Custom Hood Vents - APR NACA Ducts?
 

So I'm considering installing these NACA ducts in my hood.
http://www.mosaicmotorsports.com/ima...ucts_type2.jpg

In this area.
https://imageshack.com/a/img10/7604/b9i9.jpg

Then shim the hood a little bit maybe 1/4".
Then remove this plastic under the hood.
https://imageshack.com/a/img845/7977/9xwg.jpg

This should allow air to flow in and out. Might even cool the engine? What cha thinks?
Fuk buying a CF hood.

https://my350z.com/forum/autocross-r...tock-hood.html

Chebosto did something similar back in 07. Lots of Jeep/off road guys do this by installing hood vents off other make/models.

I'm doing something and prefer the OEM hood as well.

What do you want it to do? Why would you remove the plastic covers?

Hood spacers/shims make your hood look like the sh!t don't fit. I don't care if it works or not, if it's on a track car fine but for the street it just makes a car look busted.

Body work/fitment/paint has to be perfect to pull it off.

The shims and removing the plastic is just to make some room for the air to flow thru.
I agree if a hood is shimmed too much it looks dumb. I plan on using a couple thick washers.

This is solely my opinion but you can open your hood up and allow air in but air will not flow through your engine bay unless you give it a place to go…

if you do this mod consider where you want the air to flow and do your best to clear a route…

I personally think it looks tacky but that just my opinion...

Exactly. Normally you open up that area to allow air to flow out so your eng bay is cooler.

What exact location will you place the ducts?
What size are the ducts?Too small will look out of proportion.
Are you doing this soley for performance or,looks?
I agree that the OEM hood is pretty boring.I did Aston type vents
on my car.They are made out of finned aluminum billet.I slotted
the valleys.They do look good.However,the amount of air from
the ducting I did to the engine is probably not worth the effort.
I did mine mostly for design purposes.

The point of this is not for looks, and I know its borderline tacky thats why I want to discuss it before I do anything.

I want the air to flow in the vents, over top the engine bay (generally), and out the back of the hood which I've raised a bit with a few washers.
Removing the plastic and rubber trim will make room for the air to flow out.
I figure the air has a way in and out, in the same direction.

Size
http://images10.newegg.com/NeweggIma...xKqjhO76wI.jpg

Here's my car, it's clean. Function might cost a little bit.
A unpainted CF hood would prob look worse.
https://imageshack.com/a/img689/4689/imageaho.jpg

I'm not throwing stones at ya, don't take any offense to what I say, in fact, take it with a grain of salt.

It my opinion that you're airflow gains may be achievable, but the cost and trouble you'll go through to get 60 cfm of airflow at 75mph will be a big pain in the ass, disproportional cost, and will ultimately take 'value' away from the car.

and I believe that if car needed more airflow to vent engine temps than nissan would have designed the car with some sort of hood vents.

Great looking Z btw…and if you choose to do this and it completely looks like ass you can find another red hood and be back at square one...

Ya it's cool man, just a discussion. I figure it will cost $200. Car is paid for, I'll be buried in it. Lol
The 350z wasnt designed to be as sporty as it could be potentially. It has a heat problem, most people know that.
My car looks stock, but it has almost all the n/a mods it can have. Stock motor.
I added a oil cooler this year also. (Setrab)
A NACA duct doesnt draw in air like a scoop it "steals" air on the boundry layer also.
I'm looking around on google for more on this too.

These vents will help to keep the engine bay a little cooler at lowet speeds. This will work due to convection as hot air will try to rise up and possibly move out of the vents. At higher speeds, the air will need an escape route.

The paint/finish on these vents will decide the looks. If you can match it with the finish on B-pillars or match paint with the hood itself, it will look good.

Do post pics if you install it.

I think that NACA duct would look sweet. It did on my old Miata. I had one on the driver side installed on my stock hood.

But the flat area of the hood is generally low pressure and will not intake are very well. And the cowl area is generally a high pressure area that will not extract air very well.

True, because they knew the GTR was coming and if they wringed out the full 450whp the VQ is capable of the debut GTR would need 500+...

Cool man - well, if you do pull the trigger, make a dedicated thread - I'd love to see how it turns out…awesome that you have the car paid off, opens up alot of options. Give 'em hell!

I had wanted to do this but with different vents like the ucas ones off zil via

Attachment 435475
Not so good on a Honda.
https://img191.imageshack.us/img191/6821/sta72426.jpg
https://img191.imageshack.us/img191/9090/sta72427.jpg
Not bad on the G.
http://www.the370z.com/members/simot...raphic-008.jpg
Not bad on the 370.

wanna see this on an HR hood

Ya I actually found a lot of info on the Miata forums, via google. And the A/C Cobra forum.
I'm doubting air will flow in and out as easily as I thought. But if it makes an improvement then it would still be worth it to me.

I'm in the hvac trade, I have a thermometer that I can run a wire into the engine bay and take readings with. I'm going to start by getting readings back and forth from work. Then maybe remove the plastic I mentioned and shim the hood. If I get some drafting action it may draw some heat out of the engine bay.
Thats how convectional gas appliances work. The cooler outside air draws the hot vent gas up the c-vent and out the roof or chimney.
The cowl area is a high pressure area but the air is still going somewhere so it would have to take some heat with it in my opinion.

Thanks for the pics Sparco. I guess you can buy a CF hood with GTR style naca ducts. VIS sells it I think. It looks good on that red 370 for sure. His might be custom....
This is the VIS 350z GTR hood.
http://www.body-kitz.com/contents/me...2dr35-010c.jpg

Seibon for the 370z.
http://www.carbon-fiber-hoods.com/co...ood%5b1%5d.jpg
http://www.the370z.com/members/jjade...n-gtr-hood.jpg
http://www.carbonfiberhoods.com/blog...ema-2010-8.jpg

Instead of shimming the hood you could try removing the rear weather/rubber strip to let the air escape.

I've been thinking about this. It could be one of the most effective/cheapest mod ever..

I've taken the plastics (and the wiper assembly) toward the back of the engine bay out before and, IIRC, that actually gives you quite a bit of opening between the hood and the engine bay. It can look a little unsightly if you look straight down and depending on what you have there (I have some wiring there), you may not want that area directly exposed to the elements.

I just want to remove the rubber seals for the hood and the battery/brake mc covers.

I haven't seen flow characteristics for the Z but the cowl near the windshield is typically a high pressure zone. Which means you'll be pulling air into the hood from there actually slowing air flow through the radiator, creating more heat build up. Which is why they seal off that cowl area, along with a few other reasons. If the Z is different I'd like to see some data or studies. The air coming into the engine bay typically will flow down over the headers and under the car, which isn't ideal either but more practical for a street car than cutting holes in the hood/fenders.

This is correct.

Removing the rear weatherstrip will have the air coming in the grille fighting the air coming in from the back of the hood.

Anyone Remember Cowl induction hoods? They used the high pressure zone to direct air coming INTO the engine bay into the intake.

So shims, removing weather stripping, etc =:facepalm:

Nice, ya all I've done is removed the weather strip and the battery/braker master etc covers. They go back on in literally a min.
I do remember cowl induction hoods and the air is being INDUCED by the engine drawing the air in on a carburated motor. They didnt work by air being forced in, but by the engine pulling in from the low pressure zone right below where the air hits the windshield.

The space Ive created by removing those couple things IMO will allow some heat out with convection.

I'll end up buying a cf vented hood but I'll be painting it. But low priority, i'd rather get a Koyo rad.

Hmm
 

Not a fan of how those vents look, but for discussion's sake, what if those were installed the other direction (points towards the window)? Would it improve flow from the grill through the radiator and out the hood?

The Cowl area is a high pressure zone, meaning the air is going to just push its way in if theres room for it.. A lot of cars on ITBs do the shimmed hood thing to allow air to come into the ITBs.

Not only will this disrupt aerodynamics of the car (air should flow over it, not over the hood, into the engine bay [causing turbulence at that location] and then over the car.), But It really has no benefits for the Z.At idle, yes, it will allow for some heat to escape through there, but in motion?Na.

IMO the shimmed hood is more of a style thing.


If you are looking at maximing cooling, pre radiator is where you want some scoops...Attachment 435480

They ARE pointed towards the window....?

This design should aid in allowing air thats been heated up by the radiator (and the engine, and the exhaust manifold lol) to escape.

OP wants the points towards the nose so air "rams" in. I was asking about tips towards the windshield so air escapes out like those louvres in the pic I posted.

The design you posted would be very effective in dissipating heat.