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Hood Ventilation Ideas

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Old Aug 1, 2007 | 03:43 PM
  #26  
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From: A Pacific Island.
I think he's quoting me, but hasn't taken his meds yet....

S
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Old Aug 1, 2007 | 04:04 PM
  #27  
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Originally Posted by MazdaManiac
Lots of big ideas. Here is a little one that actually works:

Remove the rubber seal from the cowl.

You suck
But it's a good idea.

I'll try it.
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Old Aug 1, 2007 | 04:10 PM
  #28  
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From: Under my car
I did it on mine and ran around with a laser thermometer for a few days.
When you are stopped, the heat pours out from that opening - which is not nice if you use the "fresh air" option on your A/C controls (I never do because I like to recirculate the new-car smell!). Temps there can be up to 160°F.
When you are moving, it "splatters" at a frequency that I suspect is regulated by some resonant effect tied to speed. I saw oscillations from ambient (around 104°F) up to 140°F.
Most importantly, it moved up my "break-over" ambient temp up from 107°F or so.
I can rage along at that ambient temp now, whereas before, I'd start to overheat with the A/C on and over 4000 RPM.
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Old Aug 1, 2007 | 04:33 PM
  #29  
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if that space between the hood and wind shield is a escape route for hot air, than wouldn't cutting the triangle dip in the center of our hoods help more hot air get out of the engine bay?

I know the OP counted out cutting into the hood, and his idea sounds better/easier than mine. Although I would rather like too just control the height of the hood with a #'ed switch.
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Old Aug 1, 2007 | 04:38 PM
  #30  
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From: A Pacific Island.
When your are moving the back of the hood becomes a high pressure area, and air would move IN, exactly what you don't need.....

When standing still it would let hot air out, but cripple your a/c inlet, so it would be for hard core racers only. First prove your "hardness" by removing the a/c to save weight. Then the open-at-the-rear hood means something.

S
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Old Aug 1, 2007 | 04:39 PM
  #31  
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You could but the inside of this hood is a bit different then a standard hood on the inside because its aluminum.
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Old Aug 1, 2007 | 04:39 PM
  #32  
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yeah, I removed the rubber stripe from the back of my hood as well and I can see the heat waves poor out it now. And my oil temps are about 5-degrees cooler, and water temps about 6-7 degrees cooler at speed and around 3-4 degrees cooler while in traffic, confirmed with a sCANalyser.

It takes 2 seconds to pull off the stripe, and you can put it back quite easily if you want to. And it doesn't make anything look different.

Vents in the triangle is what the Veilside hood does.
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Old Aug 1, 2007 | 04:45 PM
  #33  
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Fabricate a vent that channels air through the little square holes in the frame (located just behind and above the tires) and out the fender vents. That will satisfy your desire for cooler engine temps, and ½ this board's desire to have functional fender vents
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Old Aug 1, 2007 | 06:53 PM
  #34  
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the optimal place for a vent is somewhere before or in the front of the triangle in the hood. Its where the flow seperates from the body (just wash your car and take it for a spin....) and can provide the best flow from the engine bay being in the area between the airbox/battery/ecu area and engine
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Old Aug 1, 2007 | 08:32 PM
  #35  
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From: Delray Beach, FL
I found a solution, and it works simply fantastic!
I even tried to switch back an forth to make sure the difference is there and I am not imagining things, and hell yes. It works great whether at high speed or stand still.
As MM suggested I removed the rubber stripe, and on top of it to increase the opening, glued in two plastick blocks about 3/4" tall, so whe the hood closes, the blocks push thecurve of it up a little, making the opening much larger.

That is it. Solved the problem of overheating right up. No more need for the 800 hood.
Costs $0.00 :-) and looks great.

I may post a coule of pics just to show where I had added the plastick pieces, if anyone really needs it.

Thanks everyone for your help.
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Old Aug 1, 2007 | 08:34 PM
  #36  
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Oh yeh, I don't care about drawing air from outside. Alwys recirculate. If I want outside air, I'll open the window.
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Old Aug 1, 2007 | 08:45 PM
  #37  
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From: Under my car
Yeah, I forgot to mention the adhesive foam "chocks" I put along the edge of the cowl plastic to keep the opening at maximum.
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Old Aug 1, 2007 | 09:06 PM
  #38  
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Originally Posted by StealthTL
When your are moving the back of the hood becomes a high pressure area, and air would move IN, exactly what you don't need.....
I'm guessing the aerodynamics of the car create a low pressure zone under the car so when you are moving and drawing air in your cowl is it moving over and past the engine then down under the car and out. It would also create downforce if that theory is true. Too bad its beyond the equiptment I have to test this theory. Anybody want to loan me a windtunnel?


Originally Posted by StealthTL
When standing still it would let hot air out, but cripple your a/c inlet, so it would be for hard core racers only. First prove your "hardness" by removing the a/c to save weight. Then the open-at-the-rear hood means something.

S
I think you wouldn't have to be a hardcore racer to appreciate more air cooling. I bet anyone that runs the oil temps upwards of the 260s would find this useful.
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Old Aug 1, 2007 | 09:44 PM
  #39  
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Originally Posted by mac11
I'm guessing the aerodynamics of the car create a low pressure zone under the car so when you are moving and drawing air in your cowl is it moving over and past the engine then down under the car and out...
Dude, I don't know about the down-force, but whatever it is it works like a charm.

Here in South FL the FL turnpike it is very common to see people do 100 MPH and more during the rush hour. when you are going 80, it just feels slow, and cars are catching on to you and begin to pass.
At this speeds, usually if I go into boost (which is happening instantly, as soon as I open the throttle), the coolant temps would get close to a 100C in a matter of seconds. So I had to be real careful not to overdo it.

Today I tried it with the new mode...
I just couldn't get it there.

I was trying really hard to get the engine to go hot.
only driving it in 2nd gear at 8K+ rpm and around -15 - 20 HG with AF around 15.3-15.7 for probably a minute or more it finally got hot.
(By the way, I fixed that, and added fuel to get the AF to 14 in that area )

And in Idles, it just doesn't get hot anymore.

Oh by the way, I would like to say a special thanks to MM.
If it wasn't for him, I would have probably dropped at least a 100 bucks getting the parts to get it to automatically open (if not more).
Yes it would have worked, and it would be a cool thing to watch your hood rise while you drive, but I don't care. All I wanted was to get it to run cooler, so thanks MM.
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Old Aug 1, 2007 | 10:16 PM
  #40  
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Originally Posted by rotorocks
Oh by the way, I would like to say a special thanks to MM.
If it wasn't for him, I would have probably dropped at least a 100 bucks getting the parts to get it to automatically open (if not more).
Yes it would have worked, and it would be a cool thing to watch your hood rise while you drive, but I don't care. All I wanted was to get it to run cooler, so thanks MM.
Glad it worked for you!
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Old Aug 2, 2007 | 03:56 AM
  #41  
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From: PCB
Can we get pics?
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Old Aug 2, 2007 | 05:30 AM
  #42  
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or you can do what I did to mine

still a work in progress and needs the holes cut out and painted etc



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Old Aug 2, 2007 | 06:20 AM
  #43  
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Originally Posted by MazdaManiac
Yeah, I forgot to mention the adhesive foam "chocks" I put along the edge of the cowl plastic to keep the opening at maximum.
A picture is worth a thousand words.
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Old Aug 2, 2007 | 06:55 AM
  #44  
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From: PA
Originally Posted by MazdaManiac
When you are moving, it "splatters" at a frequency that I suspect is regulated by some resonant effect tied to speed.

that would be a votex in a turbulent high pressure zone...

... which is also why the rain collects in the hood rotor symbol and dances around gently - there is no air movement

Last edited by r0tor; Aug 2, 2007 at 06:57 AM.
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Old Aug 2, 2007 | 07:29 AM
  #45  
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I disagree that there is no air movement.
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Old Aug 2, 2007 | 08:32 AM
  #46  
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Originally Posted by mac11
I disagree that there is no air movement.
good for you...

now look at what an average aerodynamic profile looks like and see the flow boundary leave the hood around the 1/3 of the way and learn the reason for that departure from the hood is a high pressure vortex at the cowl area...


and then look at a functional cowl induction hood and how it directs air from the cowl directly into the carberator... wouldn't make sense to put an intake in an area where air is drawing away now whould it?
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Old Aug 2, 2007 | 08:35 AM
  #47  
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That **** is not designed in the same way the RX-8 hood/cowl is. The center of the hood draws in very little/no air as compared to the outer edges. There is also plenty of airflow over the rotor shaped area and the "gutters" around the rotor.
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Old Aug 2, 2007 | 09:10 AM
  #48  
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I'd give a damn if it didn't work, and made things worse, but it works, whether by pulling cold air into the hood, or sucking hot air it out. Who cares? As long as it works and it keeps the engine cooler it is all that matter to me.
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Old Aug 2, 2007 | 09:12 AM
  #49  
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Amemiya make a $2-300 solution depending on carbon or fro. You can see from the bottom pic it vents out the back as well.

http://www.re-amemiya.co.jp/commodit...59858&scd=9295


Last edited by savedsol; Aug 2, 2007 at 09:16 AM.
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Old Aug 2, 2007 | 09:31 AM
  #50  
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Would work, but would require cutting.
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