# BMW M4

How a BMW M4 coupé is built and works, from its doors and start button to its six\-cylinder engine, lights and brakes\.

By Aarav Singh

Topic: Machines

[Open the interactive Jig](https://ask.jig.com/j/53aoqkzsLAcn)

## Transcript

### 1. Meet the BMW M4

This is the BMW M4 coupé, a two\-door sports car\. It is 4\.8 metres long but only 1\.39 metres tall, lower than most family cars\. Tap a door or the bonnet to open it, and drag anywhere else to turn the car\.

The huge upright grille is the M4's famous twin kidney\. Its openings feed cooling air to the engine\.

### 2. Open the doors

The long doors swing out on hinges at their front edge\. The side windows have no frames around them\. Inside sit the seats, the dashboard and the steering wheel\.

### 3. Press START

Pressing the start button sends electricity from the battery, which sits in the boot, all the way to the starter motor at the engine\. The starter spins the engine until it fires and runs on its own\. The car gives a shake and puffs out its exhaust\.

The green dashes show the electric current travelling along the battery cable\.

### 4. Lights on

Slim LED headlights light the road ahead, and red tail\-lights show drivers behind where the car is\. Switch them on and watch both ends of the car\.

### 5. Lift the bonnet

The bonnet hinges near the windscreen and lifts from the front\. Underneath sits the engine, placed behind the front wheels to keep the car's weight balanced\.

### 6. Six in a row

Cut open, the engine shows six pistons in one straight line, pumping up and down to turn the crankshaft\. Two turbochargers use the hot exhaust to blow extra air in\. Press the accelerator to rev it\.

The Competition version makes 510 horsepower\. The motion here is slowed down so you can follow it\.

### 7. Brakes get hot

Here the car runs on a rolling road, so the wheels spin while it stays in place\. Brakes squeeze pads onto spinning discs, and that friction turns speed into heat\. Press the brake and watch the discs glow, then slowly cool\.

The brake lights at the back come on as soon as the pedal is pressed\.

### 8. Steer the front wheels

Turning the steering wheel swings the front wheels left or right, while the rear wheels push the car along\. That is why the M4 is called rear\-wheel drive\.