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hood vents: ideas...


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People don't seem to be able to look at the front intake area, measure it's area if necessary, and then ask - where does all this air that comes in the front go to? And then ask, where do I want it to go for aero and cooling purposes? And then work out the location and area of exit vents/areas to suit?

 

There is so much info on this topic here in this forum yet still there seems to be problems applying it to a particular car. You really have to think this thing through but basically it is simple if you are methodical.

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  • 1 month later...

Yes!!!! That is the go, if you are going to vent the engine bay then do it properly considering the amount of air that is involved. As far as cooling efficiency goes, with an aero advantage too, do it right and you will get a real advantage. Proven, not intrawebs 'look at me' ego rubbish.

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Has any testing been done on the effectiveness of the 280zx vents on the late turbo cars,which have the NACA style vent.

 

I'm thinking that if Nissan got it right on the 28they turbo (they usually do with theri development) it's just a question of grafting the vents on to an S30 hood. What's eveyones thoughts on this, i don't see it done that often which makes me wonder why as it's appears an obvious route. :huh:

Edited by 24OZ
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The S130 chassis has considerably different aero characteristics than the S30. They will not just "graft in" without some study and actually work, unless you just get really lucky.

 

I am considering taking the stock type 77-78 S30 hood vents, and moving them down on the hood so the leading edge of the "power bulge" lines up with the edges of the hood vents...such that you could draw a straight line across the fronts of them. The vents don't look great sitting there, but if they line up correctly and work then the less than stellar looks will be fine.

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  • 3 months later...

Posted this on C-C no response yet so I figured I would post here as well. I directed the curve of the vents to direct air passed the a-pillars and around the side of the car. I have yet to cut them as I am looking for input as mentioned below.

 

8177203694_6098647e73.jpg

Untitled by peej410, on Flickr

 

8177156285_9ba1cc627a.jpg

Untitled by peej410, on Flickr

 

Please ignore the random tape. I get excited at times haha.

 

I am looking to mimic this,

 

8177308749_773a697ec5.jpg

fordgt by peej410, on Flickr

 

8177299188_81def5a599.jpg

top_by_B3nzin by peej410, on Flickr

 

My radiator is already angled forward and can go far further without too much effort. The only real piece in the way is the upper radiator hose.

 

I did have a concern that the vents are not directly behind the radiator and fan

 

Also the intended vent area at its mouth is about half of the radiators inlet area. So 50% of the air coming in would be able to get out. Would this be a significant enough improvement in air management to consider all the effort?

__________________

Edited by peej410
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You don't need 100% of the rad opening to get the air out. The air flowing over the hood will help to suck it out. If you look at the Ford Focus rally cars of a couple years ago for example they have some very oddly shaped exaust tubes going to fairly small openings in the hood. The hood openings look kind of like the 70's Dodges with a 2" tall slit that is maybe 10 or 12" long.

 

I prefer 74_5.0L_Z's exhaust as it has a closed tunnel in and out of the car, that means that the air doesn't have to "find" the vent, but if you did this you would probably see a huge improvement over stock.

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  • 2 weeks later...

Alright so I took the plunge.

 

I currently cant drop the vents that far because the leading edge of the vent hits either the radiator inlet or the fan controller mounted to the shroud. To increase over all area I am going to leave the inner edge open and make the vent larger under the hood.

I will try to get both vents to merge at a point. I may ditch the ford taurus fan for a setup that is easier to duct to.

 

8200474863_714591d954.jpg

Untitled by peej410, on Flickr

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Thanks! I did have a new Idea to exploit the highest pressure area in the vehicle for the inlet of the rad. On the front of my car the aluminum strip between the splitter and the air dam is 2.5in tall I could make a 34in rectangular slot. It is the highest pressure area in the front end. I could completely block off the radiator, and duct the air up into the rad. Opinions?

Edited by peej410
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I was referring to the space between the air dam and the splitter. I wasnt going to remove the air dam just cut a slot in the vertical alu piece between the air dam and the splitter. Right now I dont have a cooling issue but if I take the car to Watkins Glen next season I would like it to be stable at 150+

 

 

8114912793_650c6408f1.jpg

DSC_0352 by peej410, on Flickr

 

Between the rivets essentially. Also The plan is to lower the car globally another inch but i need shorter front struts to do it.

Edited by peej410
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Based on this picture, I think you're going to have the same problem I'm going to have. At 130+MPH in my car it was rock stable. But at higher speeds I'm expecting to have to seriously reduce the height of the front end. I've actually bought a second pair of strut housings and plan to section them about 1.5-2 inches up front. I'd think you need the splitter at least within 2-2.5 inches of the road surface to get function use out of it.

 

I was referring to the space between the air dam and the splitter. I wasnt going to remove the air dam just cut a slot in the vertical alu piece between the air dam and the splitter. Right now I dont have a cooling issue but if I take the car to Watkins Glen next season I would like it to be stable at 150+

 

 

8114912793_650c6408f1.jpg

DSC_0352 by peej410, on Flickr

 

Between the rivets essentially. Also The plan is to lower the car globally another inch but i need shorter front struts to do it.

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I was referring to the space between the air dam and the splitter. I wasnt going to remove the air dam just cut a slot in the vertical alu piece between the air dam and the splitter. Right now I dont have a cooling issue but if I take the car to Watkins Glen next season I would like it to be stable at 150+

If you cut into the aluminum part then I think you'll reduce the pressure on the splitter by letting more of the air on top of the splitter divert to the radiator. I would think you would want a taller airdam if the goal was more downforce. If you have Competition Car Aerodynamics by McBeath, you can see how tall the high pressure area in front of a splitter can be on p.65.

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