720hp 919 Hybrid Evo – Faster Than F1
Porsche has stripped its 919 Hybrid race car of the restrictive appendages dictated by endurance racing regulations and let it loose around Spa-Francorchamps. Porsche works driver Neel Jani lapped the circuit in 1:41.770, that’s 0.783 seconds quicker than Lewis Hamilton’s pole position time set in qualifying for the 2017 Belgium Grand Prix. Jani’s time confirms that the 919 Hybrid Evo is quicker than a hybrid-era Mercedes F1 car – Jani achieved a top speed of more than 223mph.
The basis for the ‘Evo’ was the 2017 world championship car. It was fitted with developments that were prepared for the 2018 WEC season but never raced following Porsche’s withdrawal from the series at the end of 2017. Additionally, several aerodynamic modifications were made; a new larger front diffuser and rear wing were fitted, underneath the turning vanes and floor have been optimised with fixed height side skirts. The aero modifications resulted in 53 percent higher downforce. Interestingly the 919’s powertrain remained untouched.
The 919 is powered by a compact two-litre turbocharged V4-cylinder engine and two different energy recovery systems – brake energy from the front axle combined with exhaust energy. The combustion engine drives the rear axle while the electro motor boosts the front axle to accelerate the car with four-wheel drive. At the same time it recuperates energy from the exhaust system that otherwise would pass unused into the atmosphere. The electrical energy that comes from the front brakes and the exhaust system is temporarily stored in a liquid-cooled lithium ion battery.
The WEC efficiency regulations limited the energy from fuel per lap by using a fuel flow meter. At the 2017 championship round in Spa, in the Porsche 919 Hybrid’s final season, it could use 2.464-litres of petrol per lap. The V4 combustion engine’s output back then was around 500hp. Freed from these restrictions, equipped with updated software but running regular race fuel (E20, containing 20 percent bio-ethanol), the 919 Hybrid Evo delivers 720hp.
The amount of energy from the two recovery systems that could be used in Spa 2017 was 6.37 megajoule. This was by far below the systems’ potential. On his record lap Jani enjoyed a full boost of 8.49 megajoule – the e-machine’s output increased by ten percent from 400 to 440hp. To help further a four-wheel brake-by-wire system provided additional yaw control. Furthermore, the power steering was adapted for the higher loads and stronger suspension wishbones (front and rear) were implemented.
Compared to the car in race trim, the dry weight was reduced by 39 kilograms to 849 kilograms. To achieve this, everything was removed what isn’t needed for a single fast lap: air-conditioning, windscreen wiper, several sensors, electronic devices from race control, lights systems and the pneumatic jack system. Porsche’s multi-year tyre partner Michelin was immediately interested to work with a car that produces more downforce than a Formula One car. Keeping the exsiting tyre dimensions, the target was to increase the grip level significantly. Michelin developed new compounds to deliver the necessary grip with no compromise on safety.
Stephen Mitas, Chief Race Engineer LMP1, headed the project: “It was kind of an engineer’s dream come true for us”, the Australian admitted. “Having developed, improved and raced the car for four years, the guys had a very close relationship to it. We all knew, no matter how successful the 919 Hybrid was, it could never show its full abilities. Actually even the Evo version doesn’t fully exploit the technical potential. This time we were not limited by regulations but resources. It is a very satisfying feeling that what we’ve done to the car was enough to crack the Formula One record.”
The record lap was the first appearance on the 919 Tribute Tour. It can next be seen doing a demo lap on the legendary Nordschleife before the start of the 24-Hours Nürburgring race on May 12. Drives at the Goodwood Festival of Speed (July 12 to 15) and the Festival of Porsche in Brands Hatch (September 2) will follow as well as the car’s participation at the Porsche Rennsport Reunion in Laguna Seca, California (September 26 to 29).