Abbreviations RSR were born in 1973, when Porsche decided to participate for the first time officially with 911 in the 24 Hours of Le Mans and created a special unit for competition that was not homologated for the road. The actual Porsche 911 RSR is most extreme evolution of this concept, a development that has been determined by the regulations LM GTE. Taking advantage of the regulations, the engineers of the German company have relocated the engine, placing it in front of the rear axle, thanks to which more space is achieved for the aerodynamic elements and a better distribution of weights.
Ten of them will compete in the 24 Hours of Le Mans 2018, four in the LMGTE Pro category and six in LMGTE Am. The production of these exclusive competition units is carried out in the center of Porsche Motorsport, in Weissach.
The construction of the 911 RSR starts with the bare aluminum body of a Porsche 911 street car, without the exterior panels. This part leaves the Stuttgart production line and receives a deep restructuring work when it comes to Porsche Motorsport, it affects several sections. First, it is reinforced with new welds, supports for various elements and the steel safety cage, homologated by the FIA.
“We didn't have to add a lot of things because the body is very solid, even without the roll cage. The front and rear areas are very safe and allow a lot of deformation. The most difficult thing is to protect the rider from side impacts, and for this reason we focus the driving position as much as possible ", he assured Marco Ujhasi, responsible for the Porsche GT Project.
The most complicated work is done at the rear, so that the engine, transmission and rear suspension mounts can be relocated. The 911 RSR starts with the GT3 engine, but positioned in front of the rear axle and in a longitudinal position.. Despite this, "the excellent modular design of the 911 means that we have kept about 85% of the original structure," according to Ujhasi.
The sequential gearbox is anchored behind the engine via a new magnesium casing. All this means that the rear axle is placed in a position 6,6 cm further back than in a Porsche 911 street, which also increases the wheelbase and configures a body 5,8 cm longer (4,55 meters of length without ailerons and diffuser).
The new LMGTE regulation allows a lot of aerodynamic development in the cars and Porsche Motorsport has worked hard on the 911 RSR to achieve maximum efficiency in this area. All exterior parts of the body are made of carbon fiber and its design has also taken into account the reduction of repair times in the race, with quick disassembly systems.
The main reason that led the engineers to advance the engine was to make room for a huge rear diffuser, which greatly increases downforce and works in conjunction with the rear wing and front apron. This new set has made it possible, in addition to gaining efficiency, making driving easier and extending the life of the rear tires.
The aerodynamics were fine-tuned through hundreds of hours of computer work with CFD fluid dynamics programs, before using Weissach's 1: 1 wind tunnel, capable of simulating curves. Another highlight of this development was providing the necessary cooling to the 4.0-liter six-cylinder boxer engine and the transmission. For this reason, new, larger air intakes were designed in the rear wings, behind the doors.
The 510 PS 911-liter naturally aspirated boxer engine used in the 40 RSR is up to XNUMX kg lighter than an equivalent turbocharged engine., which results in better weight distribution and a lower center of gravity. What's more, the naturally aspirated engine offers more possibilities for engineers to evolve, its cooling is simpler and reliability is ensured by having fewer systems that can generate problems in the race.
Increased power and performance have grown the Porsche 911 over the years. The wheelbase is a clear indication: from the initial 2.211 mm of the first Porsche 911S that participated in Le Mans in 1966, to the 2.516 mm of the current Porsche 911 RSR, there is a 30,5 cm difference. In fact, the 911 RSR has 6,6 cm more wheelbase than a Porsche 911 Carrera on the street.
Monta very wide tires to ensure traction, braking and reducing understeer. At the rear they are 310mm wide (the only Porsche 911 with wider tires is a street GT2 RS), and at the front 300mm. By regulation the wheels are 18 inches in diameter.
As drivers spend hours inside the car in the most extreme conditions, they are offered comforts such as a air conditioner (without it it could exceed 60 degrees, increasing dehydration), power outside rear view mirrors with memory function to adjust to each driver as he enters the car and a little known system is the heated windscreen to avoid mist when it rains.
In addition, the 911 RSRs participating in the 24 Hours of Le Mans are equipped with an advanced anti-collision warning system with radar. It informs the driver of the approach of other cars, their direction and speed, and warns before a possible collision, something of essential help with the large speed differences that exist at Le Mans between the LMGTE and the prototypes. With this, safety is reinforced under difficult conditions at night, rain or heavy traffic situations.