New Hood Mod! NACA Ducts!

[SilverBullet75]

Thanks all!
Yes, eventually they will be plumbed into the airbox, but right now I'm out of budget $ and time.

As for the ebay question... no, these are 100% hand made. I started it by designing the shape on Adobe Illustrator. Then measured the insert for placement. Then, cut out the insert, cut the sheet metal hood below the insert, and used the cutout pieces as the "trays" for the ducts. From there, fiberglass and body filler went into play...
16 hours later...
They are done!
Only one thing I'm going to fix... I added a mesh screen. I don't like it though. It's used to cover up the bare sheet metal and hood structural supports. So, I'm going to cut the hood about 5 inches more toward the interior so that none of that will be seen, and I wont need a screen.

Oh... an for the request for pressures... Dude, I'm a jack-of-all-trades, but not a windtunnel expert! LOL I wish I could help with that info. It would be useful I'm sure.
Thanks!
---JIM---

[Ldub]

Just a thought re: mesh/ cutting more sheet metal/ hiding bare metal...

Flat Black Paint, Covers A Multitude of Sins.

[SilverBullet75]

LOL... believe me.. I've tried!

[Triathlete]

Hmmmm! Whats going to keep the water out on those rainy days?

[Ldub]

Hmmmm! Whats going to keep the water out on those rainy days?

I was thinking a chunk of sponge or high density foam cut to fit (HAS to be black, of course), would slow it down to a drip on those rainy days & keep out most of the cold air during the frigid winters we experience way up nort.

[thedutchguy]

Me think you brave man to take two days of !

[iamjacksadrenalgland]

actually, NACA ducts are designed to vent air out from under the hood. there's a pressure difference between air flowing over the hood and air trapped under the hood.

this issue was debated at great length on a porsche forum that i used to belong to when 944 owners considered using hoods set up with NACA ducts plumbed to their intakes.

... and now for today's automotive fun facts ...

in 1979 porsche decided to build a turbocharged version of their normally aspirated 924. in order to accomodate the extra heat generated, they fashioned an NACA duct directly over the exhaust manifold/turbocharger.

in 1981 porsche offered a limited production 924 carrera GT which utilized an intercooler between the turbocharger outlet and the intake manifold. the resulting temperature drop allowed for more boost and more power. in order to provide airflow over the top mounted intercooler, they fashioned a large scoop on the hood.

[Hotsauce]

I was thinking a chunk of sponge or high density foam cut to fit (HAS to be black, of course), would slow it down to a drip on those rainy days & keep out most of the cold air during the frigid winters we experience way up nort.

Cold air= power. Cold fresh air is good, but obviously too much water is bad. My truck makes noticably more power on really cold days.

I really don't think you can get up enough air pressure for any signifigant ram air effect, but the cold air will help.

John C.

[Ldub]

Cold air= power. Cold fresh air is good, but obviously too much water is bad. My truck makes noticably more power on really cold days.

I really don't think you can get up enough air pressure for any signifigant ram air effect, but the cold air will help.

John C.

I'm right there with ya John...to a point, that point being around zero, or a little above.
There's a reason older cars had heat risers ducting warm air from around the exhaust manifold up to the intake, same reason our throttle body is plumbed into the cooling system.
In severe cold, warming the intake (combustion) air a bit makes combustion happen more easily.
On mine, I've plumbed a bypass around the throttle body (using ball valves) that shuts off the coolant during the above freezing months.
My two cents.
SilverBullet, Sorry for the thread-jack.

[WormGod]

Looks good and clean. Killer work!

I would love to do a sort of Evo style insert mod to suck some heat out. Unfortunately, that would mean losing some stability in the hood from the cutting needed, but damn, would that look good.

[VCAMILO]

Awesome! The mod looks real nice... It never rains in AZ or in Nevada... LOL!