Porsche Delay RS Spyder Debut

Instead the car will undergo more testing before a decision is made if it will compete in its maiden race in the final round of the American Le Mans Series at Laguna Seca a fortnight later.

The return of multiple Le Mans 24 hours winners Porsche to sportscar racing was highly anticipated, when it was announced earlier this year that the crack team Penske Racing would run the customer cars in ALMS in 2006.

"Any completely new race car requires a considerable amount of testing to acquire performance and durability," said Hartmut Kristen, director of motorsport for Porsche AG.

"By now, our car has the speed, but not the stamina to finish a 1000-mile race like Petit Le Mans. We hope, with the additional planned testing by Penske Motorsports, it will be ready to make its test race debut at the four-hour Laguna Seca contest."

The Porsche RS Spyder features a new Porsche engine, transmission, and chassis, all incorporating the latest in Porsche automotive technology and created to conform to new 2006 regulations of international sanctioning body Automobil Club de l'Ouest.

Petit Le Mans organisers have been quick to dismiss concern over any possible loss of enthusiasm for the event now that Porsche has withdrawn.

ALMS president Scott Atherton said: "It is disappointing for sure, but not completely unexpected. The development of a new race car is a daunting task under ideal circumstances, and revisions to test schedules are very common.

"Let's face it. It is an extremely difficult race for a fully developed car. So for anyone close to the sport, it is understandable that Porsche has revised its plans."