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.
Italian Grand Prix engine facts and figures:
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. Sebastian Vettel, Red Bull Racing
Monza is one of the greatest engine tracks on the calendar and winning here is a great feeling. You’re flat out on the throttle for almost the entire lap so you need the engine to be powerful at the top end as any gain is worth a considerable amount of time. With the slower chicanes the gear ratios need to be correctly calibrated to get the most effective acceleration so it’s not an easy circuit. We won last year with the Renault engine so we know how to get it right, I hope we can get it right again this year.
Rémi Taffin, Renault Sport F1 head of track operations
Monza is actually comparable to a high speed Oval in the States, with an average speed of over 250kph. The RS27 will be at full throttle for almost 20secs in two sections of the track: to put this into perspective, a light aircraft could take off in that time! Only the grip generated from the wings stop the cars from lifting, generating huge pressures on both the car and the driver.
The engines are also put under enormous stress, being operated to their maximum level for over 75% of the lap. We therefore introduce some new engines for this event, despite having used new units at the last event in Spa-Francorchamps.
Although top speed and outright power are the focus, we work very carefully to calibrate the gears to give good acceleration to get to this top speed. This involves using longer gear ratios than usual.
Even though the engine is running at full throttle, fuel consumption is actually one of the lowest of the year and the race starting fuel load is the second lowest of the season. Only Monaco has a lower starting load, but this is due to the very short distance of this Grand Prix. Surprisingly for some, Monza is actually the most fuel efficient of the year as the engine is working at a largely consistent level and the car is running a highly efficient downforce package. It’s comparable to driving on a motorway and driving around town in a road car; fuel consumption is less when driving as a stable level (even when driving quickly) than stop-starting and going through the gears.
KERS is also an area we concentrate on as getting a boost down the straights will help overtaking possibilities, however recovering the energy used to then deploy the KERS is not easy. There are only two real braking zones so it’s a challenge to keep the battery topped up throughout the lap.
Source: Renault Sport