Revamped regulations for the 2014 World Endurance Championship (WEC) have placed new emphasis on hybrid drive models and energy efficiency. This high-speed clash of cutting-edge hybrid technologies has seen all eyes fixed firmly on three mainstays of automotive engineering: a resurgent Porsche, the all-conquering Audi and hybrid trailblazer Toyota. The latest event took place on the weekend at the 6 Hours of Spa-Francorchamps in Belgium, with the TS040 Hybrid outperforming and outlasting its counterparts to secure the Toyota team its second victory in as many starts. The battle of the hybrids is on!

Following a 16 year absence, Porsche has returned to the fold and is looking to re-establish its legendary status in endurance racing. It is fielding two teams in its two liter V4 919 Hybrid, an engine of around half the capacity of its rivals. With a single turbo charger, the 919 features two separate energy recovery systems. The first harnesses thermal energy from the exhaust gases using an electric generator, the energy then driving the front wheels through a differential, in effect affording the 919 a temporary all-wheel drive system. The second converts kinetic energy from braking into electric energy to be stored in water-cooled lithium-ion battery packs.

Driven by Neel Jani, the no.14 Porsche started from pole position at the 6 Hours of Spa and set the pace early. After leading the initial part of the race, electrical problems struck and caused a three-lap pitstop, the team ultimately taking the checkered flag in fourth position. The second of Porsche's 919's would suffer even further technical problems involving rear dampeners and a drive shaft failure, finishing 23 laps behind the leaders.

Audi has dominated the endurance racing landscape since 2000, a time-frame which just happens to coincide with the duration of Porsche's absence. Its more recent successes include the 2013 WEC title and a win in the pinnacle of endurance motor racing, the 24 hours of Le Mans. The company is looking to replicate its exploits of 2013 and has put three teams in its redesigned R18 e-tron Quattro. The rear wheels of the all-new R18 are powered by a 3.7 liter V6 TDI mid-engine with an electric turbocharger. The car's first hybrid system is hooked to the front axle, while a second recovers thermal energy from the exhaust gases and redirects it to flywheel storage system. The flywheel storage also holds energy recovered during braking and is designed to deliver extra power to the front axle motor or electric turbocharger for better acceleration.

The no.1 R18 e-tron quattro driven by Lucas di Grassi, Tom Kristensen and Loic Duval, nabbed a second place finish at the 6 hours of Spa. The latter part of the race saw Duval trailing two Toyota TS040s, until a late pitstop by the second-placed Alex Wurz allowed the no.1 Audi to slide into second, finishing 6.9 seconds ahead of Wurz, but over a minute behind the first placed Toyota. Audi's second and third R18s finished in fifth and sixth place respectively.

Toyota has surpassed the expectations of most by winning several races during its first two seasons of competition. Suffice to say, opening its 2014 WEC campaign with back-to-back wins has been a dream start for the world's largest hybrid manufacturer. It is fielding three teams in its 3.4-liter V8 TS040, which stores energy in a Nisshinbo supercapacitor and features an Aisin AW motor-generator on the front axle and DENSO unit at the rear to deliver four wheel drive.

The team of Anthony Davidson, Nicola Lapierre and Sebastien Buemi has been dominant in the year's first two WEC events. The first race at Silverstone saw the trio finish one lap ahead of stablemate Toyota no.7, followed by a 1 minute 13 second victory ahead of Audi's R18 at Spa. Such a comprehensive victory six weeks out from the Le Mans, over last year's winning car nonetheless, is sure to fill the Toyota team with hope that it can feature on the podium at La Sarthe on June 14.

We'll be keeping an eye on Le Mans and the WEC events to follow to learn more about the strengths of the different technologies, which will no doubt filter through to our everyday vehicles. In the meantime, you can click through to the gallery to browse the action from the weekend's race at the spectacular Spa-Francorchamps racetrack in Belgium.

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