As part of the 24 Hours of Spa-Francorchamps, Porsche works driver Laurens Vanthoor and Sebastian Golz, Project Manager Porsche 911 GT3 R, describe what it is like to drive at full throttle through the famous Eau Rouge in the Porsche 911 GT3 R.
Exiting the La Source hairpin, Porsche factory driver Laurens Vanthoor plants his foot on the accelerator. The 500+hp 911 GT3 R catapults out of the first corner of the Circuit de Spa-Francorchamps, accelerating rapidly down the 15 per cent decline. After a very fast right-hand kink, the Belgian hugs the white wall, which separates the old pit lane from the circuit and now echoes the sound of the high-revving flat-six. There it looms in the distance: the famous Eau Rouge of Spa-Francorchamps. Flat out or not? “That’s always a tricky question until you dare to do it for the first time,” says Vanthoor with a laugh. Here on his home turf, known in the racing world as the “Ardennes rollercoaster”, he has celebrated a good number of successes.
During the 24 Hours of Spa-Francorchamps on 24/25 October, drivers will face the Eau Rouge challenge every single lap. This corner combination, which is officially known as “Raidillon”, owes its now famous name to a nearby small creek. The high iron-bearing water is tinged red – “Eau Rouge“.
“I don’t know of a comparable passage anywhere. Eau Rouge is unique in the world.”
In the hunt for top qualifying times on fresh tyres and a dry track with just a dash of fuel in the tank, many drivers take the legendary passage flat out. However, the situation in the race is different. The rubber must be handled carefully in order to survive many laps. Over 24 hours, the car will cover a distance of more the 2,500 kilometres. Tipping the scales at more than 1,200 kilos plus driver and fuel, the total weight of the car is significantly higher than in qualifying. Hence, the forces are higher.
“I don’t know of a comparable passage anywhere. Eau Rouge is unique in the world,” explains Sebastian Golz, Project Manager Porsche 911 GT3 R. On the legendary circuit nestled in the countryside of Belgium’s Ardennes region, a huge compression is combined with cornering at high speed. “On the Nürburgring Nordschleife, the cars also bottom out at the lowest point of the Fuchsröhre passage.
But we don’t have the lateral forces there,” says Golz. After the downhill section with its 15 per cent gradient comes a left-hander at the lowest point followed by a sweeping, fast right-hand corner leading to a steep climb and the final left-hand kink through a gradient of 18 per cent. Visibility is very limited. For a short period of time, drivers see only sky and some treetops. “When you negotiate this passage for the first time, it’s a truly nail-biting experience, but you get used to it,” says Vanthoor.
“At around 240 km/h, not only the drivers but many components come under extreme stresses,” explains Golz. “Through the dip at Eau Rouge, the tyre gets extremely compressed, and at the same time lateral forces of up to 3.0g deform the tyre sidewalls. With the GT3 R, this means that around five tonnes is pushed to the outside of the corner. In the compression, the vehicle briefly bottoms out at up to 2.5g. The tyres alone can’t absorb these forces.