It’s a case of Audi vs Audi this weekend, as the second round of the new FIA World Endurance Championship takes place at Spa-Francorchamps.

The six-hour race, which begins at 2.30pm local time on Saturday, will open an exciting new chapter in sports car racing history. It has been 20 years since a genuine endurance world championship race was held in Europe. But more significantly, the Spa encounter will herald the start of an era of technical innovation that will not only change the face of the sport, but also have a direct impact on the cars we drive on the road.

Audi’s R18 e-tron quattro hybrid will make its race debut on Saturday in what will be a useful performance indicator for the big one – the Le Mans 24 Hours, in June.

Sadly, there is a faint whiff of anti-climax here at Spa, because while the e-tron’s maiden appearance will be fascinating to witness, the much-anticipated face-off with the rival Toyota TS030 HYBRID will have to wait. A wet-weather testing crash at Paul Ricard caused by water contamination in a control box has set back the new programme. Toyota must now face the daunting prospect of giving its new car a race debut at Le Mans.

Fortunately, there is enough interest surrounding Audi to stop this significant race becoming a damp squib – whatever the fickle Ardennes weather might bring come the weekend.

As they will at Le Mans, the two e-trons will take on a pair of R18 Ultras, updated versions of last year’s La Sarthe winner that do not run with the flywheel hybrid system developed by Williams. The hybrid R18s should have a pace advantage over their sisters thanks to the power boost to the front wheels (hence the return of ‘quattro’ to racing), but there’s not much in it so far over one lap.

In the second of Thursday’s pair of free practice sessions, the two e-trons of 2011 Le Mans winners Marcel Fassler, Andre Lotterer and Benoit Treluyer, and the veteran crew of Allan McNish, Tom Kristensen and Dindo Capello, shaded the two Ultras – but there was only eight-tenths of a second separating the four cars. The quartet might be from the same team, but make no mistake: they will be racing each other as Saturday afternoon turns to evening.

What could decide the race, besides reliability and incidents with slower cars, will be the efficiency of the hybrids. We all want to know, how long can they run on a full tank of fuel with the savings that come with the flywheel hybrid system?

“The hybrid is a solution to run longer with the same amount of energy,” said Audi Sport boss Dr Wolfgang Ullrich in the press conference on Thursday. “The main target is always to go quicker. But the question is do you go for more power or go longer on the same amount of fuel?”

We’ll get some idea this weekend, but we’ll have to wait for Le Mans for the full answer when Toyota turns up with its super capacitor system. The Japanese giant has chosen a different route to Audi, seemingly going for the ‘more power’ option. Which will be best? We can only surmise, but for a detailed analysis of the pros and cons of the hybrid choices, read Gary Watkins’ feature in the June issue of Motor Sport.

Beyond the hybrid headlines, the Spa race promises much more with an impressive entry of petrol LMP1s – including the svelte new Pescarolo-run Dome-Judd, which takes its bow this weekend in the hands of Nicolas Minassian and Sebastien Bourdais. A healthy grid of LMP2 ORECAs, Lolas, Zyteks and HPDs will add further depth, while the GTE Pro and Am hordes will be fighting out their own battles, as usual.

One way or another, history will be made on Saturday afternoon, as a new era begins. Can Audi’s e-tron hybrid kick it off with a bang by scoring a debut win?