Le Mans is known around the world for its long straights and famous passages. Corners like Tertre Rouge and iconic features like the Dunlop Bridge get adrenalin pumping in the hearts of endurance fans. However, there is another section that features even higher on the spectators’ list of favourites: the Porsche Curves. Originally, only the long right-hander (Turn 23) after the Arnage curve was given the name Porsche. Now, this title also encompasses Virage du Pont, Esses du Karting and Virage Corvette. The flowing combination of two right-hand and three left-hand turns throws major challenges at teams and drivers – when it comes to downforce and grip, the racing cars reach their absolute limit.
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“If you want to be fast over an entire lap at Le Mans, you have set a very fast pace on the long Mulsanne straight,” emphasises the head of operations Alexander Stehlig. “We aim to reach over 300 km/h on the straights. This makes overtaking easier, and that’s important at Le Mans. To do this, the Porsche 911 RSR – like all other cars – is trimmed for very low drag. This means little downforce. It’s a dilemma, because we actually need maximum downforce, particularly in the fast Porsche Curves,” states the engineer. Why is the setup not adjusted to the requirements of the fast corners? The potential lap-time gain would never be able to offset the disadvantages of a slower pace on the long straights.
“Based on the low downforce setup, we still have to ensure that the car is well balanced for cornering,” says Stehlig. “And that’s tricky because, through the Porsche Curves, drivers play with the throttle pedal. Sometimes they drive at half-throttle, sometimes they go full-throttle. That results in load changes and so-called pitching – where the front of the car sinks as soon as there’s less thrust. This shifts the aerodynamic balance forward. The car then turns in quickly, but this can easily lead to oversteer, and no one really needs that there. So we make sure that the aerodynamic baseline is as stable as possible and therefore the car remains predictable. That’s the key to success on this part of the track.”
In the five curves, the speed fluctuates within the narrow range of 189 to 228 km/h. In each curve, the centrifugal forces reach 2.29 to 2.42 g. Other data also underscores just how fast the Porsche Curves are: The good one-kilometre-long stretch makes up 7.5 per cent of the entire lap. It takes the 911 RSR just 17.6 seconds to get through the five-curve combination at speed – which translates to around four per cent of the entire lap time, or an average of around 3:50 minutes for the GTE-Pro racers. In keeping with the name of this spectacular passage, speed is the trump card. Under normal conditions, the best place for fans to watch the action is from the nearby ferris wheel. “From that vantage point, everyone can see that it’s not simply about gentle sweeps. The Porsche Curves are tight, you experience brutal g-forces. From the cockpit, the barriers, which are often very close to the track, make the legendary passage look even faster. It’s a dream for real racers,” enthuses Bergmeister.
As soon as two vehicles meet in the fast passage, time will be lost. “When you encounter a slower car, it’s hard to get past. If it’s a prototype that overtakes you, downforce is lost for a moment, you get annoying understeer and at least two-tenths of a second go down the drain,” says Bruni. Since the vehicle has to be perfectly balanced through the Porsche Curves, understeer costs speed. Completely reliable turn-in is essential for the swift changes in direction at over 200 km/h – for safety reasons, as well. “The barriers and run-off zones were changed again and again in recent years, but the basic characteristics have remained almost the same. The Porsche Curves represent an old-school passage,” emphasises Jörg Bergmeister. “Which means, even with sealed run-off zones and the SAFER barriers, sliding off the track there will very probably result in a write-off. Therefore, a controlled attack is the key to the Porsche Curves.”
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