Porsche will tackle the 2017 racing season with an all-out newly developed GT racer. The new 911 RSR makes full use of the rather loose GTE regulations and has its flat-six engine positioned in front of the rear axle. The four-litre unit features direct fuel injection as well as a rigid valve drive.
“While retaining the typical 911 design, this is the biggest evolution by now in the history of our top GT model,” says Head of Porsche Motorsport Dr Frank-Steffen Walliser. According to information from its launch the new 911 RSR is a completely new development: the suspension, body structure, aerodynamic concept, engine and transmission have all been designed from scratch.
The engine concept has enabled the designers to install a particularly large rear diffuser. Combined with a top-mounted rear wing the level of downforce and the aerodynamic efficiency were significantly improved over the 991 GTE.
“For the 911 RSR, we deliberately focussed on a particularly modern and light normally-aspirated engine, as this gave our engineers immense latitude in developing the vehicle,” explains Dr Walliser. “Apart from that, in principle, the LM-GTE regulations stipulate the absolute equality of various drive concepts, as the torque characteristics of turbo and normally aspirated engines are aligned.” Depending on the size of the restrictor, the new normally-aspirated unit puts out around 375 kW (510 hp).
Paddles on the steering wheel actuate the sequential six-speed gearbox which features a magnesium housing, which delivers power to the 31-centimentre-wide rear wheels.
For the first time, a Porsche GT race car features state-of-the-art assistance systems: the new 911 RSR is equipped with a radar-supported collision warning system, the so-called “Collision Avoid System”. Even in the dark, the faster LMP prototypes are detected early enough and misunderstandings can be avoided.
A new safety cage concept and a new, rigidly-mounted racing seat enhance driver safety. With the seat fixed to the chassis, the pedal box is adjustable to suit different drivers.
The new 911 RSR’s serviceability has also been significantly improved according to Porsche: Entire elements of the carbon-fibre body can be exchanged completely in a very short time thanks to clever quick-release fasteners. Moreover, changes to the suspension setup can be performed much more quickly and easily.
Le Mans 2017
The new Porsche made its race debut in the USA, but on arrival in the WEC it attracted a lot of interest right away, however not everything has gone to plan. While the car was generally competitive in the opening races of the 2017 WEC season it also did not really challenge the Ferraris and Fords in terms of outright pace, and the story was the same in the IMSA series in the USA. While some suspected ‘sandbagging’ the reasons may be somewhat more serious.
When the cars arrived at Le Mans there was a distinctive change at the rear end, with both cars fitted with an entirely new exhaust system. Such a major change on a homologated car is extremely unusual and would have likely required the agreement of rival manufacturers.
What is curious is that such changes are usually made for reasons of reliability rather than performance, and the Porsche’s managed to finish the Daytona 24 Hours, though at the opening race of the WEC there was an engine compartment fire. Compare the original specification exhaust and diffuser arrangement (below) with that of the new specification (both pictures above).
Note that the new exhaust is entirely different in layout to the original specification with the tailpipes relocated to a central position. Also of note is the additional heat shielding on the upper surface of the diffuser.
The exhaust was not the only change made to the Porsche at Le Mans, at the front of the car only a single dive plane was used.
Compare the WEC Silverstone setup (below) with the Le Mans variant (above).
Yet another variance between the WEC and Le Mans specific aerodynamic package can be seen on the rear wing of the Porsche.
A different rear wing mounting bracket was installed at Le Mans – note the number of holes in the WEC version (above) and the Le Mans spec (below)
Here we get a good look at the four litre flat six engine used in the 2017 Porsche GTE. It features direct fuel injection, a dry sump lubrication system and four valves per cylinder. The bore is 102mm and the stroke 81.5mm. Note that the oil tank sits at the rear face of the engine block.
With the transmission mounted to the engine. The gearbox features six speeds and has electronic sequential shifting (via steering wheel mounted paddles) the casing is magnesium. It has a twin shaft longitudinal layout.
A look at the outboard front suspension and upright. The four way adjustable damper with dual coil over springs and just be seen mounted to the inner face of the upright. Although the brake disc and caliper are removed the brake cooling layout is clear to see.
A nice overview of the 2017 Porsche GTE car as it is prepared for the Le Mans 24 Hours.
