Has any one used NACA ducts on the body before? I want to add a single small NACA duct in each of the 1/4 pannels beind the door and infront of the fender (down low sorta) to aid in engine cooling (routed to the fan and ex-oil cooler).
Any tips on its mounting? any pictures?
Thanks!
Jonathan
NACA ducts (body mounting)
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miller
- Posts: 416
- Joined: Thu Nov 14, 2002 12:01 am
um I guess all I can say is mounts the thing perfectly flush. I sometimes see people just rivet em on so their is a lip on the side facing the airflow. I may be wrong but that might affect the airflow going into the naca duct a bit. Oh and where are you gonna mount it? From what ive read they dont work well unless they are direcly facing the airflow. Like if you cant see if from lookin straight at the car head on most likely they arent working to their fullest.
Does anybody else have info. Im pretty interested in naca ducts too.
Does anybody else have info. Im pretty interested in naca ducts too.
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Rosebob
- Posts: 75
- Joined: Wed Nov 26, 2003 5:39 pm
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Super VW.
I wanted to mount it under the window bettween the back of the door and front of the rear fender.
I have seen them riveted, looks to hack job that way i think.
They will be going to the fan intake, runing from the duct, over the hump (rear seat area) and through the firewall pointed at the fan intake.
I have decided not to use one for the external oil cooler, as it will have a fan of its own. so both ducts will go to the fan intake to help with head cooling.
does any one have pictures of NACA ducts on body pannels? not just in windowows.
Thanks!
Jonathan
I have seen them riveted, looks to hack job that way i think.
They will be going to the fan intake, runing from the duct, over the hump (rear seat area) and through the firewall pointed at the fan intake.
I have decided not to use one for the external oil cooler, as it will have a fan of its own. so both ducts will go to the fan intake to help with head cooling.
does any one have pictures of NACA ducts on body pannels? not just in windowows.
Thanks!
Jonathan
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Sharkey
- Posts: 966
- Joined: Sat Jul 22, 2000 12:01 am
If it was me and I was installing a single NACA duct near each rear quarter as you described, I'd run one to either the cooling fan area or an aircleaner box. The second I would run to the oil cooler. Just because you have an electric fan providing airflow through a remote oil cooler doesn't mean that your source of incoming air isn't cold.
Let's say you install a single NACA duct on the right side quarter panel, down low near the running board. This I would duct into the engine compartment like you described to provide additional airflow for your engine cooling fan and air cleaners. If you were running a single air cleaner (like in a turbo set-up), I'd duct the air solely to that. Let the vents under the rear window provide the cooling air for the fan inside the shroud.
Now let's install a second duct on the left side quarter panel to match the one on the other side. Use some HVAC ducting from your local Home Depot and build a shroud around your remote oil cooler. I did this last fall because without such a shroud, it is too easy to recirculate the air that has already gone through the cooler once. I then used some 4" ducting and connected it to a inlet duct mounted to the left rear torsion bar tube. Mine is totally hidden, but a NACA duct would probably work a little better.
This is pretty much the scenario I'm running. I have a turbo motor with a remote airbox fed by a duct near the right rear torsion bar tube. My remote oil cooler gets its air supply from a similar duct mounted on the left rear torsion bar tube. That leaves the vents below the rear window to concentrate on providing air for the just cooling fan inside my shroud.
And as for pics of NACA ducts, I should have one for you in about a week or so. My decklid is currently sitting at a body shop having the finishing touches peformed on my own NACA duct install (followed up by paint). I installed mine 50/50 as far as looks/functionality goes. Originally I was going to mount my air filter inside the engine compartment and this would necessitate extra airflow into this area. Even though I decided to go with a dedicated remote air filter air inlet location instead (for colder air), I'm keeping the duct.
Like I said, pictures to follow...
PS: NACA ducts do not have to be directly in the airflow like a conventional ram-air scoop (assuming that the geometrics are correct). A properly designed duct -- and there are formulae to determine their width, length, and depth -- can be installed on a surface that is 100% parallel to the airflow and it will funnel in a surprising amount of air.
PPS: I know of at least one ShopTalk Forum member with NACA ducts successfully installed...
http://www.shoptalkforums.com/profile.p ... ile&u=3636
Let's say you install a single NACA duct on the right side quarter panel, down low near the running board. This I would duct into the engine compartment like you described to provide additional airflow for your engine cooling fan and air cleaners. If you were running a single air cleaner (like in a turbo set-up), I'd duct the air solely to that. Let the vents under the rear window provide the cooling air for the fan inside the shroud.
Now let's install a second duct on the left side quarter panel to match the one on the other side. Use some HVAC ducting from your local Home Depot and build a shroud around your remote oil cooler. I did this last fall because without such a shroud, it is too easy to recirculate the air that has already gone through the cooler once. I then used some 4" ducting and connected it to a inlet duct mounted to the left rear torsion bar tube. Mine is totally hidden, but a NACA duct would probably work a little better.
This is pretty much the scenario I'm running. I have a turbo motor with a remote airbox fed by a duct near the right rear torsion bar tube. My remote oil cooler gets its air supply from a similar duct mounted on the left rear torsion bar tube. That leaves the vents below the rear window to concentrate on providing air for the just cooling fan inside my shroud.
And as for pics of NACA ducts, I should have one for you in about a week or so. My decklid is currently sitting at a body shop having the finishing touches peformed on my own NACA duct install (followed up by paint). I installed mine 50/50 as far as looks/functionality goes. Originally I was going to mount my air filter inside the engine compartment and this would necessitate extra airflow into this area. Even though I decided to go with a dedicated remote air filter air inlet location instead (for colder air), I'm keeping the duct.
Like I said, pictures to follow...
PS: NACA ducts do not have to be directly in the airflow like a conventional ram-air scoop (assuming that the geometrics are correct). A properly designed duct -- and there are formulae to determine their width, length, and depth -- can be installed on a surface that is 100% parallel to the airflow and it will funnel in a surprising amount of air.
PPS: I know of at least one ShopTalk Forum member with NACA ducts successfully installed...
http://www.shoptalkforums.com/profile.p ... ile&u=3636
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Plasticfantastic
- Posts: 763
- Joined: Sun Jun 10, 2001 12:01 am
. I used stainless button heads.
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miller
- Posts: 416
- Joined: Thu Nov 14, 2002 12:01 am
Wasent baggin on you panel. Your bus is lookin sweet by the way.
Ok I just skimmed over Tune To Win by caroll smith. Has a great section on NACA ducts. Here are some general tidbits.
1. They should be mounted in an area that has a shallow boundry area. Basically the boundry area is the invisible boundry where there is low pressure are over your car. Like your front bumper would have almost no boundary area but your rear window would have a fairly large one. If you know what im talkin about then it shouldnt be to hard to visualise good spots to mount the ducts. Something to remember is the boundary area tends to get thicker the further back on the vehicle you go.
2. The duct must be aligned parallel to the local airflow. So panels naca ducts would be a good place for them givin this general rule.
3. This is probably the most important but overlooked aspect about ducts. When the air comes in it NEEDS somewhere to go. Its not just gonna conviently go away after it cools what needs cooling. A great way to mount a naca duct is to have the oil cooler/intercooler/radiator whatever right behind the nace duct and then have a drain duct behind the oil cooler to let the air escape. Eh its kind of hard to explain. let me see if I can come up with a pic.
--------------NACA inle -----NACA outlet ----------------------
-- 88 --
-- 88 --
---------------------
The 88 is the oil cooler. Hope that can clarify what I mean.
88 --
Ok I just skimmed over Tune To Win by caroll smith. Has a great section on NACA ducts. Here are some general tidbits.
1. They should be mounted in an area that has a shallow boundry area. Basically the boundry area is the invisible boundry where there is low pressure are over your car. Like your front bumper would have almost no boundary area but your rear window would have a fairly large one. If you know what im talkin about then it shouldnt be to hard to visualise good spots to mount the ducts. Something to remember is the boundary area tends to get thicker the further back on the vehicle you go.
2. The duct must be aligned parallel to the local airflow. So panels naca ducts would be a good place for them givin this general rule.
3. This is probably the most important but overlooked aspect about ducts. When the air comes in it NEEDS somewhere to go. Its not just gonna conviently go away after it cools what needs cooling. A great way to mount a naca duct is to have the oil cooler/intercooler/radiator whatever right behind the nace duct and then have a drain duct behind the oil cooler to let the air escape. Eh its kind of hard to explain. let me see if I can come up with a pic.
--------------NACA inle -----NACA outlet ----------------------
-- 88 --
-- 88 --
---------------------
The 88 is the oil cooler. Hope that can clarify what I mean.
88 --
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Plasticfantastic
- Posts: 763
- Joined: Sun Jun 10, 2001 12:01 am
I know Miller, I was just joking around 
. With all the crazy mods I've done to my bus, the last thing I could be is too sensitive about critizism...
When I put mine in, they were 99% for looks. I was gonna run a big type IV and use them to give it just a little extra air...but then came the Eco idea and the addition of a radiator. It is very good to hear that they might actually catch some decent air, the whole rad placement/ducting thing is a gamble right now, I don't know if it will cool enough.
. With all the crazy mods I've done to my bus, the last thing I could be is too sensitive about critizism...When I put mine in, they were 99% for looks. I was gonna run a big type IV and use them to give it just a little extra air...but then came the Eco idea and the addition of a radiator. It is very good to hear that they might actually catch some decent air, the whole rad placement/ducting thing is a gamble right now, I don't know if it will cool enough.
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super vw.
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Plasticfantastic
- Posts: 763
- Joined: Sun Jun 10, 2001 12:01 am
Thanks Jonathan!
I made a large square matboard template (large and square because it was easier to make sure I was centered and perfectly vertical/horizontal) and taped that on the bus. Then I used a small air reciprocating saw with a fine tooth blade to do the hacking. The template kept the saw from scratching the paint as it bounced around the pattern. If you don't have a compressor, an electric jig saw would do fine. Either way, go slow and don't try to turn it too sharp.
Make sure you know exactly what is behind the area you are cutting on...
I made a large square matboard template (large and square because it was easier to make sure I was centered and perfectly vertical/horizontal) and taped that on the bus. Then I used a small air reciprocating saw with a fine tooth blade to do the hacking. The template kept the saw from scratching the paint as it bounced around the pattern. If you don't have a compressor, an electric jig saw would do fine. Either way, go slow and don't try to turn it too sharp.
Make sure you know exactly what is behind the area you are cutting on...
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Plasticfantastic
- Posts: 763
- Joined: Sun Jun 10, 2001 12:01 am
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super vw.
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Plasticfantastic
- Posts: 763
- Joined: Sun Jun 10, 2001 12:01 am
I lightly sanded/rounded the edge being careful not to chip the paint (which I did anyway in a couple of small places 
) and then used some gloss black enamel and a small model brush to paint the edge. My NACAs were the clear kind, I painted the backside of them gloss black too so the black edge to the opening helps the ducts to blend more
) and then used some gloss black enamel and a small model brush to paint the edge. My NACAs were the clear kind, I painted the backside of them gloss black too so the black edge to the opening helps the ducts to blend more