Brasil - Race Engineers's Notes

Interlagos and its challenges

Round 17 of the FIA Formula 1 Championship takes us to Sao Paulo, Brasil.

This old school circuit is Formula 1 jewel. Its similarities to a gritty karting track are quite striking, which is probably why most drivers adore this circuit. History has witnessed some iconic moments at this special place such as: Senna’s heroic first win at home in ’91 and Hamilton’s ’08 final corner Championship winner.

There is only one ‘real’ straight with the rest of the circuit comprising of curves and corners, all of which vary in magnitude. 

The circuit has been renovated for 2014 with a new pit lane entrance, and more importantly with a new resurfacing. Pirelli also re-nominated their tyres to help ensure suitable degradation throughout the race.

Aero Characteristics of Circuit

Sector One starts with the Senna S curve, where the tricky turn in phase may claim more victims than usual because of the new, smooth tarmac. Turn three will demand medium downforce as the cars fight to stay on line after being initially disturbed by the tough Senna S.
The following (and only true) straight of the circuit follows, where Sector 1 ends at the braking zone. This DRS straight is the first real opportunity to overtake after the lunging opportunity back at T1.

Sector Two progresses into a series of highly challenging tight corners. Entry speeds are tremendous considering how constrictive and street like the corners are. Once again, high downforce levels are required to keep the cars stable as they enter S2’s corners.
The curvaceous nature of this circuit means that the car is under lateral loads during the braking phase (Such as T8 and T10). This results in increased levels of instability, which manifests itself in lots of oversteer spins.

Sector Three starts at T12, the one corner of this sector which requires braking. T13/14/15 are basically all on the pit straight and don’t require any input changes except for steering. It is no doubt that they’ll be flat out, even without the blown diffusers.

Sector Two is the dominating sector of this circuit and therefore the car needs to be set up to be quickest around here. The corners at Sao Paolo aren’t particularly high speed and therefore a very high downforce spec is not especially required. Any excess downforce will not result in quicker cornering speeds but they will result in enhanced drag levels on the straights.

Tyres & Strategy (Wear, options)

Prime – Medium (WHITE)
Option – Soft (YELLOW)

Interlagos’ recent resurfacing will reduce degradation massively. Just as in Sochi, the tarmac will not yet have had chance to expose its ‘base’ layer, this means that the tyres will not have anything abrasive enough to cause substantial degradation. We will have to see over the weekend whether Pirelli nominated a suitable pair of tyres.
It is a little bit of an unknown to the engineers as to how the tyres will behave, but it is nothing that can’t be realised from the practice sessions.

As I mentioned last week, two of Ricciardo’s wins have been on a soft/medium combination and it would be worth keeping an eye on him! Ricciardo comfortably secured the final podium position which confirmed my predictions.

Mechanical Set Up

Sector two is the main decider at Interlagos. Stability is key as the circuit induces heavy instabilities especially at corner entry.

A higher than usual roll centre is most likely required to allow the cars to absorb any lateral instabilities which will help the car bite and roll at turn in.

It is worth noting that a stiff setup will be extremely poor when combined with the resurfacing. Four wheel sliding and endless levels of oversteer will ensue with a stiff chassis and suspension.

Interlagos requires a very good chassis design because it relies upon mechanical set up quite heavily. The m

edium speeds of the circuit means that the cars can’t generate the highest levels of downforce, this means that the cars have to extract grip from somewhere else, the mechanical set up.

Thanks for reading, I hope you enjoyed it! (Apologies for it being late)

Ali