Ram Air / Hood Cut Outs

[Dahoopd]

Would cutting holes in the hood above the SC top so that air flows under the hood help or would that cause turbulance. Im not talking about a major hole. Just something to force cool air over the motor.

[The_Ghost]

would you put like a scoop over it or something or just leave a hole? how big are we talking, and facing forwards or rearwards?

you could have an inlet a few inches before the top with a duct to point it downwards, but then that air has to go somewhere or else you will generate lift at higher speeds, or worse yet, smash your windshield and cause an accident.

so then, you could put an outlet duct just after the top. but that'd look stupid, it'd look like an =.

if you're interested in running cooler swap out your t-stat and set your hi-speed fan to run whenever the car is on. i did this using a relay switched into my auto on-off headlights. Since my sensor is hidden by the dash cover, my headlights are constantly on, so it doesnt matter. I usually operate on the far left edge of the "NORMAL" bracket, close to the C, and never get any hotter, even in hot, heavy stop-n-go 405 fwy traffic. seems to run stronger, too. I also deleted my ac condenser since my AC doesnt even work.

-ghost

[Dahoopd]

An open hole facing forwards with maybe mesh or something to keep birds/leaves from being sucked in. Was just an idea. I am going to sell my Cobra R hood and have an idea for a differant look.

[The_Ghost]

I think 03-04 cobra / 01 cobra heat extractor hood reverse vents would be fricken cool.

we have the 99 cobra hood on our 00 stang with the roush s3 kit, looks fricken shweet. you could get away with it on a mn12, too, probably, but I imagine that would probably be a fair amount of work.

I was thinking a 300ZX (Z31) turbo hood turboscoop might work okay mounted just slightly forward of where the top lives.

oh, and definitely use the mesh. though i like fried chicken, i would not like to find some roasted sparrow under my bonnet.

[Dahoopd]

So the air going into the engine bay isnt going to create a problem? Turbulance?

[darkstar_one]

hey dahoop!

check out mannys hood! its raised and has the scoops to extract the air out. I was thinking of buying some heat extractors from summit and having my neighbor modify them to my hood. I know it would work because the air going through the rad gets hot. and hot air rises. therfore the hot air at the top of the engine bay would be forced out by the cold air being pushed through the rad. and out throguh the heat extractors.

i was going to do it. but need to get a better hood that the one i have right now. it will come along.

its better if you go with the heat extractor idea. basically a scoop faced the wrong directions. facing the back.

[T-bird Tim]

For the trouble of cutting up your hood, adding the scoops and repainting; you may as well buy the Cervini cowl hood. It's lighter than stock, looks great and will help extract the hot air from beneath the hood.

[ThunderDave]

When I had my 91 with the turbo scoops I had put in the hood, one of them was right over the upper ic tube and it did keep it cooler to the point you could put your hand on it and leave it while it was running. How much that helped the intake temp I don't know.

[Dahoopd]

When I had my 91 with the turbo scoops I had put in the hood, one of them was right over the upper ic tube and it did keep it cooler to the point you could put your hand on it and leave it while it was running. How much that helped the intake temp I don't know.


Was there a way for the air to exit or did it just flow into the hood. I am assuming after Darkstars's explanation. The air needs to be sucked out for it to be beneficial. Just for example of what I was considering: The newer mustang hood scoop but with the center removed for air to go into the engine compartment. Not necessarily the same scoop but just to give you an idea. Front facing and open. I didnt think about the exiting portion of it.

[XR7 Dave]

Don't be a ricer. Don't add scoops unless you know what they will do. Just because you put a vent or scoop on your hood doesn't make it functional or effective.

Don't take it from me, do a little research on what the airflow pathways are over and around a car and also on the effect of airspeed and airpressure. You will spend less time learning about airflow than you will spend ruining the aerodynamics of your car/hood.

FWIW, to get you started, a cowl induction does not extract air from your engine compartment, conversely it is used to draw air into a carburator that is ducted to the reverse scoop. However, most cowl induction hoods are not designed so as to perform any function at all.

[Toms-SC]

Don't be a ricer. Don't add scoops unless you know what they will do. Just because you put a vent or scoop on your hood doesn't make it functional or effective.

Don't take it from me, do a little research on what the airflow pathways are over and around a car and also on the effect of airspeed and airpressure. You will spend less time learning about airflow than you will spend ruining the aerodynamics of your car/hood.

FWIW, to get you started, a cowl induction does not extract air from your engine compartment, conversely it is used to draw air into a carburator that is ducted to the reverse scoop. However, most cowl induction hoods are not designed so as to perform any function at all.

Just quoting again to make sure you all read it.

[Dahoopd]

FWIW, to get you started, a cowl induction does not extract air from your engine compartment, conversely it is used to draw air into a carburator that is ducted to the reverse scoop. However, most cowl induction hoods are not designed so as to perform any function at all.


Thanks Dave, I pretty much knew that but wasnt sure about a front facing scoop like in the pic attached. I was thinking of opening up the front of it. But I got the point. I bought a cobra R hood and I like the sleaker look of a factory hood with small scoop. I wont be running the salt flats any time soon so aerodynamics will only effect my gas mileage and that never bothered me. I will just leave it closed.

(sorry for the pic theft)

[mannysc]

Don't be a ricer. Don't add scoops unless you know what they will do. Just because you put a vent or scoop on your hood doesn't make it functional or effective.

Don't take it from me, do a little research on what the airflow pathways are over and around a car and also on the effect of airspeed and airpressure. You will spend less time learning about airflow than you will spend ruining the aerodynamics of your car/hood.

FWIW, to get you started, a cowl induction does not extract air from your engine compartment, conversely it is used to draw air into a carburator that is ducted to the reverse scoop. However, most cowl induction hoods are not designed so as to perform any function at all.

oooooooooooooooooohhhhhhhhhhhh! no you did not just go there ,

you callin me a ricer???

my scoops perform a function first off the two scoops run cold air into my air box via ducting and foam seals much like a ram air hood of the old days.

the back is open so hot under hood air is sucked out my windshield is proof .

its coated in blower oil after the front seal went out .

my under hood temps went down my engine temps went down all that hot air from radiator and ic unit have to go somewhere .

ive seen major lowering of temps in both air and water due to the scoops .

the original idea was to clear my inverted setup.

but ricer sheesh dave your hood has simulated scoops. ricers use fake scoops and such oops might you be a ricer too???


lol just kidding i thought they were ricey too. but what the heck im a californian and we low ride and rice our cars .

[Jeremy_K]

I regret putting the holes in my stock hood for the turbo coupe hood scoops. I will eventually pony up the cash to buy the cougar version of the cervinis hood. If you're looking to lower underhood temps, I would begin with losing that fiberglass mat from the bottom of the hood. That thing probably retains a lot of heat. Cooling the SC top is kinda useless since the air coming out of the blower is moving too fast to be cooled at that point.

[Dahoopd]

Well I got it from the functionality point but if someone thinks that scoop on the pic I attached looks like rice. Well thats just taste and Im only concerned about my own. Thanks for the input. I will leave it closed

[XR7 Dave]

No, the picture posted doesn't look like rice. FWIW I don't like the scoops in my hood either but before I go changing things I first take into account what effect it may have on airflow through my engine bay and around the car. If you put something on the car that adds to it cosmetically then great, but don't put scoops and vents all over the place thinking it will do this or that. That's what I meant by "ricer". If you want to create a positive effect by adding vents or scoops you first have to understand how air gets into and out of the engine bay of an SC.

That's all I was saying.

[David Neibert]

Keep in mind that forcing air underneath the hood by adding scoops, may cause the air pressure under the hood to increase to a point where less air will flow thru your radiator and IC. If the air is being forced directly to your air box...that wouldn't be a problem.

I think air flow across the radiator, IC core and the motor itself could be improved more by adding vents to exhaust the hot air quicker and reduce under hood air pressure, than by adding scoops and increasing under hood pressure.

David

[Dahoopd]

Dave,

I understood where you were coming from. The thread didnt get there until you posted. Thats why I was questioning the turbulence or whatever the downside. Thanks again.


DaveN,

That makes it more reason to not do it now. We already have enough flow at those points. Thanks.

[ROB DENENBERG]

With my cervanis hood on my 89SC it would run very hot on the gauge. After I taped off the openings in the front of the hood the temp came back down. This would happen at hwy speeds only. Have a feeling that air comming in the scoops hurt the air flow to the radiator.

[sail7seas]

I wonder if a dip in the hood would be possible/sexy.
Similar to the Ford GT. Perhaps photoshop a SC.
http://www.fordvehicles.com/fordgt/media_gallery.asp?gallery=PRODUCTION_PHOTO

[tim]

I have not done it yet because its still in the design stage. My idea is to pick up air from under the car and directt it to the radiator and intercooler. kind of like an air dam sort of, I thinK:confused: After talking to Dave I dont think my hood is really doing what I thought it did. Air flow is a tricky thing.

[1bad67cat]

Get radical and put a scoop like this on.

http://img.photobucket.com/albums/v218/1bad67cat/1bad67cat/1bad67cat.jpg

[392Bird]

I am 100 percent happy with mine.

http://members.tccoa.com/392bird/hoodsept4.jpg

Scoop feeds the air intake only.

[CougarXR/7]

I gave thoughts to venting hot air out with a NACA style scoops facing to the rear.

In the 60's and early 70's we did the "hood jack" thing.

[392Bird]

I gave thoughts to venting hot air out with a NACA style scoops facing to the rear.

In the 60's and early 70's we did the "hood jack" thing.

Yep, here is my old 67 GT taken in 1972.

http://members.tccoa.com/392bird/raisedhood.jpg

http://members.tccoa.com/392bird/rfrontgt.jpg

I sure wish I had kept it.

[5o4SHO]

I was actually going to post and ask about this too. But I was wondering, how much does this cervinis hood actually work? I've had it on there since I bought the car, so I cant compare how cool it was when the stock hood was on it. If it isnt THAT functional, I would like to put something under the hood like mesh or something to cover those holes in the front. It was pretty windy and raining here one night and I left the car out. Needless to say, I wake up in the morning and it got the whole engine bay wet, and it had leaves in it. My cervinis hood scoops openings are right in front of the alternator and IC tube. So, would it hurt to cover those up and just leave the rear ones by the windshield open? I try not to drive it in rain, but if I need to I dont want to have to worry about my DIS, alternator and other electricals getting wet and frying. Heres a pic of mine...I think this is the same one XR7Dave has.

http://i95.photobucket.com/albums/l127/lon01_2006/Oct08154.jpg

[SC Spyder]

Based on (limited) research I did on this subject a few years back, these are the things the "experts" I spoke with said.

a). The further forward on the nose of the car that the opening of the scoop is, the better because of turbulence on the surface of the hood. Also, the opening should be approximately 1" above the surface in calmer air, again because or turbulence caused by called the "Boundary layer".

Also, the further back from the front of the hood, the more turbulent the air is. Basically, as the body moves through the air, it forces the air apart and because air has mass, it tends to create a negative pressure or lift (Bernoulli’s principle).

b). The base of the windshield is a very turbulent but high pressure area, so it makes a good place for air intake. Why would you see oil/liquid on your windshield? My guess is because it has more mass than the air going the other way. (VW took advantage of this with their oil filled air cleaner, no paper element. When the incoming air turned a corner, any particulate matter with more mass continued to go straight into an oil bath).

I suggest, to see the air stream over you hood, tape small tufts of yard onto your hood and drive the car. Have a passenger look (or better yet have someone in another car record it with a camera for closer analysis).

And one more thing, there really is no "Ram" effect at normal road speeds. Any benefit is from cooler, less turbulent air in and/or easier exit for hot air.

Just my two cents.

Doug :o

[ThunderDave]

Get radical and put a scoop like this on.

http://img.photobucket.com/albums/v218/1bad67cat/1bad67cat/1bad67cat.jpg

Yeah, those old school snorkel scoops would be a bit much on an SC I think. But if you decide to go that way, just know that after about 40 mph, duct tape will not hold it on. :eek: ;) :eek: :D

[bowez]

Get radical and put a scoop like this on.

[IM G]http://img.photobucket.com/albums/v218/1bad67cat/1bad67cat/1bad67cat.jpg[/IMG]

Please tell me thats a Mustang hood and not a Cougar's

[Mike8675309]

As XR7 Dave stated, you need to pay attention to what you're doing when you attempt to do something like change air flow.

I've done quite a bit of uninformed research about this as I don't like how hot it gets in the engine compartment. I'm currently at a point in my research where I feel I need to identify the low and high pressure areas created by our car. I wish we had the Ford aerodynamic data for these cars, as you know they likely did some wind tunnel tests, or simulations at least.

Air flow through and around a car is a function of high and low pressure areas. For example, that air dam just below the lower radiator support not only helps direct air up, into the space above the radiator, but also creates a low pressure area behind the dam, helping to draw hot air from behind the radiator and directing it under the car.

An NACA duct is virtually worthless on our cars unless you are intending to hit some high velocities. The actual air flow that such things achieve is so limited below 100mph as to be something there just for looks.

If you could find the low pressure area that's created ahead of the windshield, you could vent the hood and possibly help clear air out from under the hood. But you'd have to be careful that it doesn't mess up an air flow pattern already being used by the OEM.

[mannysc]

my hood is open in rear air goes in scoops and out back of hood my under hood temps are close to outside temps my engine runs at the first mark below the w in warm on a 104 day. i ran a tracer " smoke cartidge " and it catches air and runs it out back of hood my radiator runs cooler than stock .

my car does not lift at speeds my ic is working good the air is flowing thru my radiator i have no pressure under hood the opening in rear is big as for water on the electronics BS it dont matter my dis gets wet all the time its sealed in jell water cant get in it i wash my engine all the time so water is not a bad thing .

oh yeah any drag on my sc and its C.D. are small if at all and any drag on my cars body by wind is small the damn antennea gives more drag then the scoop.

the scoops are in the slow moving air stream the air moves slow against the car it only moves fast at or above 3-4 inches above the stock hood .

as for effecient hood scoops not much can beat the mopars scat scoops such as the T/A scoops on 70 T/A challenger a great boundry layer scoop .

the AAR CUDA was not as effieciant nor was the raM AIR ON MY 71 CHARGER.

IT HAD A SCOOP that opened at wot and said ramcharger on it with narrling teeth. oh yeah i like my hood and would do it again to another sc .

[1bad67cat]

Please tell me thats a Mustang hood and not a Cougar's

Well, since it's a cougar, and the hoods don't interchange, it's a cougar hood.:) :eek: :D But it's mine, and the scoop covers the big hole under it.

[bowez]

To my understanding the early Cougars can use most of the Mustang parts. Hence the saying I'm fond of "All a Mustang is good for is parts." got it off the Classic Cougar forum or was it the Cougar Club of America.

[1bad67cat]

lol. i hadn't been over there in a while. cougars are actually a little longer. I don't think any of the body panels are interchangeable, without some fab work. with a welder, anything is possible.

[bowez]

.. with a welder, anything is possible.

Now your starting to think like a Cougar owner :)

[ricardoa1]

Would cutting holes in the hood above the SC top so that air flows under the hood help or would that cause turbulance. Im not talking about a major hole. Just something to force cool air over the motor.

You will simply create turbulance in the engine compartment, maybe to the extent where decreases cooling. Having a cowl hood will help with cooling when you are stationary but once moving, it will do just the opposite, it will suck air in and interfere.
The best thing to do is place reverse cooling vents or scoops facing the winshield. And you want to place them as far up as possible but far enough from the pressure area where the hood meets the glass. Something like the Y2K cobra R hood.