France's Romain Dumas, driving the No. 7 Penske Racing Porsche RS Spyder LMP2 prototype, pulled side-by-side and then passed the Emanuele Pirro/Marco Werner Audi R10 TDI LMP1 car with four laps remaining to win Porsche's eighth straight American Le Mans Series event overall at the Detroit Belle Isle Sports Car Challenge presented by Bosch on Saturday.

With the Penske Porsche victory and the Dyson Racing Porsche's Butch Leitzinger/Andy Wallace second place in LMP2, Porsche clinched the LMP2 engine and LMP2 chassis manufacturers' championship for 2007, adding to the Penske Racing team championship, which was decided last week at Mosport.

Dumas, and co-driver Timo Bernhard of Germany, started behind their Penske Porsche teammates, Australia's Ryan Briscoe and Germany's Sascha Maassen, but Briscoe ran into trouble early, incurring a penalty for avoidable contact with a GT2 car that handed the lead to Bernhard. But, after a series of pit stops, Briscoe put himself back into the lead before handing the car over to Maassen with 90 minutes remaining.

Meanwhile, after a yellow flag session, the Pirro/Werner Audi jumped into the lead at the re-start, and it looked like the more powerful diesel race car would break the Porsche overall win streak. Dumas, however, chased him down with less than 3 minutes to go.

"The Audi could pull away on the two long straights, but I could get close at the short corners," Dumas said. "I did not want to risk my LMP2 first position, but I found a place to pass. He then passed me back, but I caught him again at the next corner. I knew I could turn faster laps, but it was hard to get past him because of traffic and his power out of the corners."

Maassen ran into bad luck late in the race as one of the Acuras spun and knocked off the No. 6 car's rear spoiler, causing an unscheduled pit stop. That put the No. 6 two laps back, resulting in a seventh-place finish in Class. Although Bernhard/Dumas have not clinched the LMP2 driver championship, they are 37 points ahead of Briscoe/Maassen with only 49 points to be earned in the last two events.

The series next event is Oct. 6 at Road Atlanta with the season finale Oct. 20 at Laguna Seca.