How Altitude Affects a Formula 1 Car

One word always features whenever Formula 1 visits Mexico City: Altitude.

At 2,240 metres above sea level, the Autódromo Hermanos Rodríguez is by far the highest circuit on the F1 calendar.

That should be no surprise, considering Mexico City is one of the highest altitude cities in the world and sits in ninth place on the capital city altitude list.

To put the circuit in comparison for F1, the highest altitude we visit, aside from our annual trip to Mexico, is around 780 m when the sport heads to Sao Paulo.

It's an extreme height to operate at and affects all aspects of F1 cars. Here's what we need to prepare for when racing at altitude.

F1 cars can corner at such breathtaking speeds because of the aerodynamic engineering that generates downforce so the tyres can produce more grip.

Just as an aeroplane's wings force the oncoming air to create lift and push the plane into the sky, an F1 car takes that concept and turns it upside down.

You'll spot the aerodynamics most clearly at the rear wing, where the teams use varying angles to generate the ideal amount of downforce for the circuit they're racing at.

Typically, a driver only wants downforce when cornering as it will slow the car down when driving on a straight when they'd like as little drag as possible.

High-altitude racing reduces the amount of downforce and drag generated because of the reduced air density.

Aerodynamics require air particles to work, so with the thinner air at altitude, there are fewer particles for the car's aero to push against.

F1 teams use high-downforce aerodynamic configurations usually reserved for tight and twisty tracks like Monaco when they race at Mexico City.

Yet, even this high-angle wing can produce less downforce than the low-downforce setup reserved for Monza's high-speed straights.

The result is the needle pushing up the speedometer irrespective of the downforce setup, with Valtteri Bottas setting an F1 Grand Prix speed record of 372.5 km/h (231.4 mph) in the Williams Racing FW38 in the 2016 Mexican GP.

Inversely, there is reduced grip available in high-speed corners, hence the high-downforce rear wings you'll spot around Mexico City, which help the drivers turn but without the penalty of drag.

Equally, DRS is less powerful here than at other circuits, as the rear wing isn't generating anywhere near as much drag down the straights.

While aerodynamic changes might seem an obvious issue for long-time fans who think about racing at altitude, some might overlook cooling the car.

F1 cars use the incoming air to cool down the many components that come together to create such advanced machinery.

With so much thinner air in Mexico City, fewer air particles are hitting the car than at equivalent speeds elsewhere on the calendar.

Reduced air pressure means that elements like tyres, brakes, and power units don't get as much air flowing over or through them and cannot sufficiently cool down.

Subsequently, teams will open the bodywork and brake ducts to capture more air in an effort to compensate for the altitude.

This change would ordinarily increase the drag on the car, slowing it too much down straights and leaving the drivers at a disadvantage.

When racing at altitude, however, the drag is sufficiently reduced so it's less impactful, allowing for wider air intakes for the power units, brakes, and other components that require cooling.

One component's performance that is surprisingly unaffected by the heights of Mexico City is the modern-day power unit.

Engine output will usually be reduced by around 1% per every 100 m increase in altitude above sea level.

For example, a standard internal combustion engine will be approximately 22% less effective at Mexico City's 2,240 m altitude than at the mostly sea level Yas Marina Circuit in Abu Dhabi.

However, more air is pumped into an F1 car's power unit already, thanks to the turbocharger part of the power unit.

Although there is a reduction in power output, it is less than what a standard car's engine suffers from because the turbo is already pushing more air into the power unit, plus there is less aerodynamic drag that the engine must drive against.

The downside is that the turbo must run harder and, therefore, hotter as it pumps more air into the power unit, hence the additional cooling requirements.

One final part of racing performance that altitude affects isn't anything that the designers or engineers can mitigate against.

Humans will generally operate worse at higher altitudes and the thinner air that goes along with great heights.

The drivers are the most visible example of this, seeing as they're the ones pushing the limits for 300 km of racing, but altitude affects the whole team.

Fatigue will happen quicker at higher heights, so strategy calls, pit stops, repairs, and car setup changes might become slower than when racing at sea level.

Sleeping isn't as easy at altitude, either, as less oxygen affects the brain and results in more frequent awakenings and more difficulty falling asleep in the first place.

Fatigued and sleep-deprived drivers and team personnel are more likely to make mistakes, further increasing the difficulty of competing in an already challenging sport.

In some more extreme cases, altitude sickness can impact people who acclimatised to the 2 km height of Mexico City, too.