F1 engine manufacturers braced for Mexican GP altitude test

Brazil's Interlagos previously had the highest altitude of the year at an average of approximately 800m above sea level, but in Mexico that figure is closer to 2,200m.

As the altitude increases, the air becomes thinner and has a lower oxygen content, which means less power due to less oxygen being available to burn with the fuel.

"The issue is going to be cooling for sure because you have the same amount of energy coming out of the engine and much less air to cope with that, so it's going to be cooling," said Taffin.

"The other thing is turbo, because to try to maintain the power output you will need to rev the turbo much higher and you will hit limits.

"Obviously we have done a lot of simulation, but we know we are going to be getting something we don't really know."

Taffin said last week that Renault will not run its upgraded engine this weekend because "it's going to be like an unknown area, so going in to that grand prix with the new engine I don't think would be the best thing".

McLaren direction of engineering Matt Morris added: "This track is the highest that we race at and that will put the power unit under pressure.

"The turbo has to compensate for the lack of oxygen entering the ICE, which will put extra emphasis on reliability for all teams."

Williams performance chief Rob Smedley said his team should be in "reasonable shape" to deal with the scenario.

"There are some differences in the way that we need to prepare the engine, especially in terms of energy recirculation," said Smedley.

"All the manufacturers will be looking at that, how you recover energy from the [MGU-]H.

"If you take other races such as Brazil or Austria, I think we will be going down a similar path to what we have done there, it's just a bit more extreme than both those circuits.

"We have sat down and recognise these things some months beforehand and already have plan in place in terms of what we'll be doing both in terms of power unit and chassis to cope with that altitude.

"We should be in reasonable shape."