Preview: Bahrain GP
Formula One heads straight from Shanghai in China to the Middle East this week with Round Four, the Bahrain Grand Prix, taking place at the Bahrain International Circuit in Sakhir on Sunday 21 April.
The Bahrain International Circuit sees the cars exceed 300 km/h on four separate occasions. 11 of the circuit's 15 corners are taken at 200 km/h or less, in fourth gear or lower. There are eight braking events around the lap, with five of them classed as heavy braking zones.
Pirelli’s hard [orange] and medium [white] compounds are nominated here. Despite the circuit’s desert domain, the track is not as sandy as you may expect due to the circuit’s impressive track cleaner! The asphalt is has a high level of abrasion which gives good grip, but can lead to high tyre degradation. On top of that Bahrain is one of the most demanding tracks of the year in terms of longitudinal energy going into the tyres: especially under braking in turns one and 14, and traction in turn 10.
Track highlights
Turn 1 The first corner is actually very tight as the driver brakes down from over 330kph to just over 60kph. Delivering the correct engine braking support to square up the rear of the car without creating too much ‘push’ is the aim as the driver will need a stable car under braking but must still be able to turn in. Engineers will do this by tweaking the engine maps.
Turn 10 The entry to turn 10 is difficult. You need to be in the correct track position after turn 9 and the un-weighted inside wheel can easily lock. Sufficient speed needs to be carried on entry, but it’s easy to out-brake yourself here. There is a long serrated kerb at the exit to turn 10 which is best avoided.
Turns 11 & 12 After a slow exit from Turn 11 the track goes uphill into Turn 12 so as well rapidly switching direction, the car is also climbing. This therefore puts the oil system under pressure as the fluids in the system move from side to side very quickly but are also squashed down in the tank as the altitude increases.
Turns 14 & 15 The driver must get the exit of Turn 14 completely right as it falls slightly off camber as it enters Turn 15; running wide will compromise the acceleration down the long straight. Getting correct gear ratios helps in this respect, but finding the right balance is never easy as the circuit has a variety of corner speeds. Finding the sweet spot in the engine is therefore tricky, particularly on different fuel levels and pending DRS and KERS release patterns.
Car setup
Front wing Front wing settings are optimised around turns six and seven.
Rear wing Relatively high levels of downforce are required for Bahrain, so the car runs with a lot of rear wing. Not to Monaco levels, but comparable amounts to Albert Park and Malaysia. High temperatures mean less dense and aerodynamically effective air to cleave.
Suspension There are reasonable traction demands here, so the suspension needs to sufficiently compliant for these requirements. Traction demands from the lower speed corners mean a focus on enabling maximum usage of the mechanical grip from the tyres. Kerbs are used in turn two in order to maximise straightline speed before turn three. The long kerb at the exit of turn 10 is generally avoided because its harshness can hurt traction.
Brakes Bahrain represents the first proper test of the season for braking systems. Long straights lead into slow corners, meaning brake temperatures and wear levels need close monitoring.
Engine Sakhir sits in the middle of the table for the demands it puts on the engine, with drivers at full throttle for between 55 and 60% of the lap. With a variety of speed corners, medium length straights and relatively long periods of time at full throttle, it is more external factors that affect preparation rather than the circuit itself.
The high ambient temperatures have an obvious effect on cooling as the heat cannot dissipate from the engine efficiently. Where possible we try to avoid opening the bodywork as it has an adverse influence on the aerodynamic performance of the car. Instead, we try to get the lowest heat rejection into the car cooling system by operating the engine at higher water and oil temperatures, which eventually get the heat rejection down. However this means that the internal engine parts will run at a higher temperature, which needs careful monitoring.
Additionally when air temperature increases, the engine has to be tuned differently as the speed of sound also increases proportionally. This means the sound pressure waves created by the engine arrive at the inlet valve at a different time so the length of the trumpets (which regulate the intake of air into the engine via the airbox) need to be increased as well for perfect engine tuning – recreating a power curve that is equal to ‘normal’ ambient conditions.
Quick facts
Number of corners: 15 (6 left & 9 right)
Maximum speed (no DRS): 315 km/h
Minimum speed: 65 km/h
Corners below 100 km/h (qualifying): 3 (T1, 8, 10)
Corners above 250 km/h (qualifying): 3 (T5, 9, 12)
Average lap speed (qualifying): 208 km/h
Distance to from pole to apex of T1: 400 m
Braking events: 8, 5 heavy
Pit-lane length under speed-limit control: 480 m
Pit-lane time at 60 km/h: 28.8s
Pit-lane time at 100 km/h: 17.3s
Full throttle per lap (% lap distance): 70%
Full throttle per lap (% lap time): 59%
Longest period at full throttle: 13.5s
Average gear changes per race lap: 52 (2964/race)
Braking energy: medium
Fuel consumption per lap (kg): 2.5
Fuel consumption (l/100km): 66
