Le Mans organiser the ACO has released the technical regulations for the 2010 Le Mans 24 Hours and Le Mans Series.
The governing body's efforts to equalise the performance of the diesel and petrol-powered LMP1 class continues with the diesels pegged further back and the petrol cars granted a slight power increase.
The rules regarding the bodywork of prototypes have also been tweaked, although the final regulations on front bodywork - which was the area of dispute between Audi and Peugeot at this year's Le Mans - is still to be finalised.
Vincent Beaumesnil, ACO sports manager, said: "Our role is to define a fair set of regulations to give each configuration the opportunity to race. In an unfavorable economic context, the idea was to modify the cars as little as possible. All entrants want to be able to use their current cars in 2010, and possibly in 2011 and beyond.
"It was necessary to make a few clarifications, and to modify certain points in the regulations, to prevent some entrants from investing in solutions that we consider too extreme, and which go against the aims we have set ourselves - to keep laptimes above 3m30s at Le Mans."
The changes to the rules follow a meeting with between the ACO and the manufacturers at Le Mans in June to analyse data from this year's race.
"Regulations must evolve from one year to the next to adapt to the context," added Beaumesnil. "When you publish them, entrants interpret them, work on them, find solutions and performance increases just at the moment when we have to prevent performance escalation to guarantee a level playing field and safety."
A summary of the ACO's regulation changes
1- LMP1 and LMP2 bodywork:
At the rear:
Closing of the part behind the rear wheels. The use of grills or fairings to cover the rear wheel above the axis of the axle will no longer be allowed. The bodywork must be closed in this area and must carry the rear lights, rear stop lights and indicators.
On the sides:
Bodywork located at the rear of the axis of the rear wheels and above the reference plate must form a smooth, continuous, unbroken surface of convex form only, without cuts. It must not be set back more than 100mm in relation to the width of the bodywork at the axis of the rear axle (measured horizontally).
At the front:
Confirmation within 15 days of the aerodynamic definition of the front of the cars. It is currently under study and consultation with the manufacturers taking into account the technical feasibility and cost issues.
2- LMP1 engines
Diesel restrictor reduced from 37.9mm to 37.5mm
Restrictor advantage for closed cars reduced from 0.4mm to 0.3mm
Supercharger pressure reduced from 2750 to 2590 mbar
Petrol restrictor increased from 32.5mm to 33.3mm
GT1 engine (Aston Martin) restrictor increased from 32.7mm to 33.3mm
Use of engines in the Le Mans Series:
At present the regulations oblige entrants to use the same engine for two consecutive In 2010, three sealed engines can be used freely during the season.
Weight of the cars:
The minimum weight of the LMP1 diesel cars is increased to 930kg (30kg of ballast cancelled). The minimum weight of the other categories remains unchanged.
The full ACO regulations can be read, here.