The Intercontinental GT Challenge will expand into a four-round championship next year, with the addition of an eight-hour race at Mazda Raceway Laguna Seca, as a joint event with Pirelli World Challenge.

The event, scheduled for Oct. 14-15, will be eligible to GT3 and GT4 machinery, and although not being a points-paying PWC round, is expected to feature a large mix of cars from the series.

According to SRO Motorsports boss Stephane Ratel, an environmental restriction at the California circuit has limited the race to eight hours, which is believed to be the first of its kind in professional sports car racing.

“The idea would be to run another series in Pirelli World Challenge, like TC, in the morning to start,” Ratel told Sportscar365. “Then you can go straight onto an eight-hour race, which would be from 10:30 a.m. to 6:30 p.m., or something like this.

“It’s the longest we could have because we don’t have the authority to go longer than this.”

Laguna Seca joins the Liqui Moly Bathurst 12 Hour, Total 24 Hours of Spa and Sepang 12 Hours, which remains on the schedule for next year, with hopes of expanding to a fifth round in South Africa in 2018.

“We have 24 hours, we have 12 hours, we have eight hours and hopefully one day we have a nine-hour race,” Ratel said.

GT Challenge, which launched this year, is largely a manufacturer and driver-based series, with the vision of utilizing local teams and equipment for each round.

This year’s inaugural season features manufacturer involvement from McLaren, Audi, Mercedes and Bentley.

“Like I said, the idea is not to transport teams across the globe,” Ratel added. “It’s to use local teams and to fly engineers and drivers.

“Laguna Seca is definitely the place to do it. It has the heritage, it has the glamour. It’s good.”

2017 Intercontinental GT Challenge Schedule:

Feb. 4-5 — Bathurst 12 Hour

July 29-30 — Total 24 Hours of Spa

Oct. 14-15 — Mazda Raceway Laguna Seca (8 Hours)

Dec. 9-10 — Sepang 12 Hours