It takes a brave driver to handle this corner flat out.
While we're still waiting for the next-generation Porsche 911 GT3 RS to arrive, its race car sibling, the 911 GT3 R will face one of its toughest challenges this weekend. During the 24 Hours of Spa-Francorchamps on October 24 and 25, drivers will encounter - lap after lap - the famous Eau Rouge, regarded as the world's most dangerous corner. Named after a small creek with red-tinged water, the challenging section starts with a steep downhill section with a 15-percent gradient before a tight left-hander at the lowest point, followed by a high-speed sweeping right corner.
This leads to a steep climb before the final left-hand kink through an 18-percent gradient. "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.
What also makes the Eau Rouge so challenging is its low visibility - for a short time, the driver can only see sky and some trees. "When you negotiate this passage for the first time, it's a truly nail-biting experience, but you get used to it," says Porsche factory driver Laurens Vanthoor. Some drivers are brave enough to tackle Eau Rouge flatout during qualifying sessions, but this isn't a wise tactic during an endurance race as the tires need to be preserved for as long as possible.
In 24 hours, the car will cover a distance of over 1,553 miles. Weighing more than 2,645 pounds plus driver and fuel, the car's weight is also much higher than in qualifying. At around 149 mph, the GT3 R is put through a tremendous amount of stress. The tires get compressed and lateral forces of up to 3.0 g deform the tire sidewalls.
"With the GT3 R, this means that around five tonnes is pushed to the outside of the corner," said Golz. "In the compression, the vehicle briefly bottoms out at up to 2.5g. The tires alone can't absorb these forces. The rims distort and even the chassis seems to groan under such loads. Thankfully, our Porsche 911 GT3 R has a stiffer design compared to some other GT3 vehicles. We've seen the chassis of cars breaking when they hit the dip down at Eau Rouge."
Setting up the car correctly to tackle Eau Rouge also isn't easy. If the suspension is too soft, the car will bottom out, but a hard setup might result in having one wheel in the air without surface contact.
Fast corners require a low ride height, while sections with rapid direction changes require a hard suspension, which isn't an ideal setup for Eau Rouge. "You're always looking for the best possible compromise," the Porsche engineer explained. "I can live with the car bottoming out slightly in Eau Rouge because I want the car low through other passages. One shouldn't forget, the lap time doesn't just depend on Eau Rouge - it is achieved over the entire seven kilometers. The Eau Rouge is always a huge challenge. It's a brave driver who keeps the throttle pedal down through here."
Based on the 911 GT3 RS production car, the GT3 R is powered by a 4.0-liter flat-six engine tuned to produce 550 hp, paired with a sequential six-speed gearbox. It also features improved aerodynamics over its predecessor and a massive rear wing that provides significantly more downforce than the road car.
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