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Anyone using a LARGE NACA duct air intake?

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Old Feb 5, 2008 | 07:39 AM
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Lightbulb Anyone using a LARGE NACA duct air intake?

I'm thinking of dumping cool air into the intake via a NACA duct installed directily over a Pettit TKT Cool Air Intake kit, just inboard of the passenger-side headlight cover... If anyone has been down this road, please advise... Thanks!
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Old Feb 5, 2008 | 08:37 AM
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Possible, but would probably look goofy. BTW, I assume this is a race-only car - that would be a recipe for shoveling water into the intake on a street car.

Dale
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Old Feb 5, 2008 | 08:58 AM
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If you are "really" serious about this, there is a better way to go about it. Re-Amemiya has a headlight kit which has a duct built in. It's a sleek kit which removes the inside light to provide a fresh air duct. This would be a better option.
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Old Feb 5, 2008 | 10:22 AM
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WEll, it may sound silly, but I have been thinking about this for years. Maybe I'll sell you guys my kit when I get lots of cool air to the intake filters...
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Old Feb 5, 2008 | 11:08 AM
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I have a thread postulating the exact same thing, i'll find it and then edit this.

EDIT: found it here.

Since then i've seen one single turbo FD with an intake in the front bumper (and *no* intercooler) who claims to get lower IAT's than some people running large SMICS with little to no heat soak.

Last edited by NissanConvert; Feb 5, 2008 at 11:16 AM.
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Old Feb 5, 2008 | 11:22 AM
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Originally Posted by NissanConvert
Since then i've seen one single turbo FD with an intake in the front bumper (and *no* intercooler) who claims to get lower IAT's than some people running large SMICS with little to no heat soak.
I'd be impressed if the owner is NOT running some type of auxiliary injection.
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Old Feb 5, 2008 | 01:40 PM
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Originally Posted by Mahjik
I'd be impressed if the owner is NOT running some type of auxiliary injection.
I'm sure it's on the same page as one of my posts. I'm pretty sure it's been in the past month. I'll look for it real quick like.
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Old Feb 5, 2008 | 03:11 PM
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NACA ducts look so cool. Especially on cars like the F40... I don't know if they go with the FD as well. I agree with Mahjik who said to go with the RE headlight duct.
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Old Feb 6, 2008 | 11:11 AM
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I'm just concerned with how much air the RE headlight kit can provide. An RX-7 at full-throttle is a thirsty demon, and the RE intake hole looks to be about 3" wide...
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Old Feb 6, 2008 | 11:19 AM
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Isn't that the same size as the intake piping? Perfect!
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Old Feb 6, 2008 | 11:23 AM
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Originally Posted by Rebel-E
WEll, it may sound silly, but I have been thinking about this for years. Maybe I'll sell you guys my kit when I get lots of cool air to the intake filters...
I've been trying to do a CF naca duct on the stock HD for a while now. My goal was to paint the housing and leave the duct with the carbon exposed.

This is what you are refering to correct?
http://cgi.ebay.co.uk/NACA-DUCT-Stre...QQcmdZViewItem
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Old Feb 7, 2008 | 10:42 AM
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Originally Posted by Natey
Isn't that the same size as the intake piping? Perfect!
And that will increase air flow how, exactly?
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Old Feb 7, 2008 | 11:21 AM
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Originally Posted by Rebel-E
And that will increase air flow how, exactly?
What makes you think bringing in "more" air is going to help? The engine can only ingest so much. Also, the larger the scoop, the more resistance it creates. This is one of the many reasons why professional race teams use the smallest opening which gives them the amount of air they require (for intake, radiator and brake cooling).
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Old Feb 7, 2008 | 11:42 AM
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Originally Posted by Rebel-E
And that will increase air flow how, exactly?
No, but please tell me how any duct will increase airflow past two turbos and an intercooler.
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Old Feb 7, 2008 | 01:00 PM
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Originally Posted by Mahjik
I'd be impressed if the owner is NOT running some type of auxiliary injection.
I would be too, as he would be the first to have found a loophole in the laws of thermodynamics.
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Old Feb 7, 2008 | 01:22 PM
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it's cozmo kraemer. He's using water injection.

EDIT:
Originally Posted by Natey
No, but please tell me how any duct will increase airflow past two turbos and an intercooler.
A denser intake charge pre-turbo usually results in a denser intake charge at the throttle body. However -as it was commented in my thread on the subject- it probably won't show any appreciable gains unless you're trying to squeeze those last few HP out of a single turbo.
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Old Feb 7, 2008 | 01:46 PM
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Originally Posted by NissanConvert
it's cozmo kraemer. He's using water injection.
Now I believe it Chemical intercooling, FTW
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Old Feb 7, 2008 | 01:58 PM
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Originally Posted by Marshall
Now I believe it Chemical intercooling, FTW
He also notes in that thread that at stock boost levels (10psi) he sees 50c w/o water.
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Old Feb 7, 2008 | 02:06 PM
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Originally Posted by NissanConvert
He also notes in that thread that at stock boost levels (10psi) he sees 50c w/o water.
Absolutely. You can pick a large sized turbo and run it much under its effective power to generate low charge temps. However, I would be curious to see his charge temps after a 30 minutes session on a road course.
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Old Feb 8, 2008 | 11:14 AM
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Sorry, when I used the generic term "air", I didn't realize I was talking to an Engineering team... As far as I understand airflow, you can never increase flow above what the restriction point flows,while remaining normally aspirated (upstream of the turbos). My concern with the RE intake, is what are the flow characteristics of the piece? What if it is the new restriction point? And the point of the NACA hood (which is very aerodynamic, by the way) is to bring in outside, cooler air, versus hot underhood air temps. Cooler air equals more dense air, equals more horsepower. Better?
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Old Feb 8, 2008 | 01:32 PM
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Originally Posted by Rebel-E
Sorry, when I used the generic term "air", I didn't realize I was talking to an Engineering team... As far as I understand airflow, you can never increase flow above what the restriction point flows,while remaining normally aspirated (upstream of the turbos). My concern with the RE intake, is what are the flow characteristics of the piece? What if it is the new restriction point? And the point of the NACA hood (which is very aerodynamic, by the way) is to bring in outside, cooler air, versus hot underhood air temps. Cooler air equals more dense air, equals more horsepower. Better?
Any honda *** can put a duct in a hood and claim it makes horsepower. Here, you will get flamed for making such assertions without some sort of background.

We're aware of the aerodynamic qualities of NACA ducts.

I'm guessing (based on some fast and loose math i've generated from intercooler sprayer tests that i've seen in mags) that you're looking at maybe a 10hp increase. For the money you spend it won't be worth it as far as performance per $ goes. However if you love the way it looks on the car i suppose you may see it differently.

Test it, log it, videotape it, and then amaze us all.
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Old Feb 8, 2008 | 02:57 PM
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Originally Posted by NissanConvert
He also notes in that thread that at stock boost levels (10psi) he sees 50c w/o water.

must have been awful cold outside
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Old Feb 8, 2008 | 04:02 PM
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Originally Posted by Mahjik
If you are "really" serious about this, there is a better way to go about it. Re-Amemiya has a headlight kit which has a duct built in. It's a sleek kit which removes the inside light to provide a fresh air duct. This would be a better option.
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Old Feb 9, 2008 | 08:31 AM
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I've had this idea for years, cutting a hole in the hood in the triangle further back of the airbox adjacent to the airpump to fit a scoop that sits a top a fabbed airbox. the hood would close over the scoop and box such that the scoop goes through the hood. The location should accommodate single and twin turbo intakes and the scoop should peer high enough out of the hood to not collect water.

I think one should be able to find a box in a junk yard by sizing a rectangular panel filter to the make of a car. the box would be longer than the hole so the hood would hold down the scoop and box.

However I haven't had much success finding a scoop to fasten to the air box. I checked go carts thinking they may have something, and the ones the dragsters use are like two feet long. the most suitable shape I've found is the shell of a sideview mirror, though that would take some skill to fabricate so that it would look good.

So why would I want to do this? I don't think it's a good idea to launch with 70*C air. I've owned the car long enough that I would risk compromising looks for the benefit of cold air.

My other idea was to remove the ABS and put a duct thru the fender much like many diesel vehicles are doing for intakes. Though that would take more fabing of the turbo piping.

What's keeping me from doing this? Time. Encouragement. Talent. and knowledge of whether the final product would achieve the desired results.

I would do the work up on a damaged hood. any graphic artist out there?
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Old Feb 10, 2008 | 08:15 AM
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i'll post pics of mine later........I think its very effective.



you can see it abiut from my signature......ill get better pics later
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