There’s no venue on the Formula One calendar quite like the Autódromo Hermanos Rodríguez.
The altitude has a direct impact on car performance
But it’s not just the raucous crowd that makes the Mexico Grand Prix special. Situated at 2,200m (7,218ft) above sea level, the Mexico City circuit is the highest on the current F1 calendar - and that altitude has a direct impact on car performance, presenting a unique challenge for all of the teams and engine suppliers.
Brazil's Interlagos previously held the accolade of being the highest altitude location on the Grand Prix tour – the undulating track sitting at an average of approximately 800m above sea level. But Mexico smashes that figure. An altitude of 2,200m comes with a significantly reduced ambient air pressure, which in turn results in a reduction in air density. With only 78% of the oxygen level available at sea level, the air-limited Internal Combustion Engine (ICE) produces less power.
Including the epic 1.2km run down the start-finish straight
To make up for this loss of power, the Turbocharger has to rotate faster, working extra hard to force air into the Power Unit to compensate for the lack of oxygen entering the ICE. This puts even greater emphasis on the durability and efficiency of the Turbo. Remarkably, the 2017 Power Unit can recover the majority of the lost performance via this method. However, in pushing to compensate for the thin air, the compressor is worked harder, which pushes up temperatures. With higher compressor duties, more heat is passed into the air and water systems. The knock-on is higher stress on the mechanical elements inside the Power Unit – and all this around a circuit layout that’s naturally high duty on the engine, including the epic 1.2km run down the start-finish straight at full throttle.
Managing temperatures of the PU will be a challenge in Mexico, hitting the higher end of what’s known as the ‘cooling curve’. Lower air density makes the cars tougher to cool, increasing the strain on air-dependent systems such as the radiators, brakes, gearbox and Power Unit. This means bodywork packages needs to be opened up, with larger brake ducts fitted and additional air intakes installed. To combat these issues, the team at Mercedes-AMG High Performance Powertrains (HPP), Brixworth, spend a lot of time ahead of the Mexico Grand Prix working through simulations and running the Power Units on the dyno using Mexico-specific atmospheric conditions, in an effort to avoid any nasty surprises. But it’s a tough game, nonetheless.
The F1 fiesta climbs to 7,000ft
Mexico City’s thinner air really does give even the highly-sophisticated modern-day Hybrid Formula One engines a workout. And while there might not be an effective performance change from the lack of air, teams definitely take a hit on the aero front, as they are open up the bodywork for that extra cooling. And, what’s more, the rarefied atmosphere (20% less density vs. sea level) means the cars need to be run at maximum downforce – to the same level as Monaco or Singapore.
Downforce and drag are both proportional to air density. So a 20% reduction in air density results in a 20% reduction in downforce and drag. To put this into perspective, comparing a low-downforce Monza aero package with a high-downforce Budapest package, teams would expect a 10% reduction in downforce and a 15% reduction in drag. Despite the high-downforce setup and bigger wings on display, the cars will be hitting incredible speeds – a peak of 372.5 km/h during Qualifying last year providing clear evidence as such.
Racing in the dizzying heights of Mexico City might be a tough task – but it’s a high-speed, high-skill challenge the drivers and teams will welcome, as the F1 fiesta climbs to 7,000ft!