I have about 6 of these fans at my home in karachi, Ive shown Dani80pk how much air they move.
All the ones I have are 13 inch in diameter with heavy duty motors. When installed in Khyber, margalla or any japanese car etc, they are wayyy louder than the engine itself at idle. and if you are wearing loose clothing - you should stay away from the bumper as it will pull them into its blades.