Brazilian Grand Prix: An engine’s perspective

The 2010 Formula One World Championship edges closer to its exciting conclusion with the penultimate round of the season, the Brazilian Grand Prix, taking place at the Interlagos Circuit this weekend.

Brazilian Grand Prix: An Engine’s Perspective

The Interlagos circuit, officially named after the late Carlos Pace, is all about altitude. At circa 930mbar ambient pressure, it is almost 10% lower than the conditions experienced in Korea. This reduces the density of the air going into the engine and, in theory, the power output by the same amount. Whilst this may sound quite dramatic, from a calibration perspective the changes are very straightforward. Some fuel needs to be removed to maintain a constant air-to-fuel ratio, which is carried out in an automated process at every event regardless.

The big test for the engine at Sao Paolo is on the exit of turn 12. The television images do not do justice to the very steep climb at the exit of this corner, which continues through turns 13 and 14, all taken flat in the dry. Coupled with the power reduction, this makes the climb seem all the longer for the drivers. Shift-lights will be fine-tuned to the gradients and gear ratios in order to ensure that the maximum performance is extracted from the engine. Working in an engine’s favour, drag also reduces at altitude, which helps to combat the associated power loss. However so does down-force, meaning the drivers will ultimately have less grip at their disposal. Fortunately, all engine manufacturers are subject to the same laws of physics, so it will be a shared suffering!

Another point to note is that the cooling efficiencies also drop-off with the lower ambient density. Whilst the conditions are not as dramatic as those experienced by WRC cars, which endure the rarefied atmosphere of 2140 metres above sea level on the El Condor stage of Rally Argentina, any deficit is partly offset by the lower power output, as less heat is being rejected to the oil and water. One final, relatively positive, side-effect of the altitude is that the internal components of the engine that are loaded due to combustion will have an easier time in Brazil due the reduced cylinder pressures that accompany the low ambient pressures.

Fast Fact

Giancarlo Fisichella memorably won the curtailed 2003 Brazilian Grand Prix in a Cosworth-powered Jordan. Heavy rain led to one of the most chaotic races in Formula One history which was brought to a premature end after 55 laps with the win being initially and incorrectly handed to Kimi Raikkonen. As a result the Brazilian Grand Prix drivers and constructors trophies were presented to Fisichella and the team at the San Marino GP two weeks later.

This Weekend in History... 7 November 1993

Ayrton Senna won the Australian Grand Prix in Adelaide in a McLaren-Ford. It was his fifth win of the 1993 season and secured him second place in the drivers’ championship.