helicopter is an expensive training device, but what you can do is plant an imaginary glass of water on the dashboard and drive in such a way that you don’t spill a single drop. If you can avoid getting wet, you will benefit in three ways:
- You are highly unlikely to be involved in a crash.
- You will save up to 25 per cent on your fuel bill.
- You will be a better driver, on the road and the race track.