2015 Mexican Grand Prix – Tech Briefing
The Autódromo Hermanos Rodríguez in Numbers
Formula 1 returns to Mexico this weekend after a 23 year absence. The 4.304 km track is the second shortest of the season – only Monaco’s street circuit is shorter at 3.340 km. However, the Autódromo Hermanos Rodríguez is almost exactly the same length as the next track to feature on the calendar – the Autódromo Carlos Pace in Interlagos (4.309 km). Consequently, both races are staged over 71 laps.
The start/finish straight is 1.2 km long – and the time spent at full-throttle along this stretch alone is some 14 seconds. By comparison, the main straights at Interlagos and Barcelona are approximately one kilometer long, while Monza is 1.3 km in length. Racing at the Autódromo Hermanos Rodríguez is in a clockwise direction. There are seven left and nine right-hand turns. Drivers will probably likely have to change gear 52 times per lap. Projected top speed on the approach to the first corner is 360 km/h and a lap time of around 1:19.500 is expected.
A Historic Venue, Re-Mastered
The circuit has been changed many times since it was first built in 1962 and has been remodeled once again since Formula One last raced there in 1992. This includes the removal of the infamous Peraltada Corner. The circuit is named after the Rodríguez brothers who were both killed racing – Ricardo at this very corner.
The Peraltada is has been replaced with a series of low speed corners through a stadium to form Sector 3. Sector 1 comprises the long start / finish straight and a shorter straight joined by a handful of 2nd gear corners and both straights have DRS. Sector 2 starts with two corners that are very similar to Turns 1 and 2 in Montréal, followed by a slow double-apex right-hander and a fast section of flowing 5th and 6th gear corners; not dissimilar to the Esses in Sukuza.
The stadium section will be key to overtaking as the DRS detection point is just before Turn 16, which leads out onto the long start / finish straight. This should present a prime overtaking opportunity.
Riding High, Keeping Cool
The highest speed recorded in Mexico is expected to be the fastest of the season, surpassing even the speed trap readings at Monza. However, the circuit configuration demands more downforce than required in Italy, so wing levels are higher. Furthermore, the high altitude (2,285m or 7,500 ft) significantly reduces drag effect on the car, so expect to see speeds reaching up to 365kph on the long start / finish straight with DRS open and the car in qualifying trim. Incredibly, this amounts to a couple of km/h faster than the highest speeds reached in Italy.
Brazil is traditionally regarded as a ‘high-altitude’ circuit that saps engine power. But at a mere 785m or 2,575ft, the altitude effect at Interlagos is far less significant than in Mexico City. The here is higher than the maximum elevation in 24 European countries including the UK, Sweden or Iceland, or halfway to Everest basecamp. However, with the advent of new V6 Hybrid Turbo engines, the impact of air density at three quarters of that at sea level is not as significant as would be with normally aspirated engines – albeit the compressor will be working far harder than usual. Thus, the maintenance of power and the reduction in drag accounts for the expected higher speeds.
However, altitude can have an attritional effect on car cooling, as the rarefied air density reduces cooling effect. Engineers will therefore be focusing on ensuring the car’s Hybrid systems are maintained within target operating temperatures. It is possible that usual reliability rates across the field will be challenged by this unique operating environment
Fuel for Thought…
The dyno cells at Mercedes AMG HPP have the capacity to run at managed atmospheric pressures and extensive Power Unit testing has taken place in Brixworth at the simulated altitude of the Autódromo Hermanos Rodríguez circuit. PETRONAS have contributed extensively to the mapping of fuels and lubricants to ensure that all aspects of the PU are optimized for the conditions, from combustion mapping in the rarefied atmosphere to cooling of key Hybrid systems with PETRONAS Tutela.
Pirelli’s tyre selection for this race is deliberately conservative – nominating the soft and medium compounds in a bid to ensure all eventualities are covered in the absence of any data concerning the aggregate and asphalt blend used on the track surfaces, the profiling of the kerbs or any other factors that will influence tyre performance.
This ‘safe’ approach to tyre nominations generally means tyres will offer more durability than is required, thus providing an operating margin that will generally skew race operations towards a one-stop strategy. This approach was certainly evident when the new tracks in Austin and Sochi joined the calendar.
The tarmac is completely new and has only recently been laid. Despite the best efforts of the organisers, the surfaces will be dirty from all of the recent construction work. How this interacts with the medium and soft tyres remains to be seen…
The Driver Effect
While conservative tyre choices might tend to ‘normalise’ the array of strategy options, the propensity for drivers to adapt to a new circuit tends to be mixed. Drivers typically acclimatize to new tracks at different rates – and while simulators are tending to offset this variability, there is still an observable tendency for the driver effect to have a higher than usual impact on inaugural Grands Prix.
The driver effect is of course most marked early in the race meeting – but after four hours of track time, it is still possible that some variance in learning and mastering the track will be evident. This in turn creates a higher probability for a mixed grid in Mexico and also the potential for additional overtaking in the early stages of the race as cars return to the hierarchy of their underlying pace.