How Mexico is forcing teams to innovate

The Hermann Tilke-reworked Mexico City circuit's high altitude, long straight and low-grip surface have forced Formula 1 teams to focus not on bringing upgrades this weekend, but on adapting their cars to a circuit with unusual and challenging requirements.

At 2240 metres above sea level, the air is thinner than at any other race, which affects engine power, cooling and downforce.

With less oxygen the engines need to work harder to create power, something that is possible with a turbocharged engine as the turbo could simply be pushed harder to create more boost.

However the regulations limit the MGU-H, which is in line with the turbo's shaft, to 125,000 RPM. Many teams already are near this limit and it's not possible to exceed the RPM cap, so engine power may also be limited.

The thinner air also makes radiator cores less effective, which has a further impact on power as well as reliability. To keep the power unit cooled, the radiator outlets need to be opened up and the duct work optimised.

One solution taken by several teams is to adjust the duct work leading from the roll hoop.

Often teams take a feed off the airbox to the gearbox or hydraulic oil cooler. In normal conditions this set-up is effective as cooling flow is increased when off the throttle.

In the rarefied atmosphere of Mexico, maximising airbox flow is more important, so the branch duct is closed off and a new dedicated feed is directed to the cooler from extra 'ear' inlets around the rollhoop. Though it has a small aero penalty, this set-up maximises power and cooling.

Downforce and drag are also reduced due to the thin air, so teams need to run much larger wings to offset the loss from the altitude.

Therefore despite the long straight most teams are running near Monaco levels of wing simply to create Monza levels of downforce.

Even with the power penalty the long straight and reduced drag means that the cars are hitting even higher top speeds than at Monza.

This also creates issues with braking from those high speeds, with many teams underestimating the braking demands and the problem of cooling them with the thin air.

MERCEDES

A Mexican-spec cooling package was tested on Nico Rosberg's car in the United States and has been applied to both cars this weekend.

Closer inspection shows the cooler fed by the ear inlets is most likely for the gearbox oil, relocated from the airbox to the back of the car.

In first free practice Rosberg's incendiary brake problem was caused by the team underestimating the brake duct size and overheating the brakes. Larger ducts have since been fitted to resolve the issue.

FERRARI

No obvious cooling changes have been made to the Ferrari aside from an oversized cooling outlet, which shows the louvered radiator set-up is very effective at cooling the car's power unit.

At the rear, the large wing set-up was aided by a new Y100 monkey seat winglet. This winglet was tested, but not raced, in Singapore. The wing is a littler larger with deeper endplates.

A small diffuser tweak was also run that complements the diffuser trailing edge change raced at Austin.

FORCE INDIA

The British-based, Indian-brand team adds another multinational element by considering Mexico as a home race by dint of driver Sergio Perez's presence.

With big expectations here, Force India chose to develop a new rear wing, which makes its debut at this race and is paired with the new front wing brought to Austin.

Like many of Force India's updates run since its mid-season upgrade, it was both developed in the Toyota windtunnel and bears a resemblance to Red Bull's wing designs.

As only the two wing elements have changed and not the endplate, the leading edge of the wing is not as stepped as before and the flap size has subtly changed too.

One detail change is the outer 10mm of the wing profile. This area is not subject to the two element wing restriction, so many teams break up this area into multiple profiles.

This is useful as the intersection of the wing and endplate is 90-degrees and airflow along the join is hard to keep clean. Having more profiles in this narrow area keeps the airflow attached and maintains the efficiency of the wing.

TORO ROSSO/SAUBER

Like Mercedes, Toro Rosso and Sauber have added ear inlets to their rollhoops to feed coolers at the back of their cars.

MANOR

F1's smallest team has made another rare technical update with the introduction of new front brake ducts.

Whereas the old ducts had a stepped leading edge reaching forwards around the tyre's inner sidewall, the new ducts have a simpler, straighter edge.

The inner inlets appear to be arranged the same, but the flatter profile now allows a vane to be added to the duct to aid airflow around the wheel's inner face.