Theory about airflow dynamics for scoop for ASP medium IC
 

I have the front bumper off of my car and found that its a good time to cut/fit the scoop for the intercooler onto the car.

Looking at how it would fit I noticed that the "top" is exposed as there isn't a barrier for the air on the top of the scoop allowing the air to escape...so instead I may fiberglass a top.

However, is there any flow benefit if I make the opening of the scoop bigger? That is the scoop would go big to the smaller restriction then back to the bigger opening.

If the smaller opening is the main area of flow restriction, just having the scoop may be all that is necessary to help "guide" the air and no enlargement of the intial opening is necessary???

I think a properly designed scoop is all that is necessary. Otherwise I think you may end up robbing some airflow from the radiator, as the radiator opening in the bumper isn't that big to begin with.

For a school project, my friend and I were designing a new air duct for our formula car project team, and we consulted a fluid dynamics prof about this. He said a reason why formula cars have diffusers (smaller opening to bigger opening) could be that it allows the airflow to slow down in the diffuser before it reaches the heat exchanger, so it evenly distributes across the surface, making for a better efficiency.

A bigger opening to smaller opening would act somewhat like a nozzle, speeding up the airflow through the heat exchanger though. So I would think that would make it more efficient, but I'm not sure.

It would only speed it up at the choke point, like a venturi effect; once the airflow expands out to cover the IC surface area, it will slow sufficiently to allow adequate coverage and heat exchange from the IC. The diffuser effect is not so much for even distribution as it is to allow the airflow to slow enough for the heat exchanger to work properly.

I'd think that only if the front intake portion was really long (as in maybe twice as long as the rear portion) and/or seriously wide would it have a bad effect.

According to the Corky Bell turbo book, the best is to go smaller then larger because the air gets trapped inside. If you go large to small, the air can revert and not got through.

Thanks neit!!

I cut the duct and it looks perfect! I got lucky in eyeballing it and slowly dremeling pieces off.

post pics! :D

I would if I could! I had a hard drive crash on my main computer and I am using my old 486 to surf the web. I don't have the software to get the pics from the camera....I think.

I'll still take pics but post them later. There isn't much to the cuts, but I plan to rivet the aluminum top on it and paint the whole thing an even black. Also I want to try to find some edge foam like what is on the intercooler duct to act as a seal....

Off to Home Depot!