Such a long walk down this thread and still no photograph with the cowling removed, no sense of where anything is. The scoops look like they capture air into the cowling, but then the exhaust looks restricted in comparison and has some difficult route to pass air over anything inside the cowling.
In other heat transfer systems I've seen, they are designed to allow air to bypass the item that generates heat; usually a big problem with finned heatsinks as even a small gap over the tops of the fins is a far less restrictive path than it is through the fins.
In cars there are often fan shrouds to seal the entire radiator to force all the make-up air ejected by the fan to go through the radiator rather than bypassing from under the car.