The Brazilian Grand Prix is often looked on by engineers and strategists in F1 as the biggest uncertainty of the season – it’s a very difficult race to plan for.
The weather often plays a part; last year was a perfect example. It was the championship deciding race, held in tricky wet/dry conditions. When it rains it is very hard to predict how long it will last and how hard it will rain. Then when it stops, there can be dry parts of the circuit and rivers running across other areas. Last year’s race was won by not switching to wet tyres when it rained!
Then there is the set up of the car; the requirements of Sector 2 of the lap, with its slow tight corners are quite at odds with the requirements of Sector 3, which is mainly a long uphill straight. There is a lot of emphasis on maintaining traction in the transition from the driver braking to putting the power down.
Add in tight run-off areas and a high chance of a safety car and you have a race where teams are relieved to get with an outcome in line with their expectations. Things can easily be turned on their head there.
Another unique feature is the altitude of the circuit at just over 800 metres. This means that the atmospheric pressure is almost 10% less than at sea level and this cuts engine power, and as the air is less dense it means that downforce and drag are cut by a similar amount.
It is also the shortest lap of the season in terms of lap time, a quick lap there being under 1m 12 seconds, so the qualifying and racing have an intense quality about them.
It is one of six anti-clockwise circuits on the calendar.
The tyre choice from Pirelli is again very conservative; as last year they have opted for medium and hard compounds, whereas in 2011 they brought soft and medium tyres.
Interlagos – 4.309 kilometres. Race distance – 71 laps = 305.909 kilometres. 15 corners in total. Average speed 210km/h. A classic circuit set in a natural bowl, in a suburb of Sao Paulo.
Aerodynamic setup – Med/High downforce. Top speed 323km/h (with DRS open) 311km/h without.
Full throttle – 61% of the lap time (ave/high). Total fuel needed for race distance – 134 kilos (ave/low). Fuel consumption – 1.9 kg per lap (low)
Brake wear- light. Number of braking events – 6, Time spent braking – 16% of the lap.
Total time needed for a pit stop: 18 seconds
Fuel effect (cost in lap time per 10kg of fuel carried): 0.31 seconds (ave)
The Brazilian Grand Prix is the final round of 19 in the 2013 FIA F1 World Championship.
Last year’s race was won by McLaren’s Jenson Button, with McLaren taking a front row lock out in qualifying.
Red Bull won the race for the previous three years, Mark Webber, who is making his final Grand Prix start, won in 2011 and in 2009, while Sebastian Vettel won in 2010. Felipe Massa won the race for Ferrari in 2006 and 2008, Kimi Raikkonen won the race in 2007, but will not race this year due to back surgery.
Sebastian Vettel has set a new record of eight consecutive wins in a season, if he wins in Brazil he will extend that to nine consecutive wins.
The forecast for this weekend is for temperatures around 30-33 degrees with little chance of rain.
Rain showers are a common occurrence in Sao Paolo at this time of year and many Brazilian Grands Prix have experienced sudden showers over the years and no-one will factor rain out of their planning, just in case..
Likely tyre performance and other considerations
Pirelli tyre choice for Brazil: Medium (white markings) and Hard (Orange markings). This combination has been seen several times including Austin, Spa, Monza and Suzuka.
The choice of medium and hard, rather than the soft and medium of last year, is very conservative by Pirelli and repeats last year’s decision. In 2011, they brought soft tyres to Interlagos and it was a three-stop race for most of the runners.
Pirelli justifies its choice by pointing to the high-energy loadings through the high speed corners. After a difficult year on circuits with high loadings like Silverstone, the Italian company wants a quiet end to the season.
The track does not have a particularly abrasive surface and the energy going into the tyres is largely from the series of left hand corners before the final straight. On top of that, the tyres get plenty of rest on the two long straights and a safety car around one third race distance could change the decision making process.
The limiting factor on this track is the rear tyre, with the stop-start traction events in the series of corners in the middle part of the lap and the last corner onto the uphill final straight. The cars tend to slide quite a bit on the hard tyre and this adds to wear.
Last year the key strategy call was to stay out when rain started to fall in the early stages with the dry tyres on which the race had been started, but few teams were able to do that, as they could not generate enough temperature in the tyres. Jenson Button and Nico Hulkenberg managed it and it set Button up for the win.
Number and likely timing of pit stops
Last year, before the rain came, pre-race strategy indications were that teams would go for a two stop strategy with the first stop around lap 20-25 with a middle stint on a new set of hard tyres and then review performance before deciding whether to switch to used mediums for the last stint or another set of new hards.
The pit lane at Interlagos is quite short and the time needed for a stop is only 15 seconds plus the stationary time, which pushes teams into doing more stops, as the time lost in the pits is minimal compared to the faster lap times on fresh tyres.
So two stops is the likely default strategy this weekend, although if the tyres look durable, then should there be a safety car early on, one or two drivers may be tempted to go for the track position advantage of one stopping. But unlike many F1 venues, overtaking is relatively easy at Interlagos, as the DRS zone is particularly effective, so a quick two stopper will easily be able to come through a one-stopper who is conserving tyres in the final stint.
Chance of a Safety Car
The chances of a Safety Car are high at 63%. The Safety Car has been used in seven of the last ten races. It is often called into action on the first lap, as it’s a short lap with 24 cars charging into tight corners.
This makes the Safety Car an important element to factor into Race Strategy planning and having plenty of different plans is advisable.
Recent start performance
Starts are a critical part of the race and strategy can be badly compromised by a poor start, while good starts can make strategists change their plans in the hope of a good result.
As far as 2013 start performance is concerned drivers have gained (+) or lost (-) places off the start line this season on aggregate as follows. Please note that where a driver has been eliminated on first lap this has been noted and removed from the sample as it skews the table. So this is intended as a guide of trends, rather than a definitive list.
+25 Van der Garde*****
+22 Sutil*** /********* /************
+19 Di Resta
+18 Massa ********
+8 Button ***********
-5 Raikkonen *******
-9 Hamilton **********
-24 Vergne ****
*Webber dropped from second to seventh after a clutch problem in Australia ** Hulkenberg did not start in Australia *** Sutil suffered puncture from contact with Massa in Bahrain ****Vergne retired following collision. *****Van der Garde and Maldonado made contact in Monaco. ******Bianchi started from pit lane in Monaco after stalling *******Raikkonen crashed into Perez at the first corner at Monza ********Massa spun at hairpin in Korea *********Sutil had collision in Korea ********** Hamilton suffered puncture from contact with Vettel in Japan *********** Button had contact with Alonso at hairpin in Abu Dhabi ************ Sutil crashed on the first lap in Austin
Pit Stop League Table
Of course good strategy planning also requires good pit stop execution by the mechanics and there have been some amazing performances; we have seen tyre stops carried out in less than two seconds this year.
The league table below shows order of the pit crews based on their best total time in the pit lane in the recent United States Grand Prix.
Note: In Austin, Red Bull unofficially achieved the fastest pit stop recorded in F1 at 1.923 secs, which was half a second faster than the fastest stop it did in Austin the previous year
1. Red Bull 23.537s
2. Mercedes 23.806s
3. McLaren 23.808s
4. Ferrari 23.817s
5. Lotus 23.876s
6. Sauber 24.030s
7. Toro Rosso 24.226s
8. Marussia 24.293s
9. Force India 24.444s
10. Williams 25.014s
11. Caterham 25.268s
The UBS Strategy Briefing is prepared by JA on F1, with input and data from several F1 teams, from JA on F1 technical adviser Mark Gillan and from Pirelli.