Hood Scoop vs NACA Duct

[MrPhido]

I am contemplating putting an AFE Cold Air Intake on my 2004 Vibe. The AFE seems to be the most expensive, but it has a heat shield wit a top on it which creates a space which air could be ducted just over the top of the battery and into the intake to create a true COLD air intake. (See Step 15 of http://www.afefilters.com/is/51-10702.pdf) The first idea is to use two Aero Scoops (one outside to catch the high pressure air at the front edge of the hood and one inside to direct it , e.g. http://www.oocrcracing.com/how_it_works.htm (yes, I realize this is a model racing website). The second idea is an NACA duct cut in the hood which would catch the low pressure air over the hood and direct it as such. http://www.revlimiter.net/mods/duct.html (3rd picture down) Which do you think will work better, and why.

[djb383]

I would say try to make it ram air with the intake at the leading edge of the hood or in the higher air pressure area in front of the grille/bumper area. Any ram air system will always be a CAI. A CAI is not necessarily a ram air system. Keep us posted.

[manicdan]

i would get a intake you like and build the shield on your own, its not hard at all with sheets of aluminum and a saw blade for cutting soft metal. it can look unique and work very close to what the best can do. keep in mind the best options are designed by engineers for multi million dollar vehicles. so they have to be perfect, your car will never need such technology. but if u want to impress the one engineer that walks by your car and knows what hes looking at, then yeah go for it.

[satur9]

i have the afe intake. when your moving its exactly the same temp as my old k&n typhoon. and that was about 2-5 degrees above ambient. im not sure what cold airs are but they cant be that much cooler. when youre stopped intake air heats up quick. just slightly less quick than k&N. i think the best bet is instead of ducting to the intake is hood scoops or extractors to pull the underhood heat out. this would prevent heatsoak. ducting over the battery would work as long as it was sealed arond the battery which may be difficult.weapon-r dragon filter heat shield and ram air might be an cheaper easier way to go.i bought the afe cause it looks cool and i got tired of oiling my k&n

[WaveAction]

i like the NACA airduct, i was looking at this CF hood that had one exactly like that through a company i know of around my area. i'd like to see if you do this and the outcome