Preview: Indian GP
This weekend will see F1 compete in India at the Buddh International Circuit, likely the host of the championship decider of the season as Sebastian Vettel edges ever closer to his fourth consecutive World Championship
The Buddh circuit is yet another track designed by Hermann Tilke, and is a circuit that is very similar to the Korean Grand Prix circuit. It similarly features two very long straights and a twisty section. The circuit's main point of attraction is the long right hand turn 10 and turn 11, effectively making for a large loop of more than 180 degrees.
The circuit is however one of the more interesting circuits on the calendar for engine engineers as there are many separate challenges over the course of one lap. There are long periods of wide open throttle, such as the long back straight, which require good top end power, but equally there are some tricky complexes such as turn 1 and the final sector. Additionally we encounter several long, radial turns where delivering sustained torque in the medium rev range is required. Balancing out the need for high top end power with the requirements for good medium and low speed driveability is always a tricky balance to find.
Despite interest from sponsors and the Indian people, political issues have hampered the circuit a bit. This led to the event being dropped from the 2014 calendar altogether to see a return early in the 2015 season.
Circuit highlights
Pit Lane One of the longest in Formula 1 at over 600 metres, with a resultant influence on pit stop strategy.
Back straight (between Turns 3 and 4)
The Buddh circuit features three long straights; the pit straight, the long run between turns 3 and 4 and the shorter spurt from there down to turn 5. The longest straight is the back straight, a huge 1.2km, with the engine running at wide open throttle for over 15secs. Interestingly this straight also features an altitude change with the track going downhill to the midway point of the straight before then climbing back up. The gradient changes will have an effect on gearing, which will need to take into account the dip and crest.
Arriving at the end of the longest straight, Turn 4 is another wide corner which should assist with overtaking. It’s also the heaviest braking point on the circuit with cars going from 320 down to 90km/h in just 140 metres; another aspect which should aid passing manoeuvres.
Turns 8 – 9 This right / left duo requires quick change of direction from the car.
Turns 10 – 11 The second part of the track is much twistier, shifting the emphasis from outright power to engine driveability. Turns 10 and 11, a radial turn with a profile similar to the Spoon Curve in Japan, is one of the most challenging. The drivers ‘play’ with the pedal over a relatively prolonged period as they attempt to find the limit of the car. This sustained period of lateral G will also test the engine’s oil and fuel systems to their limits. Through this long curve, understeer is the enemy and car setup is focused on countering this.
Turns 13 – 14 Another section requiring good change of direction from the car, which needs to be stiff to ensure receptive response.
Car setup
Front Wing Front wing downforce levels must be sufficient to eradicate understeer; particularly through the high-speed Turn 10-11 combination where it would cost a lot of lap time.
Rear Wing The Buddh International Circuit is comparable to a Suzuka or Barcelona level of downforce; similar to that used in Korea, which is a couple of steps away from maximum load.
Suspension There are no significant bumps or kerbs that require special attention, but good change of direction through the medium speed corners is required, so suspension would tend to be at the stiffer end of the range.
Brakes There are significant braking demands at Turns 1 / 4 / 5, but overall it isn’t a hard circuit for brakes. There is a long straight for the brakes to cool before Turn 4 and they also will not be unduly stressed heading into Turn 1.
Engine The first part of the circuit requires good top speed and power, since 75% of this sector consists of straights. The second part of the track is twistier and requires a more driveable and responsive engine. The resultant engine requirements will be similar to Korea in this respect. Dust and grit from the surface can also be ingested into the airbox, so filters will be regularly inspected to avoid blockages.
Tyres Pirelli has allocated the medium and soft tyres this time around. Previously the hard tyre was brought with the soft, presenting a challenge for the team.
Quick facts
Circuit length: 5.125 km
Race laps: 60
Race distance: 307.249 km
Lap record: 1:27.249 (VET, 11)
Number of corners: 16 (7 left, 9 right)
Maximum speed (no DRS): 315 km/h
Minimum speed: 70 km/h
FIA corners below 100 km/h: 3
FIA corners above 250 km/h: 1
Average lap speed (qualifying): 212 km/h
Distance from pole to apex of T1: 230 m
Braking events: 8 (4 heavy)
Pit-lane length under speed-limit control: 414m
Pit-lane time at 80 km/h: 18.6s
Full throttle per lap (% lap distance): 63%
Full throttle per lap (% lap time): 53%
Longest period at full throttle: 14.2s
Average gear changes per race lap: 58 (3480/race)
Braking energy (1 - low, 3 - high): 2
