@stefmeister Posted a video, in which we can hear strange noises from Buttons McLaren.
According to Sky’s Ted Kravitz, the strange noise is the engine running only half of the avaible 8 cylinders. As @hohum hinted these kind of devices are banned, but I have an interesting theory, why this could be legal. It might be a silly thing, but I would like to share it with you, and hear your toughts.
I think its operated by steering angle, when the driver turns the wheel fully to either side, the noise kicks in, using only 4 cylinders, reducing the torque output, but maintaining the same rpm, allowing the driver to hit power earlier out of the corner by reducing the wheelspin.
If it works like this, than its driver operated, and not an aerodynamic element, thus IMO legal. Of course it might be something else. Ideas?