Brazilian GP: A Thrilling Race in Prospect!

Interlagos is a circuit with many faces, combining tight hairpins with one of the longest straights of the season. A true natural track, Interlagos winds over 4.309 km and is renowned for its bumpy surface, although the problem has been partially resolved with new paving applied in recent years. The physical demands of this circuit are even more pronounced as it runs counterclockwise, subjecting drivers, especially their necks, to forces opposite to those they usually encounter. It is possible to overtake on this track, especially at the entrance to turn #1. The setup compromise generally tends to favor top speed on the straight rather than the best possible lap time: this gives drivers the opportunity to overtake… and avoid being overtaken over 71 race laps.

Aerodynamics

The different constraints of Interlagos require almost opposite qualities from the cars. The first and last sectors are mainly composed of long straights, where good top speed is essential to protect one’s position. This means that a fairly low level of aerodynamic downforce is required there. However, the second sector consists of rather slow corners, which demand a high load to provide grip for re-acceleration, braking, and cornering. Balancing these two requirements gives rise to an optimal downforce level aimed at achieving the best possible lap time. However, this optimum must also take into account the other competitors. To defend one’s chances and attempt to overtake in turn 1, speed at the end of the straight is crucial, so downforce must be reduced.

Fernando explains: « It is very important to exit the last corner with a good top speed. This way, you can tackle the final straight, which is uphill, effectively. It’s at the end of this straight that you have the best opportunity to overtake, and if you’re on the right trajectory, you can do so in the first chicane. »

Clarification

Finding a good compromise in this field is difficult, once again due to the opposing characteristics of Interlagos. As with the aerodynamic sector, choices need to be made and priorities set for certain sectors. The most important corner at Interlagos is turn 12, which dictates the top speed along the long uphill main straight. Therefore, we pay great attention to the exit of this turn, even if it can generate a bit of understeer in the tight corners of the second sector. However, what is lost in this situation is far outweighed by the gains made through a good passage in the third sector. The second important parameter to consider is the track surface. Interlagos was traditionally very bumpy, but the new surface laid down recently allows teams to use lower ride heights. The situation could be even better this year. The circuit does not put the brakes under severe stress but does feature three significant deceleration points. The energy required in this area is comparable to Barcelona.

Fernando explains: « The section from turn six to eight is a difficult part of the circuit and reveals the contrasts one finds at Interlagos. Turns six and seven need to be taken as a single long turn, but it is important to be as steady as possible when approaching this curve and to avoid climbing over the curbs. This section is bumpy, which can destabilize the car. You also have to contend with oversteer. Then, after a fast turn, you reach turn number 8, one of the slowest on the circuit. Here, you need to be aggressive with the steering and use the curbs, while also dealing with understeer. »

Tires

Interlagos has few high-speed corners subjecting the tires to high lateral forces. Since the surface is not abrasive, fairly soft tires can be used without issue. Therefore, Bridgestone will bring the medium and extra soft compounds from its 2009 range this weekend.

Engine

The long main straight at Interlagos demands a lot of power, and the longest full-throttle period exceeds 15 seconds. All engines will also need to be adapted to the constraints of altitude since the circuit is situated 800 meters above sea level. The reduced atmospheric pressure leads to a power loss of around 7%. Consequently, the 62% of the lap spent at full throttle corresponds to 56% at sea level. This situation makes life easier for some mechanical components, like pistons. However, other components, such as the crankshaft, remain under significant stress. Progressiveness is also an important factor, especially in the second sector. Drivers use the lowest gears there, with sharp changes of direction and quick actions on the brakes and the accelerator.

According to a statement from the Renault F1 Team