THE ROOT OF THE SUPERCAR CONTROVERSY
The influence of a road car on the track isn’t universal within closed-cockpit racing. Like the DTM, Australian Supercars also employs a common spaceframe chassis. But the carry-over from car to car extends further than that: the floorplan is identical across the grid.
To fit the common dimensions, the newfor-2019 Mustang has been stretched and its roofline raised. That means its dominant form – winning 11 of the first 12 races this season – isn’t derived from the Mustang in the dealerships. If that was the case, the rival Holden ZB Commodores and Nissan Altimas would rely on front-wheel drive.
“[Supercars] is a completely different championship,” says Holden engineer Carl Faux. “The cars in TCR or British Touring Cars are based on the road car shells. Supercars has got a common chassis, they brought that in for 2013.
The chassis themselves – the floorplan, the cage – is identical in every single car. That means it’s effectively a silhouette formula. They have no DNA in the chassis of what the road car is.”
The Mustang’s box-fresh pace has instead flowed from its superior aerodynamics. Although it was declared legal at the start of the season, the one-sided nature of the results has led to a review. To bring about parity, the size of the Mustang’s rear-wing endplates have been reduced to reign in its mid-corner performance.
As Faux adds, given the procedure for testing the aerodynamic capabilities in Supercars, the miscalculations that led to the performance disparity aren’t very surprising.
“They do straightline testing [in Supercars] where they measure the downforce and the drag and equalise those. You’ve got a downforce number that you’ve got to hit – it’s up to the homologation team to decide whether they want to put that distribution front or rearward. But that procedure is only in a straight line – it has no effect on what it does in the corners. You don’t pick up the big endplates.”
But it’s not all bad, because at least the Mustang used Down Under shares something of a resemblance to the one customers can take home themselves.
“Obviously to get the Mustang in, they’ve had to change pretty much everything to make it happen,” concludes Faux.
“In fairness, it looks more like a Mustang than the NASCAR version does…”