Porsche Built A 911 With Portal Axles To Go Where Unimogs Can't Reach
No car has ever driven at higher altitude than this 992-generation Porsche 911 Carrera 4S with portal axles. On Saturday the Porsche crew, led by racing driver Romain Dumas, reached the highest peak of the west ridge of the Ojos del Salado volcano in Chile, after doing an exploratory run up to 19,000 feet in 2022. That’s the tallest active volcano in the world, for anyone keeping track, stacking up at just over 22,000 feet above sea level. The new 911 C4S still has its stock 3-liter turbo flat-six engine and 7-speed manual transmission.
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Image: Porsche
Racing driver Romain Dumas has conquered basically every discipline of motorsport where he’s driven. He’s got wins in the 24 Hours of Le Mans, Pikes Peak Hillclimb, 12 Hours of Sebring, 24 Hours of Nurburgring. He’s won an FIA rally championship. He’s placed at the Dakar rally. He owns the outright lap record at the Nurburgring. The guy’s done it all, so now I guess he’s set his sights on breaking more records.
Image: Porsche
The Carrera 4S’ 443 horsepower at sea level is more like 150 at this kind of altitude, and with the gear reduction effect of the portal axles, this 911 probably wasn’t moving all that quickly. It’s not an exact number, because the turbochargers on the engine help reduce the effect of altitude horsepower loss, and it’s near impossible to get an exact rating without hauling a dynamometer to the top of that same mountain. In any case, it was a lot less than the car would have 205 miles away in the coastal town of Caldera.
According to Porsche, these cars were remarkably stock, considering their purpose and the final look.
The two cars were equipped with carbon fiber seats, and five-point harnesses. Next, portal axles were added to increase ground clearance (now 13.7 inches / 350 mm). The portal axles also had the effect of reducing the gear ratios, allowing for precise, gentle throttle inputs at low speed. In addition, the cars were equipped with special lightweight but extremely tough Aramid fiber underbody protection to allow sliding over rocks.
The lead car received a very special additional piece of technology – steer by wire – developed and provided by Schaeffler Group. The system called Space Drive was capable of meeting the unique and extreme demands of the volcano and the terrain, offering precision and detailed feedback to allow Romain Dumas to place the car precisely where he needed it – often while ascending precarious and near-vertical slopes.
Image: Porsche
22,000 feet is a massive height. For context, the highest paved road in the world is the Karkoram highway between China and Pakistan, at roughly 16,000 feet. Pikes Peak in Colorado is just 14,115 feet by comparison. I’ve had altitude sickness at the top of Pikes Peak, so I can’t fathom climbing another 8,000 feet above that. The team took two weeks to reach the summit, as they would only climb a little each day to slowly acclimate to the increased altitude. Two doctors went along for the ride to keep track of the team’s health. That’s probably for the best.
