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NACA Duct vs Hood Scoop?

Old 05-03-13, 03:08 PM
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NACA Duct vs Hood Scoop?

Hey guys I wanted to get an opinion on this. A friend of mine (smart guy, not just a dumb friend lol) was suggesting that instead of a Hood Scoop off of something like a WRX, I should use a NACA duct to cool my TMIC. Anybody got any reasons why I should go with one versus the other?

Car: TMIC off of a Turbo 2 fitted onto an FB with a Turbo 13b.
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Old 05-03-13, 04:11 PM
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http://en.wikipedia.org/wiki/NACA_duct
[NACA duct] generally cannot achieve the larger ram pressures and flow volumes of an external design...
External design will generally flow more volume through your IC. It's up to you however to figure out if that increase in flow is actually beneficial versus the loss in drag from an external scoop.
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Old 05-03-13, 04:52 PM
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It doesn't really allow too much flow, it's fine for cooling a driver or coolers in the back (specially if there is some negative pressure air on the other side of the cooler). Since the 2nd gen cooler doesn't really have any negative pressure on the back side of it, I wouldn't recommend it. There is a reason those TMIC are also called inter-heaters!
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Old 05-03-13, 04:55 PM
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The biggest advantage of a NACA duct is way less drag. As mentioned before it may not give you the flow you need at the speeds you go in an FC.
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Old 05-03-13, 07:15 PM
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I know it's about less drag, and I figured it was less overall flow. From what I've read, NACA's basically create a vacuum of more dense air so I was wondering if the higher density+less drag compensated enough for the lack of overall flow. I won't pretend to know vast amounts about drag coefficients and airflow numbers but I know a little about them.

Consensus is basically go for a scoop over a NACA though so far eh?
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Old 05-03-13, 11:26 PM
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Yes, or a front mount since there is plenty of room on a 1st gen! I have a bigger size front mount from and old project you can have if you want to pay for shipping.
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Old 05-05-13, 01:30 AM
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Originally Posted by abeomid View Post
Yes, or a front mount since there is plenty of room on a 1st gen! I have a bigger size front mount from and old project you can have if you want to pay for shipping.
Can you tell me how much shipping is to 98252 (Granite Falls, WA)?

Never been one to pass up a good opportunity if I can help it
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Old 05-05-13, 04:41 PM
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I'll measure it up and weigh and check in the next couple of days!
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Old 05-05-13, 05:30 PM
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Originally Posted by abeomid View Post
I'll measure it up and weigh and check in the next couple of days!

Thank you friend
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Old 05-06-13, 04:41 PM
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The other issue with NACA ducts is as soon as you create a boundary layer they dramatically reduce in efficiency. i.e. They must be kept impecibly clean, at the right speed (each is designed around a specific mouth, taper, width and length) and at the correct angle of attack in order to function as designed.
Not saying they won't work given incorrect speed, dirty, or sideways action. They just won't be as efficiently.
Unless you're pushing for a very high top speed or have a very low power (again pushing for high speeds) I don't think you'll have issue with a scoop.
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