Porsche's Le Mans comeback: how it built winning 919 'from nothing'

Taking the fight to Audi and Toyota was a daunting task and would require something special. “For me, it was clear,” says Hitzinger. “I had to be very aggressive on the concept, because we had a lot of catching up to do compared to Audi who had been established for over a decade. We had to come with something radically new in order to make that change. That’s an approach that comes with its own risks.” Being tasked with returning Porsche to Le Mans and challenging for overall wins must rank up there with the most stressful jobs in racing, short of being Ferrari team principal.

Hitzinger was acutely aware of this.”The pressure was incredibly high, right? I mean, they were always coming back with that track record, we have to win, we’ll have to win fairly quickly. And that was a huge challenge. On one side, we started basically from scratch. And on the other side, you have this massive expectation.”

The sheer task of building a team to fight at the sharp end of sports cars should not be underestimated. It was not simply a case of hiring the engineers and other personnel, the right structures had to be established to ensure they all gelled together. The engineering and design processes also need to be schemed and implemented, to make the development and racing of a highly complex race car run as smoothly as possible. Luckily for Porsche, the end result – while far from perfect – was a potent machine.

Challenging Audi and Toyota 

The 2012 onwards LMP1 era was the pinnacle of technical advancement in sports car racing. Though the current Hypercars look shiny and fast, they are technologically restrained race cars by comparison. Governed by rules that would eventually become the sometimes confusing and always controversial Equivalence of Technology regulations, the class sought to create a level playing field for different powertrain and fuel choices, without artificially balancing the overall performance of the cars. The idea being that whether petrol or diesel was used, and regardless of hybrid system choice, there would be no inherent disadvantage to picking one route over another.

The result was frankly, wonderful. Audi continued to refine its diesel-kinetic flywheel powertrains, Toyota arrived in 2012 with an NA petrol V8 and supercapacitor-based hybrid, then Porsche in 2014 appeared with its left-field gasoline V4 harnessing both kinetic and exhaust gas energy recovery.

In some respects, Porsche’s powertrain approach was the most unusual of the three manufacturers. At the heart of the 919 was a 2.0 litre direct injection V4 petrol engine, boosted with a single turbocharger. The output was augmented by two energy recovery systems, a front mounted motor and an exhaust driven generator. Porsche initially opted to run in the 6MJ energy recovery class(equating to filling an approximately 1.7kWh battery over each lap of Le Mans). Audi was in the 4MJ class while Toyota matched Porsche at 6MJ.

Speaking at the 2014 24 hour race, Hitzinger explained why the company opted for such a configuration. “The turbocharged engine is very efficient in combination with direct injection, we followed the downsizing concept because it is compact and light. We went for a vee configuration because it is compact and stiff, if we went for an inline four, we could not achieve what we wanted. The choice was then between a four or six-cylinder, and it was a matter of picking the best compromise. We wanted a certain dynamic efficiency as well as a particular ratio between bore diameter and combustion chamber volume, which in turn led us towards a bigger bore diameter. Hence the choice of a vee four.”

Recalling the early days of the project, Hitzinger suggests that though the V4 was certainly unique, it was not in his opinion the technological highlight. “The biggest innovation was actually the hybrid system and the battery concept, we were able to go early on to the very large hybrid system where Audi has a very small one, that was a performance benefit.”

Porsche’s approach to thermal energy recovery was an interesting one. Whereas in Formula 1, the MGU-H is directly attached to the primary turbocharger, this was not the case with Porsche’s system. In the 919, the electric motor and the turbocharger were mounted separately. Instead of having a wastegate, as is usually found of a turbocharged car, the exhaust gases that were surplus to requirements – once the required boost level is met – fed through a secondary turbine that turned an MGU. Power was fed either into the battery storage or, potentially, directly to the front mounted MGU. Porsche’s reasons for choosing this system were multiple, but notably centred around the inherent reliability of the setup, if the MGU-H were to fail, it would not disable the car.

Direction change

It was not all smooth sailing during the 919’s development and one particular issue almost derailed the project. This related to the fact that V4 engines are prone to vibration, something that Porsche experienced with early iterations of the 919’s. The vibrations were known about, but it was only once the car hit the track that their severity was truly appreciated. “When we were running the car for the first time in Weissach, its first roll out, I saw how it behaved and on that day, I made the decision. ‘Okay, we’re going to change’,”recalls Hitzinger. “We immediately kicked off [development] of a new crankshaft and new camshaft so that we could change the firing order. If I hadn’t made that decision, I am certain the programme would not have been as successful.

Fortunately, the engine department was not precious about its design and understood the need to rectify problems. “They accepted the decision and then pushed really, really hard. They made it happen very quickly, and it was really was very good.”

Maturing to domination

“Initially, as is very normal with a new car, you start off quite slow but once we sorted the vibration issues a rate of progress was immense,” remarks Hitzinger. The process of ironing out all the teething issues can be hard on a team with the potential for frustration to fester. But as the 919 got into its stride pre-season the mood within the team lifted. “Once progress sets in it is immensely motivating,” says Hitzinger. “We rounded that corner at the end of 2013. Really just in time for the season and that’s what really turned the team around.”

Through its debut season, it was clear that the 919 had the pace to fight for overall wins but more often than not it was hobbled by reliability issues. At Le Mans, both cars entered fell by the wayside, the only finishing car coming in over 30 laps down on the winner. It was always going to be a tall order to win on its debut, but the 919 showed its intent with a win at the last round of the WEC season in Sao Paulo. As an interesting aside, both Porsche and Toyota were guilty of some trickery with their Le Mans aero packages in ’14.

For Porsche, eyebrows were raised at the somewhat flexible rear engine cover the 919 sported. Running in a continuous section across the trailing edge of the body, the bodywork (with a small Gurney flap) was able to flatten out at high speed. Come the Le Mans race, the bodywork appeared with supports to stop this happening – words had clearly been had behind closed doors.

However, while all eyes were on Porsche, no one seemed to notice what Toyota was up to. Watching the TS050 at speed, it became apparent that the entire rear wing section was able to tilt backwards, reducing drag. We’re not talking just the top element, like a DRS system, the whole rear section of bodywork, endplates and all was able to twist, while still passing all of the required tests. Toyota remains tight lipped on the matter, but for 2015 the FIA tweaked its rules to prevent such shenanigans.

Porsche’s Le Man comeback 

Not only was the win in Sao Paulo reassurance for the Porsche team that it was on the right track, but it had also won with a car it knew was compromised in many areas. An all-new design was already testing ready for 2015. Reflecting on that win, Hitzinger notes wryly, “It was quite amazing, because we knew what we were going to make for the next season! Before the first race [of 2014] we were planning to redesign the whole car.”

Armed with experience of the opening rounds of the season, the 2015-spec 919 would be leaner and meaner than the first. It is easy to assume that Porsche threw unlimited resources at the project, but Hitzinger is adamant this was not the case, and it lagged Audi’s spending considerably. This meant that instigating dual development programs on the ‘14 and ‘15 cars was far from easy. “Running that first year, and having all that pressure while in parallel, we designed a basically completely new car for 2015. That was a huge amount of work,” he recalls.

The team pursued an even more aggressive concept for the new season, moving up to the 8MJ energy class and optimizing every area of the car while also bringing more processes in-house. A fresh monocoque was designed, which Hitzinger says (combined with savings across the rest of the car) shed a scarcely believable 40kg of weight. The team also got its aero department in Weissach up to full speed, having worked with a technical partner on the debut car. “To have full control over our own aerodynamic development, that was one of the most important performance factors. Bring that all in-house, building the aero team from scratch, that all paid off,” asserts Hitzinger.

The result was a devastatingly effective car, which Toyota and Audi had no answer to. Despite some wobbles in the opening races of the season, come Le Mans Porsche was unstoppable; not only winning the race but securing a 1-2, clear of the trailing Audi by a lap. Le Mans set the scene for the rest of the WEC season, Porsche triumphing in the remaining five races.

Porsche vs Toyota 

Despite Toyota in particular upping its game for 2016, Porsche remained the team to beat. The updates were not as significant as the previous year, but highlights included an all-new, composite transmission casing as well as revisions to the battery system including a new cell chemistry. Everything appeared to be well with this new specification until the second round of the WEC at Spa, where one car suffered a problem with the battery energy store. “We did analysis after the race and found out that we had a problem with the latest generation of cells,” said Seidl just before Le Mans. As a result, Porsche opted to revert to its 2015-specification cells, which it would retain until the end of 2016.

Porsche was as rigorous as ever with its pre-Le Mans testing, with Seidl outlining that the ideal testing schedule consisted of “a mixture of endurance and performance tests, with the basic goal being to complete four 30-hour tests with a new car specification.” Porsche’s final 30-hour test was completed just after the Spa round in May, and Seidl said the multiple tests invariably threw up problems that had not been experienced before. “The basic idea is that at the third test, you have the Le Mans specification ready, then for the fourth test, you keep that configuration but with the latest production batch of parts which will be used at Le Mans.”

Interestingly, he also noted that for the first time since the introduction of the 919, the team was able to run the full duration of its final test without any issues stopping the car. As the race was to show, however, no matter how many such tests are run, unexpected problems will always crop up. In the case of the No1 Porsche, a problem with the coolant system saw the car spend an extended period in the pits. These problems, coupled with the ferocious pace of Toyota nearly led to an upset, but in the end Porsche triumphed once again.

Rolling into what would be the final year of the project, Porsche further revamped the 919 for 2017. The 2.0 litre V4 engine remained externally similar to the 2016 unit, but its internals were heavily revised. For the first time, Porsche used a pre-chamber ignition system, allowing it to run even leaner mixtures than in 2016, thus increasing power output for the same fuel flow limit. Seidl (by now team principal and technical director following Hitzinger’s departure), noted at the time: “A huge contribution to the performance increase has come from the combustion engine, with more power and greater efficiency.”

One area that Porsche worked extensively on with its ’17 car was improving the balance and pitch sensitivity. This was partly to address shortcomings with the 2016 car and to accommodate new rules for 2017 that limited teams to four sets of tyres for six-hour races, meaning double stinting became a necessity. “We have done a lot to make sure the tyre life is a good as possible,” said Seidl. “There is a lot you can do with your systems – the chassis kinematics, traction control, the hybrid deployment – to make sure you can extract the maximum performance over the length of a stint.”

Of course, the car is not the only factor to consider when trying to win the Le Mans 24 Hours, with every element of a team having to run perfectly – even when, as Porsche and Toyota would experience, unforeseen circumstances need to be adapted to quickly. As such, Porsche focused on improving its operational strategies, and this preparedness paid off. Every detail was assessed, from the organisation of the garage to physical parts on the car. For example, Porsche introduced a Formula 1 – style wheel nut retention system, shaving a few tenths off its pit stop times.

As Seidl pointed out: “We are now into the fourth year of this project, and we have achieved the next level in terms of preparation before coming here. The pitstops have moved on another step too, so it is a case of executing what we have learnt in the past six months.” And so it would, beating Toyota in the garage and going on to secure its hat-trick of Le Mans wins. Shortly after Le Mans, it was announced that Porsche would follow its Volkswagen Group stablemate Audi (which cancelled its program in 2017) out of LMP1. It was shifting its sights to thebrave (and much cheaper) world of Formula E and with little left to prove at Le Mans, the team’s exit left Toyota the sole remaining works entry. So started the Japanese team’s current, unbroken winning streak.

However, the 919 did not slip quietly into retirement and through 2018 the 919 ‘Evo’, unrestrained by regulation, set about beating a host of lap records around Europe including a truly epic performance around the Nordschleife. Great as it is to see Porsche back at Le Mans with the 963 LMDH, one can’t help but pine for the glory days of LMP1. It was truly the technological peak of sports car racing, with the boundaries of both technology and lap times there to be broken.