L&T Motorsport

Porsche 919 Hybrid 2.0L Turbo V4 vs Mercedes W06 F1

With LMP1 and F1 being the pinnacle of their respective disciplines, with Le Mans Prototype 1 being seen as the pinnacle of sports car racing and Formula One as the top single seater class, the question has always been about which is the more advanced, more challenging discipline of racing. To put it simply, which ‘top class’ has the advantage in car racing and could be seen as the more impressive of the two. In 2016, Top Gear’s Ollie Marriage sat down to compare the technical regulations of the 2015 Champion-winning cars in each class: the Porsche LMP1 919 Hybrid 2.0L Turbo V4 that won Porsche’s first Driver’s Championship since joining the World Endurance Championship with Brendon Hartley, Timo Bernhard and Mark Webber, and the Mercedes W06 F1 challenger that took Lewis Hamilton to claim his third Formula One World Championship.  

Mark Webber made comment after the 2015 6 Hours of Shanghai, stating that the LMP1 “fastest lap in qualifying was only half a second slower than Lewis’ fastest race lap.” It has always been assumed that there is a big pace deficit between the Formula One cars and the LMP1s, with the advantage falling to the single seaters. By getting access to competitive telemetry from Mercedes and Porsche around Spa-Francorchamps, we can start to draw on comparisons and see if there is any truth to that assumption.  

The first aspect of analysis and comparison between these two great machines is at a basic level: that Formula One is twice as technical as LMP1, the teams have a lot more rules and regulations to follow and adapt to and have a lot more advanced technology in their cockpits. This is true in part. Technologically, LMP1 and Formula One are on a similar level with technological developments and advanced technology on the cars. The real difference comes from the freedom teams have in using and adapting these regulations. The LMP1 teams are given energy allowance and allowed to do what they want within that allowance. However, for Formula One, not only are the allowances set, the FIA also dictate how the allowances should be adapted. This gives more vary in technology in the LMP1 field and sees very little difference in the Formula One cars, leading to why recently the grid has been so engine-dependant.  

A side note at this point that the original analysis was completed in 2016, before the 2017 aerodynamic rules came into action. But even so, these rules did not see a huge variety of ideas down the Formula One grid.  

The regulations of the 2015 Formula One World championship saw that the cars were limited to 100kg of fuel per race, something that has been a big discussion point in the sport since its introduction. The power units for the 2015 season are constructed of six parts: the 1.6 litre V6 engine, the turbocharger, kinetic energy recovery system (MGU-K), heat energy recovery system (MGU-H), energy store and the control electronics. The energy store is the only aspect of the power unit that comes with some variety. Teams have the choice to choose either a battery, supercapacitor or flywheel as their energy store system. 

Power figures are not discussed in the Formula One technical regulations, but it is widely accepted that V6 turbos deliver about 600-650bhp. The electrical power of the hybrid engine is restricted to 161bhp. With all this technology and power units on board, the car and driver has to have a minimum combined weight of 701kg.  

In LMP1, the only restriction that teams have on their cars is the rate of fuel flow. Depending on how much electrical energy teams want or can produce per lap depends on rate of fuel flow they are allowed. The more electric power you have available in a lap the less fuel you are allowed in a lap.  

Unlike in Formula One, where everyone runs the same regulation of power unit (in 2015, every team’s energy store was powered by a battery), each of the LMP1 teams took on a different approach to their engine sizes, thus altering how much fuel flow they have in the cars and mixing up the competition. In 2015, Nissan arrived to Le Mans running a front-wheel drive with a flywheel energy system and two megajoules of electrical power per lap. Audi Sport took on four megajoules per lap with the 4.0 litre V6 diesel engine. Toyota ran six megajoules per lap with a naturally aspirated V8/supercapacitor TS040.

When talking about Porsche, a closer comparison between the Porsche 919 Hybrid and the W06 F1 can be conducted. For the 2015 season, Porsche ran a power unit that was very like those found in Formula One. Their small-capacity petrol engine, a 2.0 litre V4 turbo, was linked to two hybrid systems and was designed in a very similar way to the Mercedes power unit for Formula One.  

Power is, like in Formula One, not openly discussed, but the V4 turbo in the Porsche is accepted to deliver over 500bhp. The combination of two hybrid systems (kinetic from brakes, heat from exhaust gases) is where Porsche’s advantage shows. Porsche says that their system, in 2015, let out 400bhp but the rival teams claimed that it could be much higher than that, going as far to say 750bhp. The 919 weighted 950kg, with the driver on board, in 2015.

With these similar weight-to-power ratios, the comparison between the two 2015 champions can really take a close look at which could potentially be classed as better. The W06 comes out behind in the brake horse power per tonne calculation. 1140bhp/tonne is calculated for the W06, whilst the 919 has about a 200bhp advantage, getting a 1310bhp/tonne calculation.

This, however, is a very basis comparison. The two cars are built to race very different disciplines of racing. The 919 needs to keep up a consistently fast pace for up to 24-hours whereas the W06 needed only to complete a 2-hour race. 

Take off the body work of both cars and you could believe you were looking at two cars that raced in the same category. It is the closed cockpit and the faired-in wheels that gives the 919 much lower drag than the W06. Without the bodywork, both cars would produce similar downforce levels, believed to be about 700kg at 80mph

The question you may be asking is how, with the power advantage, does the LMP1 car not race faster than the F1 in a straight line? It is because electrical power is used differently by both formulae of cars. Because the Formula One cars are restricted to 4MJ of electricity over 161bhp, the supply depletes slower than the 919-Hybrid which has 8MJ over 700bhp. The straight-line speed advantage, if the two cars were to have a drag race, would show off the start line. The 919 accelerates much faster than the W06 as this is where Porsche uses their electrical power supply.

The weight of the cars also gives the advantage to the W06. Weighing 250kg more than the W06, the Porsche loses braking and cornering speed to the WO6. If you look at the overall comparative qualifying lap times around Spa-Francorchamps, the Mercedes F1 car had an overall lap time that was 7.57 seconds faster than the Porsche 919 LMP1. The gap was smaller in the race, but the LMP1 cars would still have a big pace deficit to the Formula One cars. These results are also produced when comparing lap times of both classes at Silverstone, Shanghai, Bahrain and Austin.

Webber is one of the only drivers to have raced both a Formula One car and an LMP1 car. He discussed the similarities with Top Gear, stating: “Compared to an F1 car, the first things you notice about an LMP1 car are the extra weight and the higher centre of gravity. It tests the driver and is perhaps a wee bit more challenging to drive. Certainly at Spa, Eau Rouge in an F1 car is easy flat, but you have to hold on to the 919 a bit more and our speeds are about 20-30kph down through the quick stuff

“Where [the 919] has the advantage is in the slow corners. An F1 car stops better, and the line and trajectory aren’t much different, but we maybe want to get the car turned in sooner so we can get back on the power… In La Source, we can really give an F1 car a run.

“You see F1 cars backing off and having to manage fuel reserves, we never have to do that – we’re flat out, all the way. The 919 is just awesome, the most advanced car I’ve driven, without a shadow of a doubt.”

The W06 has the speed advantage in the speed traps and into the corners, but the 919 Hybrid Porsche can get on the power earlier than the Formula One car, so gets a faster exit from slow and medium paced corners. But the suggestion from Mark Webber: if you want classic, wheel-to-wheel, pushing to the limits racing, then the WEC must be the way to look. Formula One can learn a lot from the endurance series, with being lighter on regulation restrictions being a key area to focus on if the spectacular racing that WEC can deliver is to be seen in the pinnacle of single-seaters.  

(images: topgear.co.uk)

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