Interlagos sits in the upper bracket for ICE difficulty. The circuit may be short, but the long, uphill pit straight takes up a considerable percentage of the lap.
The driver will be at full pedal travel for around 15secs, around 25% distance, or 20% of the overall lap time. Good acceleration is critical here as Turn 1 is an overtaking opportunity, but the engines will be straining on the edge of their power as the elevation change is just shy of 40m from the exit of Turn 12 to the braking point of Turn 1.
From the exit of Turn 2 to the entry for Turn 6 the driver is at full throttle for a further 17 secs, with just a dab on the brakes through Turn 4. The track goes downhill through the Curva del Sol, with the car gaining further momentum, but then climbs back up to the Ferradura. To maintain the speed while dealing with the change of gradient, the internals of the engine will be heavily loaded.
From Turn 7 to 12 the circuit gets very twisty, which loads and unloads the ICE in very quick sequence. Coming after such a sustained period of full throttle, it’s hard on the ICE, but difficult for engineers to find the right compromise in mappings between good top speed and effective acceleration.
Interlagos is the bumpiest permanent track of the year due to the intense weather conditions, relative lack of use and location. The large bumps can make the car temporarily ‘take off’. Even if it’s just for a second, with no load running through the wheels the engine suddenly hits the rev limiter, which puts the internal parts under huge stress.
Interlagos sits 800m above sea level. Until the Mexican GP it was the highest race of the year by a long way, but now seems low by comparison to the giddy heights of Mexico City ! The turbo will be spinning at a much higher speed to generate the same power as a sea level event, rotating at very close to its maximum, but having worked reliably at the 2,200m Mexican GP, Interlagos is no longer the sternest test of the year.
Monitoring the turbo is nevertheless one of the main challenges of the weekend for the engineers and after each session it will be thoroughly checked over for any mechanical wear. It will also be checked for ingested dust or sand, which can often be a problem in the gritty Sao Paulo atmosphere.
While the ICE and turbo are under a lot of pressure, the other parts of the PU are not too stressed at Interlagos. The MGU-K can recover energy through the short corners, notably Turn 1, 8 and 10. The hardest test for the K presents itself in qualifying. To open the fast lap you must optimize the top speed at the end of the long final straight on the out lap by using the K for additional power boost but starting too low on electrical energy for the qualifying lap can compromise the lap time.
Turn 1 is the hardest stop of the circuit as the cars arrive at over 330kph and drop to just 110kph for the entrance. The energy going through the brakes at this point is enormous and will recharge the battery ready for deployment on the straight to the ICE from Turn 2 to 4.
Due to the long periods of full throttle, the MGU-H has ample opportunity to recover lost exhaust energy. However, energy recovery is not necessarily critical as fuel consumption is relatively low due to the high altitude and lower air density.
Did you know…from Total
Developed at the Total Fuel Research Centre in Solaize, additives incorporated in the F1 fuels are multi-functional, performing functions including anti-corrosion, anti-oxidation, detergents, lubrication, combustion optimization and improving the octane. These additives can reduce friction between some mechanical parts and avoid residual deposits on injectors or in the combustion chamber.