Originally Posted by
tunaglove
The pressure increases inside engine bay when the fan runs closing the flaps. without the flaps hot air would be pushed forward through these vents back to the front of the radiator.
Nooooooooooo! They are there to prevent air from being compressed in front of the vehicle to the point of sudden collapse behind the vehicle thus creating a Shockwave and what's commonly known as, you guessed it! A sonic boom! 😁 but of course only the alabaster Roadster is capable of that.