The Porsche 919 was billed as the most complex competition car the firm had ever built when it was launched at the Geneva Motor Show in early 2014. Built to the LMP1 technical regulations the car was designed with one purpose, to win Le Mans, something it achieved in 2015. Fitted with two hybrid systems the car was originally designed to run in the 8MJ category, but only ran at 6MJ in 2014.

The period between Porsche’s management taking the decision to return to the top level of the sports car world championship in 2011 and the Porsche 919 Hybrid appearing for the first time on the company’s in-house test track on 12 June 2013 was less than two years. During this period, a new office building and a workshop for the car was built at the Porsche Development Centre in Weissach. The team grew from zero to 230 staff, around 150 of them engineers. Machines, materials and components were procured, ranging from high-voltage equipment to a driving simulator.

The resulting car is powered by a 2-litre V4 engine, which has been extensively re-designed since it first hit the track in June, 2013. However, from the moment the car hit the track, a vibration issue with the V4 engine caused the interlinked suspension to break. A major redesign of the engine was commissioned early on, instigated by the Technical Director Alex Hitzinger. That engine, featuring a new crankshaft, was installed for the test in Portimao in which Mark Webber completed 600km.



The car features a MGU-K on the front axle in a similar arrangement to that of the Audi R18 and front system of the Toyota TS040. However the 919 differs in terms of its second hybrid system, instead of using a Toyota style rear MGU-K Porsche opted to use a innovative exhaust gas recovery method. Instead of opting for a Formula 1 style MGU-H layout with an electric motor linked to the turbo shaft acting as both an energy recovery system but also anti lag, Porsche’s layout has two turbines in the exhaust system, the first is part of a conventional turbo-charger layout in that it is linked to a compressor but the second turbine, which is sat alongside the first is only linked to an electric motor (GU-H), and not to a compressor or the other turbine. This layout allows the Porsche to recover energy at all times the engine is running, the only LMP1 design currently able to do this, all others are only able to recover energy under braking. Energy from both the MGU-K and the GU-H is stored in a battery provided exclusively to Porsche by A123.





The V4 engine powers the rear axle with over 500 bhp according to Porsche. When the driver recalls the stored energy from the battery, around 400 bhp drives the front axle additionally (at 8MJ). This way the Porsche 919 Hybrid temporarily turns into a four-wheel drive car with around 1,000 bhp system performance.

Technical analysis by Sam Collins

PRE LAUNCH TESTING: WEISSACH, MONZA, CASTELLET HTTT

Whilst few exact details have been released the images and information that has come out is fascinating in itself. Overall the aerodynamic package of the car seems largely conventional, but it is certain that the final bodywork has yet to be seen, but there are some clear pointers.



The car features a ‘legality bump’ in the roof (above) to allow it to meet the new minimum height regulations, something not seen on the rival Audi R18 or Adess/Lotus (also built to the 2014 chassis rules).



The cars power unit was at first thought to be a derivative of the never raced early 2014 spec Volkswagen F1 inline four engine, but recent information has revealed that this is not the case instead it is a turbocharged two litre four cylinder unit.

Videos such as the one above deliberately blur out the engine but there are clear signs that it is a V type engine. A V4 is very unusual format for a racing engine but thought to be a good one.



The engine is however known to use Formula 1 style exhaust gas recovery and an Audi style front mounted electric motor. Energy storage is a battery pack mounted in the passenger compartment with cells developed by A123 systems, who also supply a number of F1 teams. Not the single exhaust exit, suggesting that the car has a mono turbo layout.



Porsche has released a couple of interesting videos of the car (below), from these we can glean some further technical information, such as what appears to be Cosworth Electronics equipment in the cockpit.





LAUNCH: GENEVA

Porsche revealed the 919’s technical data at the Geneva Motorshow. The car will use Formula 1 style hybrid technology at Le Mans this year.



In 2014 the LMP1 category has adopted a Formula 1 style fuel flow limited formula which places the emphasis on energy efficiency rather than on outright performance. Unlike in Formula 1 there is great freedom in power unit configuration in LMP1, the internal combustion engines have no air restrictors or capacity limits which has seen Audi opt for a diesel fuelled V6, Toyota for a normally aspirated V8 while Porsche has opted a two litre turbo charged V4, an unusual configuration.



The front suspension layout is clear to see from the above image, which claims that rather than use the torsion bar suspension commonplace in LMP1 (and as used on the 9R6 RS Spyder) the 919 uses vertically mounted spring/damper units. This image was deliberate misinformation from Porsche, once the car hit the track it was revealed that the car featured a unique and complex suspension system which is still not fully understood, but is thought to split out heave and roll. Porsche deny that it is interconnected front to rear. The third spring/damper unit is clear to see and uses the high end Dynamic DSSV family of components, whilst the spring comes from the H&R firm. Note the bell crank at the right of the unit.



A central spring/damper unit is mounted at the front of the car, and a similar – but longitudinal layout is found at the rear (below) here we can also see part of the Turbo and GU-H layout.



This image reveals some of the major components at the rear of the car. This third spring/damper unit is clear to see mounted between the upper section of the transmission casing and a bracket on the rear face of the combustion engine (or possibly the bellhousing). Whilst much of what is present is covered by heat shields of various types half the turbocharger can be seen behind the Zircoflex gold covered plenum. What notably cannot be seen is the GU-H which is buried amongst the various shields and pipes.

To the left of the image the rear wing pillar can be seen mounting directly onto the upper part of the composite transmission casing, the upper wishbone pickup point is visible as are the shapes of the rear louvres. A high res version of this image is in the gallery at the top of the page.

The energy store is mounted in the cockpit area in the ‘passenger seat’. It is made up of battery cells from A123 systems. The very short V4 engine means that there is a very large carbon fibre bell housing ahead of the transmission (also carbon fibre).



Packaging is a key issue for the new 919, and dealing with the thermal demands of the power unit is a major area of focus.



The launch at Pal-expo gave the first proper look at the 919 in its launch spec bodywork. Many elements of the car appeared to be simplified, note the details around the front splitter (below)



The roof mounted intake has an interesting shape, it is not clear if the large support forms part of the roll over structure. The V-shaped section channels air to a pair of small intakes on the engine cover (below)



The bump in the roofline (above) is to allow the monocoque to meet the minimum chassis height rules introduced in 2014. This could suggest that the intake support is not structural. The purpose of the small ducts (below) is not clear, it is possible that they could be for transmission or ERS cooling. Note the bulge at the front of the main intake.



WEC PROLOGUE: CASTELLET HTTT

As expected a very heavily revised Porsche 919 appeared at the WEC Prologue in late March. There appears to have been more than one version of the cars bodywork fitted during a private session ahead of the Prologue, but some major changes are immediately apparent.



Firstly the nose of the car is totally new, the front opening is much smaller than the launch or early testing specification (below), and the nose is much flatter. The brake ducts have also been removed or included in the main nose duct. A look at the front splitter shows just how different it is.



These changes probably meant that the car required a new crash test, however as the car had not been homologated in launch specification it may not have been crash tested at all. This does not mean that the car was any less safe, just that the formalities may not have been conducted.



The roll hoop mounted engine intake has been totally redesigned, replaced by a seemingly smaller more curved duct (above). Interestingly the two intakes further back on the engine cover have been removed altogether.



What the ACO call “air extractors”, Mike Fuller calls “big honking holes” and we call mandatory wheel arch openings were also slightly modified on the Prologue spec 919. A small gurney has been fitted at the leading edge. New wing mirrors have been fitted also. Compare the original design (below) to the new design (above).



From the side the number of differences are very clear to see. Not least the three flow conditioning vanes in the area behind the front wheel pod.



The whole front pod area has been revised, compare the new (above) with the old (below), the front fender shape cuts inward toward the case and the headlamp shape is different. The upper rear portion of the wheel arch is totally different with a new opening just ahead of the wing mirror stalk (above the P1 sticker). Under that position the bodywork follows the shape of the wheel on the new bodywork whilst on the old it is far more angular. The leading edge of the rear wheel pod has also been reshaped and a new duct (probably for rear brake cooling) has been opened up on the flank.



A different bodywork configuration was trialled on the 919 in the pre Prologue test, it only appears in a few of the official images released by the German marque (below). The three flow conditioners behind the front wheel pod have been replaced with a single plate whilst the other elements remain the same.



The redesigned rear wheel pods have relocated the brake ducts from the leading edge to the flank of the car.



Compare the new design (above) to the old spec (below) the size of the brake duct looks to be much smaller.



Early in the cars development Porsche was outspoken in its criticism of the Gill Sensors Ultrasonic Fuel Flow meter with which the 919 ran in its first year. Gasoline cars must run with two sensors, diesel with three, but Porsche says that there is ‘no robust solution’ to the measuring process and doubts that there will be this season. ‘It hasn’t held us back because we did not make our development dependent on it, but there is still no robust solution in place,’ said Hitzinger. ‘The FIA is still very hopeful that the latest spec will work and will be reliable, but that is not proven yet. We optimise how they are mounted to give them the easiest possible life, but right now we don’t know if it is all going to be robust. We should know at the end of March.



RACE 01: SILVERSTONE

Wolfgang Hatz, Board Member for Research and Development of Porsche AG: “I am really proud. This was a proper comeback to the highest class of endurance racing. Preparation, operation, discipline in the garage and at the wheel of the two Porsche 919 Hybrids have been very good. The race itself was fascinating and this shows me that the new WEC rules work well – despite or even because of the great technical freedom. Three manufacturers, three innovative hybrid systems and exciting competition on the highest level. For me this is motorsport that contributes to road car development.”

Fritz Enzinger, Vice President LMP1: “Regarding our pace, I’m not too worried because the entire project is in its very early stages. The retirement of car no. 14 is annoying for all of us. With car no. 20 we had an entirely trouble free six hour race. Returning home with a trophy from the very first race is a great result for us and I think we should all sleep well tonight.”

Alexander Hitzinger, Technical Director LMP1: “Considering how complex this completely new technology is, it is very positive to have finished the race with one car. The no. 20 Porsche 919 Hybrid ran trouble free. We will have to have a long look into the reasons for the retirement of car no. 14.”

RACE 02: SPA

Alexander Hitzinger, Technical Director LMP1: “In car no. 14 we’ve had a false alarm which has switched off the hybrid system. Romain then had to do a time consuming reactivation procedure. We are very conservative when it comes to safety of our hybrid systems, so such a thing can happen and there is some homework to do. The Porsche no. 20 had problems with the rear dampers plus two failures of the front drive shaft. We knew this was a critical part and we are prepared to use stronger parts at the next test and in Le Mans. We have been fast in qualifying and in the race and brought both cars home – for us this was the most important target for the weekend.”

Studying the part numbers of the various components reveals that the car has an internal name of Porsche 9R9 which follows on from the name of the RS Spyder LMP2 design which had the internal name of 9R6.



Here we get a look at the right front corner of the 919, which the team keep built up in the garage complete with driveshaft, twin wheel tethers, wishbones, sensors and brake ducts. The composite components seen here have been made by the respected German supplier UBC.



Standing slightly to the rear of the 919 it is possible to get an idea of the airflow through the front of the car by looking through the louvres along the cars flank. In 2014 the LMP1 class cars are allowed to be fitted with what amount to fully adjustable front wings.



A good look at the air box used on the Porsche V4 engine, the upper portion is in plain carbon fibre, whilst the lower is coated in a gold thermal barrier. The air filter is housed in the centre of this component.

LE MANS TEST

From the Porsche post test press release.

Drivers Porsche 919 Hybrid #14

Romain Dumas: “Our car still tends to understeer and we will keep working on this for the race week. But both cars ran trouble-free, and that was our number one target.“



Both Porsche 919’s caught fire in the pit garage during the test, leading to hasty repairs.



All of the sections that burned were in the region of the turbocharger and generator unit as can be seen above – the GU-H is seen here clearly visible attached to its turbine. From the images above and the behaviour of the mechanics its clear that the turbocharger is the source of the heat but did not catch fire itself.



The legality of the Porsche 919 was questioned at the Le Mans Test day. During the official pre event photo session the updated 919 was seen for the first time by rival teams and it was noted that a significant portion of its engine cover and rear bodywork flexed with a gentle finger push.



The panels either side of a cutout around the rear crash structure deform visibly and will clearly lower when the car is at speed. This seems to be in breach of article 3.4 of the technical regulations which states that ‘Movable bodywork parts/elements are forbidden when the car is in motion.’

In 2013 the Toyota TS030 was fitted with a flexible engine cover which gave notable aerodynamic gains, but Toyota agreed not to use it in 2014.

Indeed the cut out itself around the structure is a contentious region as some have suggested that it breaches article 3.4.1c which states that the rear bodywork viewed from above should have ‘a continuous unbroken surface without cut-outs.’



Additionally the rear bodywork extends a few mm beyond the rear of the diffuser something that may contravene article 3.5.2 of the technical regulations which states that ‘No part of the diffuser must be more than 200 mm above the reference surface and its rear end must be plumb (Flush) with the perimeter of the bodywork (rear wing removed)’

It is not clear whether any protests will be lodged but the rear of the Porsche was of much interest to both Toyota and Audi

engineers.

UPDATE: LE MANS TEST DAY

During the test day itself it became clear that the Porsche’s were presented at the photo shoot in an incomplete state. When the cars actually hit the track the cutout over the rear crash structure was fitted with an additional panel which brought it fully in line with the regulations.



However even with the new panel fitted the rear bodywork visibly flexed at speed by a significant margin, something that will likely give a notable reduction in drag. It also still extends beyond the rear edge of the diffuser.



At high speeds the rear panels clearly deform. In the stationary position (above) the rear part of the engine cover is in line with the centre section panel, but at speed it drops substantially (below). Note the position of the breather pipe in both images relative to the body panel.



It is believed that both Toyota and Audi are seeking clarification over the legality of the Porsche design. It has been noted that a support or spar is visible on one side of the opening at the rear of the car and that it was missing in the shots showing flex. Even with the spar missing the flex was still evident.

UPDATE LE MANS 24 HOURS:

Alex Hitzinger has claimed that the rear bodywork on the Porsche 919 has been changed “We did not want to show everything at the test so there are some new things” he told Racecar Engineering ahead of free practice. It has been suggested that the changes were made at the specific request of the FIA though there is no confirmation of this. Additionally it had been speculated that the fires experienced by both cars on the test day were caused by the flexing engine cover getting too close to the turbocharger but this again is not the case according to Hitzinger “We changed the heat shield material around the turbo and we got it wrong, and it started to burn, once it started to burn then everything burns, but we have changed that.”



At the start of the race the two 919s had different specification front bodywork fitted.



The 20 car was fitted with a dive plane outboard whilst the 14 car had it removed Porsche claim that this is to do with balance of the car and driver preference.

