Recently, three Mazda6 sedans equipped with 173 horsepower 2.2 liter SkyActiv-D diesel engines established a new speed record for diesel powered production cars. Running in a 24 hour marathon at the ATP testing track in Papenburg, Germany, the fastest car averaged 137.368 mph during the 24 hour test with the other 2 cars less than 1 MPH behind. That’s almost 7 mph faster than the old record for diesel powered production cars between 2.0 to 2.5 liters.

The three Mazda 6 diesels were driven by 23 drivers from 7 European countries. Most of the drivers were professionals or journalists, but several were car enthusiasts selected from a pool of applicants back in May of this year. During their 1.5-hour stints behind the wheel, the drivers were not allowed to follow in the slipstream of a preceding car and needed to be “exceptionally careful” in the steeply banked curves at each end of the oval to avoid losing speed.

During the marathon event, the three Mazda 6 diesel sedans also set several other average speed records over a variety of distances. The cars were crewed by volunteers from Mazda dealerships all across Europe.