The second weekend in June seems to come around quicker and quicker every year, and with it come the Le Mans 24 Hours – the jewel in the crown of sportscar racing and this year the headline event of the Intercontinental Le Mans Cup (ILMC).

While the Automobile Club de l'Ouest's new championship may have brought bigger grids and greater prestige to some events included in the calendar, the difference it makes to the Grand Prix de l'Endurance is minimal. The same teams remain, and of course the famous race remains untouched and the LMP1 machines are still those almost certain to include the overall winner and they are still lead by the diesel powered Peugeots and Audis

The differences brought about by the new for 2011 regulations, however, are felt far more by the LMP1 ranks.

Both diesel works teams bring new cars to Le Mans this year. Peugeot's 908 brings simpler nomenclature in what – outwardly – appears to be an evolution of their old car while Audi's R18 is a revolutions for the Ingolstadt team as it sports a closed cockpit, a decision brought about by the new regulations.

Also obvious from the first glance at the cars is the new shark fin, mandated on the new designs in an effort to cut down on the 'blow over' accidents that have blighted the Prototype entries at ACO rules races in recent years.

However, the real change is under the bodywork. Engine size is reduced dramatically – the R18 is pushed along by a 3.7 litre V6 compared to the R15's comparatively brutish 5.5 litre ten-pot unit. It must be said that the same regulation changes have affected the petrol fuelled cars Audi and Peugeot share the LMP1 class with. On the showing of two races – the 12 Hours of Sebring and 6 Hours of Spa-Francorchamps – the performance chasm between the competing fuels remains despite the best efforts of the ACO, and with the withdrawal of Highcroft Racing's HPD ARX-01e went the only petrol car that could realistically have hoped to spring a surprise.

Barring the sort of occurance planets have to align to create the LMP1, and overall, winner will be one of the six works cars – three from each of the manufacturers.

Works Peugeot and Audi will fight at the front, ORECA will take advantage of their problems

Among the driving line-ups (the class entry list can be found at the bottom of this article) there is little to choses between the teams, and in the one race where the R18 and 908 have faced each other it was the French squad who won.

But it was the same story twelve months ago, but when it came to Le Mans all the Peugeots were struck by mechanical failures, including a hat-trick of engine failures caused by the same part. That part was quickly replaced, Peugeot Sport using a stronger material when they ran at Silverstone, Petit Le Mans and Zhuhai at the end of last year – winning all three races.

Both cars are extensively tested, but the Peugeot made it's race debut in March at Sebring, Audi waiting until Spa to debut the R18, but with so much testing, the two month difference is of little significance.

It really is too close to call between the two manufacturers. The reliability level – almost unthinkable even a decade ago – means that the 24 Hours can almost be considered a sprint race. Gone are the days of hare and tortoise tactics designed to break rivals. The problems, when they do come, no matter how small will decide who wins the race.

And, if all six 2011-spec cars encounter problems expect the ORECA Matmut privateer Peugeot 908 HDI FAP (older car, longer name) to pick up the pieces. Hughes de Chaunac's team won the 12 Hours of Sebring when the works car – only four of them on that occasion – hit mechanical problems (and each other).

Behind the seven diesels the quest for the unofficial honour of best petrol car is likely to be a four way fight thrown wide open by Highcroft's absence.

In past years the petrol win has been the natural domain of Aston Martin Racing. However, the off-season culling for the Lola-Aston coupe in favour of the all Aston Martin AMR-One, has brought nothing but problems. Initially aiming for a race debut at Sebring, the race debut was delayed until the Paul Ricard Le Mans Series opener, which the lone entry failed to finish.

The AMR-One has endured a troubled debut season, yet to finish a race and blighted by engine woes

Problems, and a program concentrated on Le Mans, meant the team withdrew from the Spa-Francorchamps race in favour of further development, which the team claim has improved the reliability of the car's straight-six turbocharged engine. It is however, not expected to have improved to the extent needed to finish Le Mans, let alone fight towards the front of the field.

The Aston Martin baton for petrol honours has been picked up by Kronos Racing and the Marc VDS run Lola-Aston Martin. Both organisations have success – Kronos ran Sebastien Loeb to the 2006 WRC title, while the Belgian Marc VDS squad can be found in FIA GT1 competition and in the Moto2 paddock. They also raced at Le Mans last year with their GT1 Ford GT, but an early crash put them out of the race.

The team's GT1 drivers Maxime Martin and Bas Leinders join Vanina Ickx, seamlessly moving with the car from Signature Plus to set up an all-Belgian driving squad.

Petrol opposition will come from Rebellion Racing, OAK Racing and Pescarolo Team.

No matter what team you're supporting, or what flag you're camping under, if you love Le Mans you'll have a place in your heart for Henri Pescarolo. He is almost synonymous with the Le Mans 24 Hours, first as a driver then with his Pescarolo Sport team, which was based on the track's Technopark. However, financial problems forced Pescarolo to give up his team, the assets set to be auctioned off.

Only the generosity of buyers – including OAK Racing owner Jacques Nicolet – could give Henri back his team. Using an updated version Pescarolo 01 chassis as appeared in 2009, and with an all-French (what else would you expect from Pescarolo?) led by Emmanuel Collard they are the sentimental favourites for petrol victory. That sentimentality is backed up by an overall win to start the year at Paul Ricard followed by sixth place at Spa behind five diesels.

Rebellion Racing are likely their biggest challengers on paper. The Toyota engines in their Lola Coupes have the power and their drivers have the ability, but Rebellion entries in the past have be blighted by errors behind the wheel, none more vivid that JeanChristophe Boullion depositing him car in the Ford Chicane gravel during the night last year.

OAK Racing have an enviable record at Le Mans, but the step up to LMP1 is a much harder challenge than LMP2

OAK Racing are stepping up to LMP1 this season, and though they have a tremendous record of podiums in LMP2 they face far, far tougher competition in the premier class. As has become the norm for the team their two LMP1 entries are split. The no.15 is packed with professional talent, including one time F1 man Tiago Monteiro, while the no.24 includes team owner Nicolet and JeanFrancois Yvon – the most experienced man at Le Mans this year.

Unlikely to be in contention for any honours is the Hope Racing Hybrid, the beneficiary of a scheme by the ACO to bring new technology to Le Mans. Despite a strong driver line-up, the Swiss team's ORECA 01 is unlikely to see the checkered flag. Cynics might say the hours of darkness is pushing it.

2011 Le Mans 24 Hours – LMP1 Entry List

No.1 – Audi Sport Team Joest – Audi R18 TDI – Timo Bernhard-Romain Dumas-Mike Rockenfeller
No.2 – Audi Sport Team Joest – Audi R18 TDI – Marcel Fassler-Andre Lotterer-Benoit Treluyer
No.3 – Audi Sport North America – Audi R18 TDI – Dindo Capello-Tom Kristensen-Allan McNish
No.5 – Hope Racing – ORECA 01/Lehmann – Casper Elgaard-Jan Lammers-Steve Zacchia
No.7 – Peugeot Sport Total – Peugeot 908 – Anthony Davidson-Marc Gene-Alex Wurz
No.8 – Peugeot Sport Total – Peugeot 908 – Nicolas Minassian-Franck Montagny-Stephane Sarrazin
No.9 – Team Peugeot Total – Peugeot 908 – Sebastien Bourdais-Pedro Lamy-Simon Pagenaud
No.10 – Team ORECA Matmut – Peugeot 908 HDI FAP – Loic Duval-Nicolas Lapierre-Olivier Panis
No.12 – Rebellion Racing – Lola/Toyota – Jeroen Bleekemolen-Neel Jani-Nicolas Prost
No.13 – Rebellion Racing – Lola/Toyota – Andrea Belicchi-Jean-Christophe Boullion-Guy Smith
No.15 – Oak Racing – Oak Pescarolo/Judd – Tiago Monteiro-Guillaume Moreau-Pierre Ragues
No.16 – Pescarolo Team – Pescarolo/Judd – Emmanuel Collard-Julien Jousse-Christophe Tinseau
No.20 – Quifel ASM Team – Zytek 09SC – Miguel Amaral-Warren Hughes-Olivier Pla
No.22 – Kronos Racing – Lola-Aston Martin – Vanina Ickx-Bas Leinders-Maxime Martin
No.24 – Oak Racing – Oak Pescarolo/Judd – Richard Hein-Jacques Nicolet-Jean Francois Yvon
No.007 – Aston Martin Racing – AMR-One – Christian Klien-Stefan Mucke-Darren Turner
No.009 – Aston Martin Racing – AMR-One – Adrian Fernandez-Andy Meyrick-Harold Primat