The Japan Automobile Federation (JAF) released as part of their 2017 racing calendar and technical regulations, the revised technical regulations for the 2017 Autobacs Super GT Series.
The most significant changes detailed include anticipated downforce cuts to the GT500 cars from 2017 – done primarily in the name of safety on the series’ smallest venues.
Crucially, the height of the rear diffuser on all GT500 cars has been reduced from 206 millimeters to 101 millimeters, a reduction of over 50 percent. By lowering the height of the rear diffuser, the amount of downforce generated underneath the car, as well as the amount of turbulent air generated from the rear of the car, will be reduced dramatically.
In addition, the width of the standard rear wing will be extended, from 1,390 millimeters to 1,900 millimeters – the same width as the low-downforce spoiler used at Fuji Speedway, effectively making it the new standard spoiler for all circuits on the calendar.
The length of the front splitter has also been reduced, from 100 millimeters down to 50mm.
JAF-GT300 specification machines, including Mother Chassis platform cars, will also see general air restrictor size reductions across the board.
The way it’s trending, the lap records set on most Super GT circuits by the GT500 class may stand for several years after the downforce reductions are put into place.
On the other hand, wholesale downforce reductions in the NASCAR Cup Series this year have resulted in improved racing action in 2016 – and it would certainly produce the same effect in Super GT, while accomplishing the primary goal of reducing speeds at tracks like Sportsland Sugo and Okayama International Circuit on safety grounds.