The Italian Grand Prix’s home at the Autodromo di Monza isn’t called the Cathedral of Speed for nothing; over three quarters of the 5.793km lap is spent at full throttle and the maximum speed goes over 330kph up to four times per lap. It’s the ultimate test for an engine’s outright performance and reliability and, as a result, one of the toughest events to get right.
The circuit is ostensibly a racing oval with the long straights broken only by two chicanes. With only two corners, the Lesmos and the Parabolica, delivering good acceleration and top speed is one of the key challenges for Renault Sport F1.
The Renault-engined Red Bull Racing of Sebastian Vettel won the Italian Grand Prix in 2011, the first Renault-engined victory since 1995. Alain Prost scored the first Renault victory in 1981, with René Arnoux taking the next win in 1982. Williams-Renault had three victories in the 90s, with Nigel Mansell winning in 1991 and Damon Hill in 1993 and 1994. Johnny Herbert then won for Benetton-Renault in 1995.
Around Monza F1 cars will be at the highest average speed of the year; very close to the 250kph mark with a top speed peaking at over 340kph down the pit straight just before the first chicane. Dependant on DRS activation and KERS, speeds may even be higher than this at a singular point.
The RS27 will consistently run in the upper end of the rev range (over 16,000rpm) but the challenge is not to hit the rev limiter too early on the straights. This creates the most effective acceleration. Hit the top gear rev limiter too early in the straight and you will lose a lot of time at the end of the straight as you will be stuck at terminal velocity for too long. Calibration of the gear ratios is therefore one of the trickiest of the year.
The consistently high revs put the engine internals under huge stress. Monza is therefore used as the reference for the Renault Sport F1 endurance tests on the dyno at Viry-Châtillon. The engines are run on the dynos for as much as twelve hours on the Monza track simulation to check for reliability and performance in the toughest of conditions.
A high percentage of the lap is spent at full throttle, which increases fuel consumption. This is however counterbalanced by the very low drag. In other words, more fuel is injected into the engine than at any other circuit but since the car is going so much faster the effect is cancelled out. Monza is therefore counted as an ‘average to low’ fuel consumption on kg/km.
Although the straights are the focus of attention, engine engineers must also consider the chicanes where drivers brake down from over 300kph to under 80kph and accelerate back up to over 300kph in under two seconds. Rear stability under braking with good acceleration on exit is important to gaining lap time. Drivers may also cut the kerbs to shorten the lap distance, so it’s important for the engine not to hit the rev limiter through the chicane, which unloads the engine and loses time.
The Parabolica is taken in fourth gear, with the engine at a consistent rev level for 4secs. The driver has to be smooth on the throttle and the engine needs to be correspondingly smooth and not ‘peaky’ — it’s more about rolling into the corner and keeping the momentum going.