I absolutely love the look of the sleek OEM hood, and I feel all of the aftermarket hoods take away from the smooth lines of the car.

I remember seeing this a while ago....
http://www.s2ki.com/forums/index.php...ic=324009&st=0

And it never crossed my mind again until recently. Since our engine compartment is a pretty sealed area with the hood closed, I was thinking just a few small vents like these over the turbo area would let out a good amount of heat escape after turning the car off to lessen heatsoak, and possibly* help pull air out from behind the IC while moving (the air has to exit somewhere).

So I know the whole goal of hood vents is to create a low pressure area above the vent to help pull air out of the engine bay, and I'm assuming above the OEM hood is a high pressure area. So I was thinking about leaving some material on the backside of the vent, and bending it down to create a "ramp" for air to exit the vents. I know it's kind of hard to visualize what I'm trying to describe, so I'll try to draw up a pic of what I'm saying.

Thoughts? Has this ever been attempted?

 

I've seen it somewhere on an FD. Can't remember where.

 

Those Hondas look kick *** cool. Now I'm going to have to get a spare hood and give it a shot. Please post if you decide to go ahead and do it.

 

panspeed hood is a good example, just of a lot bigger hole then what youre thinking, it uses the ramp effect, but i think it also puts the diverter bulge in front of it i believe.

kevin.

 

hmm. interesting.

 

David Hayes has a thread about this in the Interior/Exterior section. Check it out. Pretty cool IMO.

 

I'm reading through the S2k thread right now, and it seems that with just the holes in his hood, it has a significant pressure drop from under to over the hood, so without the ramping effect, air is drawn out instead of forced in. I do plan on taking on this task, and I'll test airflow with streamers attached to the vent area.

 

check out BoOsTin FD hood I believe his is a cut oem hood, although I could be wrong. I have also seen it on a silver FD awhile back. not sure I have seen one done just right, but I do like the idea of a more smooth hood without the ramp up to the vent.

 

Just saw BoOsTin FD's hood on NP. Looks DAMN good IMO. But I wonder how functional it is. I'm going to pm right now and I'll update with what he replies.

I'm going to take a look under my hood when I get home, to see which "panels" would look good cut out, and which would be most beneficial.

Hopefully someone with airflow dynamics experience will chime in.

 

It does. Underneath the car.
Yep. Type in "hood vents" into the search engine, and you'll pull up tons of threads with plenty of pics using that same principle.

 

I personally like how david hayes, as mentioned above, has modified his hood. Im just waiting to see how he likes the effects of cutting it as he did. This is looking more and more tempting as many aftermarket hoods are pure garbage fitment wise.

 

Since the position of the stock and SMIC's is angled for air to enter and exit it upwards, I would think that there would be a benefit if that air could exit through the hood. Same thing with the stock position of the radiator, since it is designed for air to enter through the front bumper and get directed upwards, wouldn't having a place for airflow to exit through the top would be a better flow route?

 

Both the SMIC and radiator are not specifically angled that way for the airflow to "exit upwards". The airflow is slowed down drastically as it makes its way past the cores, so whichever direction the exit is doesn't really matter much.

The pressure over the majority of the hood is not a high pressure area; most of it is actually a low pressure area, because the airflow has to speed up to travel over the curved lines of the hood, versus the airflow going underneath the car. This is why even just cutting a hole in the hood like the S2K guys allows airflow out of the engine bay.

That said, you create much more of a low pressure area over the actual vent by fashioning a cutaway vent that creates an open space below the airflow over the main surface, like most of the vented hoods you see.

 

That hood used to be available from BOMEX a while back.

http://www.bomex.jp/mazda/fd/index.html#fb

The faspac hood would have been a nice option.

http://www.pbase.com/rx7rage/image/926800

 

if you want to keep the lines of the stock but have some ventilation, take a look at the FEED hood. the vents in the back are hard to see even if you know they are there. i know shineAuto makes a grat copy.

http://sawayoshi04.hp.infoseek.co.jp.../image/404.jpg
http://sawayoshi04.hp.infoseek.co.jp.../image/403.jpg
http://sawayoshi04.hp.infoseek.co.jp.../image/303.jpg

 

Ahh I hate that hood!

I've always been interested in the idea of an OEM style vented hood. I'd really only like 1 cut-out, though. Something similar to the FEED headlight cover, but on the hood above the intake.

 

https://www.rx7club.com/interior-exterior-audio-26/fd-hood-vents-need-help-653405/

 

Hi boys,
I am probably going to be flamed with "already done" or this sounds stupid, but I'm going to throw it out there and see what the feedback is.
Why not remove the rubber seal at the windshield side of the hood?
While the car is in motion, the shape of the hood should create a "low pressure" area right behind its rear edge and "suck" the hot air out of the engine compartment...
Just my 2 cents.
It should also be possible to retain some of the seal and perhaps create some gaps to vent...
Go ahead and kill me...

 

iv heard about this...does it work?

 

i'm wondering these kind of vented hoods.... is our car gonna be risking it's life for exposing to rain water directly going into them ?

 

Already been done. and it sounds stupid! j/k...i did it on my 240sx, its pretty normal to see it on that car cause it creates such a big gap. i was wondering about my fd though. i'm sure it would create some sort of increased air flow.

 

I've cut big ugly holes in a spare hood, and done some brief testing involving "ramps" on the leading edge of the hole in an attempt to draw more hot air out at speed. A few wool-tufts taped to the inside tells me they work. For the initial test, I mocked up some triangular pieces by bending cardboard and taping it to the hood. Without the "ramps" the wool tufts were drawn into the engine bay, and with them installed the tufts were drawn inside as early as 30MPH.


I haven't taken any nice photos (because I haven't finished the project yet), but I'll try to post here when I'm completely done.


-s-

 

Here is pic of what i did to my hood.



Its bit more agressive than those in pic you posted, but works very well. Pic is taken with mobile phone so its bit messy, sorry

 

You're trying to do what I've been contemplating for awhile also. I've started a thread as listed above so how about posting any pics you have there so it will be easy to find in the future?

Current status of my hood:



I'm waiting for the mesh inserts to come back from powder coating. They're due in any day and then the hood will be done. I really like the mesh insert on the Honda S2000 - this will be a good fallback if my mesh doesn't look good.

 

There is a vent kit for the OEM hood from Fam Speed: http://www2u.biglobe.ne.jp/~fam/ (in Japanese sorry)

Scroll down http://www2u.biglobe.ne.jp/~fam/parts/fd/index.html and you will see the two red ducts.