Porsche unveiled its brand new challenger for the 2017 season this weekend, laying claim to what the German manufacturer are calling the “most efficient combustion engine in the history of Porsche to date”. Still reeling from the excitement of the WEC Prologue, Curtis Moldrich has the lowdown on the upgrades and advancements made to the new spec Porsche 919 Hybrid.

Few races can match the history and pedigree of the 24 Hours of Le Mans. Having first taken place in 1923, the world’s most celebrated endurance race pits drivers and machines alike against the famous Circuit de la Sarthe – as well as against each other – for 24 grueling hours.

Fast forward to 2017, and Le Mans is still one of the fastest, most demanding sports events on the planet. But while the race remains the same, the cars have changed dramatically. Racing at near missile speeds as ever before – the cars regularly top 220mph down the Mulsanne straight – the notable difference these days is that the cars have effectively become development testbeds for the highly efficient hybrid technology that’ll one day power our road cars.

Porsche at Le Mans

While many famous marques – from Audi and Ford, to Ferrari and Bentley – have triumphed at Le Mans, no manufacturer can match the historic success of Porsche. Since the competition began, Porsche have won Le Mans a total of 18 times – including back-to-back wins in 2015 and 2016, meaning the Weissach-based team go into this season on a quest for a hat-trick of victories.

And it is with that backdrop that Porsche has unveiled its 2017 919 Hybrid – the most advanced car the German manufacturer has ever made.

Kicking out a huge 900PS (or 662 KW) of power, the new 919 Hybrid packs in a range of aerodynamic, chassis and powertrain upgrades on its 2016 car. And Porsche believes it is ready to fight Toyota in the war of attrition ahead.

“Each and every one of the nine endurance races presents a challenge. Reliability is the basic requirement; six hours of navigating around the many cars in the different categories, each driving at different speeds, makes each race unpredictable – and ultimately it is often only seconds that separate the winner from the rest of the field,” says Porsche’s Fritz Enzinger, Vice President LMP.

“Toyota is set to be a very strong contender in the top-tier LMP1 category for the 2017 season. We will face up to them with a meticulously enhanced Porsche 919 Hybrid, and a team of six first-class drivers.”

With four of those six drivers having previously won Le Mans – Nick Tandy, Earl Bamber, Andre Lotterer and Neel Jani – Enzinger’s confidence is justified.

Yet, though its historical rival Audi has now left endurance racing, Porsche has a resurgent Toyota filling its mirrors.

As such, the team’s engineers have made significant upgrades to last year’s Le Mans winning car: “For the 2017 season, 60 to 70 per cent of the vehicle is newly developed. The basic concept of the 919 Hybrid still offers scope to optimise the finer details and further boost efficiency,” says Team Principal Andreas Seidl. “The monocoque has remained unchanged since 2016, but the optimisation potential of all other components was analysed and, in most cases, adjustments made accordingly.”

Aerodynamics

On the outside, the new 2017 Porsche is completely different to before. That’s because new regulations introduced for safety have reduced the downforce levels of the prototype LMP1 cars – mainly to keep corner speeds down. “The aerodynamic losses we will incur due to the new regulations, we are expecting to see a three to four-second increase in lap times at Le Mans,” explains Seidl. “We will have to wait and see how well the various enhancements we have made will compensate for these losses.”

In attempt to claw back all-important downforce, Porsche engineers revisited every aerodynamic surface of the new 919 Hybrid, making improvements on some of the key elements from last year. As aerodynamic features become more intricate, F1 teams – and now LMP1 teams, too – have found they can be affected by even the smallest factors – including discarded tyre rubber.

Last year, Porsche engineers discovered the 919’s front aero features were disturbed by the accumulation of small bits of tyre – usually called marbles. “This rubber built up and upset the balance of the vehicle,” reveals Seidl. “We analysed this phenomenon and optimised the relevant bodywork components.”

Unlike F1, which features a more fluid, customisable approach to aerodynamic solutions, cost-saving measures mean LMP1 teams are limited to just two aerodynamic packages this year – one less than last year. As a result, you’ll see teams use a low-drag, low-downforce aero package for tracks with high top speeds – like Le Mans – but you’ll also see them use a higher-downforce package for twistier tracks on the calendar. Porsche can fine-tune the 919 Hybrid’s aero settings to better suit each circuit, but the new regulations mean it will have to compromise on setup more than last year. Thankfully for Porsche, it’s the same for Toyota, too.

Powertrain

The 919 Hybrid might look familiar on the outside at least, but the hybrid powertrain that powers the new racer is the most efficient engine Porsche has ever made. Again, just like in F1, the LMP1 rules are all about a combination of power and efficiency. And in the quest for even more bang for their buck, Porsche engineers have revised every upgraded area of the powertrain. On a basic level, it’s pretty similar: Just like last year, the new 919 Hybrid is powered by a petrol engine and electric motor; the engine used is a 2-litre V4 turbo, with a turbo and direct fuel injection that’s able to deliver 500hp to the rear wheels – and that’s not including the 919’s significant hybrid power.

The second half of the 919’s Hybrid power comes from a powerful electric motor that delivers over 400hp to the front wheels – and it’s amazing for two reasons: Firstly, it allows the car to have little to no turbo lag, thereby giving it incredible acceleration and traction. And, secondly, it also effectively makes the car four-wheel drive when using both power sources.

Reclaiming energy

Despite all this, the hybrid powertrain doesn’t just offer speed benefits; it’s also set up for efficiency. Like other LMP1 cars, the 919 Porsche is capable of energy recovery – the act of reclaiming energy that would usually be wasted, and putting it back into the powertrain. Porsche says around 60% of energy recovered by the 919 Hybrid comes from a KERS (Kinetic Energy Recovery System) on the front-axle brakes, and is intelligently looped straight to the engine’s powertrain, or the car’s lithium-ion battery, for later use. This ‘energy loop’ helps the 919 Hybrid save around a litre of fuel per lap around Le Mans, and also means it can run with smaller, lighter brakes which are better for both aerodynamics and weight saving.

The Porsche is also able to extract usually wasted energy from its engine’s exhaust system. Waste exhaust gases expelled by the engine typically turn a turbine at speeds of up to 120,000 rpm, which then recharge the 919’s Hybrid battery. And when the driver wants to use the extra power, all they have to do is put their finger on ‘Boost’ mode. However, there is a limit to the amount of reclaimed power that LMP1 cars can use. In Porsche’s LMP1 class, the cars can use 8MJ of recovered energy over a 13.629-kilometre (8.4 mile) lap of Le Mans, as long as it only consume a maximum of 4.31 litres while doing it.

Saving the tyres

Put all these highly-efficient systems together, and you have a 900PS, lightning-quick car that’s also able to extract the maximum performance out of every litre of fuel consumed. But even with this speed, Porsche’s car needs to be easy on its tyres – to reduce the number of tyre changes made per race. That might not seem massively important, but in a race that’s 24 hours long, it can be a crucial, strategic strength, as Seidl explains: “Working together with our partner Michelin, we have prepared intensively so that we are able to keep up the pace right through to the end of the race, even when we’re driving in double stints.”

All the races, whether six hours or 24 hours in duration, will be real sprints to the finish this year. During the night at Le Mans, when temperatures are cooler, even quadruple stints on one set of tyres are possible.

Crunch time

Indeed, at the Prologue, Toyota set the overall best lap time. Switzerland’s Neel Jani recorded the fastest lap for a Porsche 919 Hybrid on Saturday, lapping the 5.793-kilometre long track in 1:31.666 minutes. The reigning world champion will this year share the 919 Hybrid with Porsche newcomer André Lotterer, as well as Britain’s Nick Tandy, who returned to the LMP1 squad from inside the Porsche family. Together, the trio of the number 1 car covered a mighty 331 laps (1,906 kilometres) in two days.

And though the test provides a benchmark, the racing that will place across the season is another matter. Indeed, both Porsche and Toyota’s performance will only truly be revealed at the first round of the World Endurance Championship, which will kick off in earnest at Silverstone, on April 16th.