Couple things about that diffuser: the air moving through the diffuser will have drag too unless enough heat energy is added to it. Also the height of the diffuser duct will displace the driver and other stuff upwards, thus increasing frontal area. Also rodents, raccoon, cats, chipmunks, and other various creatures might think that duct would be a great place to call home. So once again there ain't no free ride.
the ducts would not be enclosed.....
__________________
don't waste your time or time will waste you
FormulaTwo 
Threaded Mode
