,
I made the ‘cut’ a bit narrower than the snorkel along with placing it a bit forward. Remember, you can always cut more material, but you can’t add it back.

With the first cut made, I used some more C.A.D to get the slope of the hood.
Next, I made another cut and some more cardboard to get the slope of the hood in the fore-aft direction.
With the two pieces of cardboard, some engineering paper, and some calipers, I had the slope of the hood.
Plug in the main values into the handy dandy spreadsheet….
Do a little 3D modeling…
And voila! (A good chunk of change later…) A rapid prototyped NACA duct out of PC-ABS. Now, I needed to make the big cut in the hood. I used some more paper and a pen to get the outline of the opening of the duct.
8 comments
No, I only made the one. If you decide to go this route, you should also stick a one-way check valve in the air hose going from the intake to the front breather on the valve cover. I was losing ram air boost through this flow path. I regained the lost boost after plugging it in later testing. A one-way valve is a more elegant solution.
https://motoiq.com/project-s2000-part-22-testing-new-goods-and-more-intake-mods/2/
No, I only made the one. If you decide to go this route, you should also stick a one-way check valve in the air hose going from the intake to the front breather on the valve cover. I was losing ram air boost through this flow path. I regained the lost boost after plugging it in later testing. A one-way valve is a more elegant solution.
https://motoiq.com/project-s2000-part-22-testing-new-goods-and-more-intake-mods/2/
No, I only made the one. If you decide to go this route, you should also stick a one-way check valve in the air hose going from the intake to the front breather on the valve cover. I was losing ram air boost through this flow path. I regained the lost boost after plugging it in later testing. A one-way valve is a more elegant solution.
https://motoiq.com/project-s2000-part-22-testing-new-goods-and-more-intake-mods/2/
No, I only made the one. If you decide to go this route, you should also stick a one-way check valve in the air hose going from the intake to the front breather on the valve cover. I was losing ram air boost through this flow path. I regained the lost boost after plugging it in later testing. A one-way valve is a more elegant solution.
https://motoiq.com/project-s2000-part-22-testing-new-goods-and-more-intake-mods/2/
No, I only made the one. If you decide to go this route, you should also stick a one-way check valve in the air hose going from the intake to the front breather on the valve cover. I was losing ram air boost through this flow path. I regained the lost boost after plugging it in later testing. A one-way valve is a more elegant solution.
https://motoiq.com/project-s2000-part-22-testing-new-goods-and-more-intake-mods/2/
No, I only made the one. If you decide to go this route, you should also stick a one-way check valve in the air hose going from the intake to the front breather on the valve cover. I was losing ram air boost through this flow path. I regained the lost boost after plugging it in later testing. A one-way valve is a more elegant solution.
https://motoiq.com/project-s2000-part-22-testing-new-goods-and-more-intake-mods/2/
No, I only made the one. If you decide to go this route, you should also stick a one-way check valve in the air hose going from the intake to the front breather on the valve cover. I was losing ram air boost through this flow path. I regained the lost boost after plugging it in later testing. A one-way valve is a more elegant solution.
https://motoiq.com/project-s2000-part-22-testing-new-goods-and-more-intake-mods/2/
I’d be interested if you made a cf naca duct!