Cup Series to go green in '07.

The NASCAR Nextel Cup Series will use unleaded fuel in every race bar the Daytona 500 next season, one year earlier than planned.

After successful tests with unleaded petrol in both the Busch and Craftsman Truck Series this year the 2007 season-opening race will be the last run on traditional 'four star' petroleum with the remaining 35 races and the All Star Challenge running on Sunoco's unleaded variety.

With the Busch Series reporting no noticeable increase in engine and mechanical problems following their 'green' races, series bosses felt that it was pointless to put off the inevitable switch, especially as the issues of caring for the environment are currently a pressing issue in the US.