WOT: aerodynamics and object on cop cars, Who's right, me or co-worker? Options

[914rrr]

A new product / electronic device my employer is developing is packaged in an aluminum enclosure that is roughly 10'' square. One intended use for this product is a mobile application, mounted to the roof of vehicles like police cars.

I say that the enclosure needs to be sustantially smaller and more aerodynamic, and that it would create substantial aerodynamic drag which could limit top speeds. I also have visions of it breaking loose from the the roof of a vehicle at speeds in excess of 100 MPH.

My co-worker / project manager says that the size of the device is fine and that a 300 HP cruiser will hardly notice the difference.

Who's right?

[bondo]

Light bars are bigger than that. But then they have been getting smaller and more aerodynamic, probably for a reason.

The real answer is anything that adds to the cross sectional area of a car will increase drag, reducing top speed. How many horsepower is irrelavent. The top speed is where you've run out of horsepower, and increasing drag will make you run out sooner.

The real question is: By how much? And how much is OK? How much is too much?