Audi and Toyota are unconcerned by Porsche's early test debut with its 2014 Le Mans 24 Hours contender.
The Porsche petrol-powered LMP1 hybrid became the first car built to the new-for-2014 rulebook to run when it hit the track at the start of last month, which is likely to give it a head-start of a minimum of four months over its manufacturer rivals for next year's World Endurance Championship.
Audi is not expecting its 2014 contender to run until the autumn, while Toyota has yet to set a date for the first run of its second-generation P1 car.
However, both argue that their presence on the race track with existing hybrid contenders means that they have no worries about the Porsche's early debut.
Audi Sport boss Wolfgang Ullrich pointed out that Porsche needed to be on track earlier because it will be playing catch-up ahead of its return to top-line sportscar racing next season.
"If you are coming back into a category, you need to start stuff much earlier," he said.
"Porsche is coming back to prototype racing after many years away. I think it is very much an interim car and not the car they will race."
Toyota Motorsport technical director Pascal Vasselon put forward a similar viewpoint.
"Considering they are not racing, this is what they have to do: to be very early to be able to get as much experience as possible with their new design," he explained.
"Our 2014 car will be new, but in terms of aero and hybrid development, there is a lot of continuity with this year's car.
"Porsche has started from zero, so they need more time. We are not starting from zero."
Ullrich stressed that Audi was happy with the timescale set for the first tests of its new 2014 design.
"We have started development and we are in a timescale that fits," he said.
"We will run in the autumn. That is a bit earlier than in past years because it is a new concept and needs a little more testing."
Audi tested an existing R18 e-tron quattro running next year's narrow tyres at the Le Mans test day earlier this month in what was billed as a data-gathering exercise for Michelin.
Vasselon could not say whether the new Toyota would run this year or early next.
"It is too early to tell at the moment," he said. "Because of our limited resources, we had to tackle 2013 before attacking '14; now our design crew is 100 percent on the 2014 car."
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