After a successful weekend in Melbourne our attentions turn very quickly to Sepang. The 5.543km circuit is a challenge for the engine as a high percentage of the lap is spent at full throttle, plus there are two long straights of just under a kilometre each.
On each of these straights the engine is at full throttle for over 10 seconds, thus requiring strong acceleration and top speed. The two straights however run in opposing directions, which we need to take into account when selecting seventh gear - if the wind is blowing down one straight, the acceleration can be compromised on the other one if the gear ratios are not correct.
There are also tight mid to low speed corners so the engine needs to be responsive on the apex and exit of turns. In particular, the first corner complex requires good stability under braking and response on pick-up as it leads onto a long, curved straight. Engineers will try to deliver the correct amount of overrun support here to help the driver on turn in so this exit is not compromised.
Of course the main characteristic of Sepang is the high ambient humidity. Even if the rain stays away, the high water content in the air displaces the oxygen available to burn, which slows the combustion process and reduces engine power output. If it rains – as we’ve seen every year so far – the challenge is to set the parameters to reduce power loss while still providing enough grip. Renault engineers will set the pedal maps appropriately for wet conditions to help the driver better modulate the torque application and will then monitor the on-car torque sensor to ensure the engine is always providing the torque requested. This is particularly important in the quick turns, and particularly the back section from turns 9 to 13.
Allied to the difficulty of the track, there is the challenge of how to manage the engine pool at the start of the season. Basically in Melbourne, we introduce the first engine with the aim to use it the entire weekend. Coming into Sepang, there are two options: either keep the first engine for the second consecutive entire weekend and have an engine with up to 1,600km at the end of the Sepang race, or introduce a second (fresh) engine for Saturday and Sunday in Sepang to avoid high mileage at the end of the race here. The second option gives us more flexibility to use the first engine as a Friday engine for longer. We know there will be mix of strategies at Sepang and this will give a bit of information on how teams evaluate this topic.