Fiberglass hood mods... crazy?

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dano said:
To reduce heat, you need a vent at the leading edge of your hood past the radiator. See Mitsubishi Evolutions as an example of this. Not to be critical, but your air intake is in one of the worst spots of the car, up high and next to the radiator, I know you don't have much to work with but, a cowl would work if you were to move the inlet to the firewall, I've seen this setup before on cowl hooded Mustangs with centrifugal blowers. If your trying to lower your intake charge by lowering your under hood temps, I think you have an uphill battle you'll never win without an intercooler or methanol injection.
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Reducing heat is not my main concern; reducing the trapped air inside the engine compartment, IS...

I agree with you that the air intake is in a horrible place, but there's no room between the grille and the radiator for a filter, and I put this thing together in a hurry, and haven't yet, figured out exactly what to do about that, but you're right; it MUST be moved!

I do have a SnowPerformance BoostCooler alcohol injector, set to start apraying at 3 pounds of boost. That and an MSD BoostMaster, boost-referenced inition retard have kept me out of detonation so far... on av gas.

Not much woirried about the underhood temps, as this engine runs prety cool; never overheats.

I may try to move the intake to the cowl; that's a great idea!!!
Thanks for your comments!
 
green1 said:
why do you think engine bay air is slowing you down?
Do you have a gauge in there?
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I think that al the air that comes through the radiator has to go somewhere... Have you ever been in a car that the hood came unlatched and blew up?

I have; there's a TREMENDOUS "lift" action at spped, that will blow the hood clean off the car...

I thought that maybe, if I could let some of that trapped air OUT, it might help the car's e.t.

I may be dead wrong, but, if I don't try, I'll never know....:read2:
 
Well, why don't you just make a few passes without the hood to test your theory before you cut up a hood?

My personal opinion is it isn't going to make a bit of difference.
 
I guess I am not quite sure what it is that your looking for here?.

You came to the thread asking questions and looking for answers and you brought an idea to the table and it seems that everyone that has given you ideas or given you an opinion on your idea......you have turned them down and argued on there points.

I am not being rude or anything here,don't get me wrong....just an observation.

if your looking to keep the car looking "bone stock" as you say......I guess I don't get what the difference is rather you have a cowl hood or you cut big ugly holes in the hood and put hinges on them...either way its not going to look stock and one of the 2 ways will not look good.

Sorry, I am just trying to be honest here...I don't see the point in cutting a perfectly good hood and even more so when your results from doing so will most likely not be that great.

I think out of anything, i would make a belly pan for the car.

That would drop any engine bay pressure significantly and maintain the stock look of the car.

And you could also cut a trap door in the belly pan for easy access to changing oil filter and what not ....you could even use piano hinges on the trap door if you like since it sounds like you really just want to put piano hinges on your car lol!!!!! ...J/K.

I personally would put a belly pan on the car and I would run ducting under the car and plum in into your air inlet for forced air....I did not realise your induction set up until seeing the pictures and I think you could REALLY benifit from the forced air ducting instead of moving in still warm engine bay air.

Just some thoughts and again...I am not picking on you or being rude here, just my .02 cents on the hole thing.
 
The engine bay is a low pressure zone, when hoods open unintentionally, the small gap created by the lifting of the hood to the secondary catch latch then creates a high pressure zone under the hood and reduces the high pressure at the windshield. The faster your going at this untimely event will generate more pressure. I think if you just want to evacuate trapped air in the engine bay, a wide, low long hood scoop would do it, but this created a high pressure situation in the engine bay and in some cases if done incorrectly may reduce cooling through the radiator. I think if you had a wind tunnel (or a bunch of industrial fans and a smog machine) you could put a medium sized lip at the leading edge of your hood creating a low pressure zone across the hood to a point and place a vent prior to the high pressure zone at the windshield and let it vent air out. NACA vents inserted backwards in the hood may cause a venturi (sp?) effect on your engine bay and could help suck out air.

For your inlet, I've seen people actually put the filter in the cowl vent area, kind of a cheap air box, but I bet rain becomes a problem.
 
IgotDUST said:
]I guess I am not quite sure what it is that your looking for here?.[/I]

I am looking to get the trapped air that comes into the engine bay through the radiator out of the engine compartment by giving it an escape route over and above (no pun intended) what exists, now (which is, out the bottom.)

Adding a belly pan would actually trap that air inside the engine compartment to a larger degree, giving it nowhere to go, and increasing the pressure inside the engine compartment, it would seem to me.

You came to the thread asking questions and looking for answers and you brought an idea to the table and it seems that everyone that has given you ideas or given you an opinion on your idea......you have turned them down and argued on their points.


I have examined what I thought were the plusses and minuses of each and every suggestion; that's what a discussion is for. The fact that I didn't see any alternative to what I am attempting with my "flaps" in the back of the hood is just my opinion... and is surely not proof that mine is the best idea; just my opinion, and you know what they say about opinions. I tried to explain why I thought the "flaps" would work better, in each case.

Beyond that, I'm not sure what else I could have done. I', no doubt, should have posted a picture of the engine to illustrate that it's supercharged and that it doesn't have a conventional air intake location. My bad...:angry7:

I am not being rude or anything here,don't get me wrong....just an observation.

I never take constructive criticism as "rudeness." I appreciate the input, and the honest effort you've made to offer valid suggestions. That's not rude at all; just an attempt to be helpful, and that's why I asked.


If you're looking to keep the car looking "bone stock" as you say......I guess I don't get what the difference is rather you have a cowl hood or you cut big ugly holes in the hood and put hinges on them...either way it's not going to look stock, and one of the 2 ways will not look good.

A cowl hood has a reverse-facing scoop that is usually over three-to for-inches tall... sometimes more. That is VERY visible from the next lane. The only thing sticking up on the "flaps" deal (above the original contour of the hood) will be the piano hinge, which is less than a quarter of an inch tall, and wil be painted the same color as the hood; not very visible at all, unless you're right on top of it... The slits will be very narrow and will be pretty much invisible unless you're looking down on them. Of course, when they open up, at speed, they will be VERY visible, but that's just for a few seconds, and after the race is under way.

Sorry, I am just trying to be honest here...I don't see the point in cutting a perfectly good hood and even more so when your results from doing so will most likely not be that great.

Well, as they say; you can't make an omlette without breaking a few eggs... LOL! There's no way for me to learn about this deal without doing it. For sure, it won't HURT anything. The cut hood will still keep 95-percent of the rain out (at least) and will continue to function normally, in all respects. If it doesn't help (and, it may not), I'll go to plan B and probably build that belly pan, but keep the flaps as a way to evacuate the air in the engine compartment that came through the radiator; it has to go somewhere, and the bellypan will preclude it going out the bottom, unless I put louvers in it, which is not really a bad idea, now that I think about it...

I DO appreciate all the time you've taken to help me wrestle with this problem.

Many heads are always better than one... :read2:

I think out of anything, i would make a belly pan for the car.

That would drop any engine bay pressure significantly and maintain the stock look of the car.

That'll be plan B... with louvers, pronanly, to keep from trapping the air that omes in through the radiator...

And you could also cut a trap door in the belly pan for easy access to changing oil filter and what not ....you could even use piano hinges on the trap door if you like since it sounds like you really just want to put piano hinges on your car lol!!!!! ...J/K.

I personally would put a belly pan on the car and I would run ducting under the car and plum in into your air inlet for forced air....I did not realise your induction set up until seeing the pictures and I think you could REALLY benifit from the forced air ducting instead of moving in still warm engine bay air.

What you say about carburetor air intake location is 100-percent true, and will happen. I built this thing in a hurry, and didn't give proper thought to the air intake for the blower.

Just some thoughts and again...I am not picking on you or being rude here, just my .02 cents on the hole thing.
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It never entered my mind that you were being anything but helpful...
No problemo!!! :happy7:
 
Guitar Jones said:
Well, why don't you just make a few passes without the hood to test your theory before you cut up a hood?

My personal opinion is it isn't going to make a bit of difference.
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You may be right; it may NOT make any difference, but the aerodynamic chages that would occur by running without a hood at all, would likely skew the results so badly that I would't really be able to tell anything concrete from the experiment... I don't KNOW that, but, that's my opinion...

Thanks for your input!!!:rock:
 
Alrighty then,glad theres no confusion lol.

And your right,the only way to know for sure will be to do it and learn from it....But I have thought about it and I think its doomed to fail for atleast one reason.

And that reason is...

At high speed when you want to evacuate this air pressure the most.

You will be moving so fast that the external air pressure will be more then that of the internal engine bay air pressure....meaning that the pressure from wind due to the increasing speed will be putting so much force on your "flaps" that the engine bay air pressure will have to be greater than...in order to open the flaps to release the pressure.

With that in mind,you would have to have some type of system to aloow them to open reguardless of exterior pressure.

Rather that system be,before you race...you manually open your flaps before a race and lock them into a stationary position.

Or you make a design where the "flaps" you cut in the hood are connected to lets say a choke cable inside the interior of the car under the dash or something.

That way when your at the line you can lean down,pull the cable and pop them open.

But I do not think that they will open on there own from engine bay pressures alone.

Just something to think about.
 
IgotDUST said:
Alrighty then,glad theres no confusion lol.

And your right,the only way to know for sure will be to do it and learn from it....But I have thought about it and I think its doomed to fail for atleast one reason.

And that reason is...

At high speed when you want to evacuate this air pressure the most.

You will be moving so fast that the external air pressure will be more then that of the internal engine bay air pressure....meaning that the pressure from wind due to the increasing speed will be putting so much force on your "flaps" that the engine bay air pressure will have to be greater than...in order to open the flaps to release the pressure.

With that in mind,you would have to have some type of system to aloow them to open reguardless of exterior pressure.

Rather that system be,before you race...you manually open your flaps before a race and lock them into a stationary position.

Or you make a design where the "flaps" you cut in the hood are connected to lets say a choke cable inside the interior of the car under the dash or something.

That way when your at the line you can lean down,pull the cable and pop them open.

But I do not think that they will open on there own from engine bay pressures alone.

Just something to think about.
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You may have something, there. It may come to that...

Do you know what a boundary layer is?

In case you don't, a boundary layer is a dead area that envelops the hood to a height of, say two or three inches, and has basically, "Dead Air" forming a blanket of air that isn't really going anywhere.

I am no aerodynamics expert (obviously!), but I have read several articles on the construction of hood-mounted air scoops that mentioned this "boundary layer," and all those articles say it exists and is a problem, mainly because it's different for each vehicle.

Look at a '68 HEMI Dart or Barracuda; notice how tall that hood scoop is?

The reason, is, to get it above the boundary layer, where it can be effective.

I am thinking (hoping, actually) that the boundary layer on the part of the hood that has the flaps that are to open with air presure from underneath, will NOT be subjected to aerodynamic forces that would hold them closed; that the boundary layer will be sufficient to provide a favorable pressure differential that will raise the flaps, at least, some, and let some of that air beneath the hood out.

One thing for sure; I don't really know enough about aerodynamics to talk inteligently about it (and, I am aware of that), so I will just have to cut and try, and if it doesn't work, then, I'll probably try something else.

If there's not enough air pressure under these flaps to push them open, then, it's my feeling, that it's not worth doing. I don't really think a manually-opened flap would be necessary IF there's really a need for evacuation of that underhood air.

Have a good weekend!!!8)
 
DANO said: "The engine bay is a low pressure zone,

I am at a loss to understand what forces are at work to create "low pressure zone" underhood, when the radiator is a big, gaping hole in the front of the engine compartment and the inertia of the air in front of a vehicle travelling at high speed literally shoves that air through the radiator and into the engine compartment. Why doesn't that create a high pressure area in the engine compartment? Where does all that air go? The only escape route for it, on a flat-hood car, is to exit underneath the car, which is another high pressure area. That's why cars "lift" at speed, unless they're fitted with some sort of ground-effects (chin spoiler?) I can't see that under-car areodynamic environment "sucking" air from the engine compartment faster than the radiator opening and 100+ MPH of pressure is filling it up.

What am I missing here?


When hoods open unintentionally, the small gap created by the lifting of the hood to the secondary catch latch then creates a high pressure zone under the hood and reduces the high pressure at the windshield. The faster your going at this untimely event will generate more pressure.

Thanks for that great explanation; it is dead-on, and I feel pretty dumb not to have realized that, long ago... Makes all kind of sense...




I think if you just want to evacuate trapped air in the engine bay, a wide, low long hood scoop would do it, but this created a high pressure situation in the engine bay and in some cases if done incorrectly may reduce cooling through the radiator. I think if you had a wind tunnel (or a bunch of industrial fans and a smog machine) you could put a medium sized lip at the leading edge of your hood creating a low pressure zone across the hood to a point and place a vent prior to the high pressure zone at the windshield and let it vent air out. NACA vents inserted backwards in the hood may cause a venturi (sp?) effect on your engine bay and could help suck out air.

I could do that, and it would probably work as stated, but I don't want a scoop (or, scoops) on my hood, for strategic reasons... LOL


For your inlet, I've seen people actually put the filter in the cowl vent area, kind of a cheap air box, but I bet rain becomes a problem.

I'd bet you're right... and I don't really need water inside that system.
I may run a vertical, 4" pipe in front of the front wheel, with some sort of labyrinth to keep the water out... but this car will probably never again be driven in the rain, so, that might not be an issue. I have to do something, though; where that pickup is located sucks, big time...

Thanks for all your good ideas! I do appreciate them!!!
 
Bill Dedman said:
DANO said: "The engine bay is a low pressure zone,

I am at a loss to understand what forces are at work to create "low pressure zone" underhood, when the radiator is a big, gaping hole in the front of the engine compartment and the inertia of the air in front of a vehicle travelling at high speed literally shoves that air through the radiator and into the engine compartment. Why doesn't that create a high pressure area in the engine compartment? Where does all that air go? The only escape route for it, on a flat-hood car, is to exit underneath the car, which is another high pressure area. That's why cars "lift" at speed, unless they're fitted with some sort of ground-effects (chin spoiler?) I can't see that under-car areodynamic environment "sucking" air from the engine compartment faster than the radiator opening and 100+ MPH of pressure is filling it up.

What am I missing here?
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Path of least resistance. It is easier for air to go around the nose of your car than to go through the grill, header panel, radiator, etc. What air does enter hits the back of your firewall and travels down and under the car. I think this is why most firewalls have a tapered or somewhat rounded firewall to floor board transition. In more modern cars a lot has been done to increase this flow, getting it where is need to be and getting it back out. Your radiator should be the only air access to the engine bay from the nose of the car. At low speed air can pass more easily, but at high speeds it doesn't. I think if you took a fan and put it next to a window screen, place it on low, the air will pass and the screen will not deflect, put the fan on high and the screen will begin to deflect and blow around the screen as not all the air can pass, the nose of a car acts the same way.

Under the car can be a different story, as you know it is not flat, plus stuff hangs down and causes turbulent air friction. Chin spoilers create a wake of sorts to limit air from entering the front and sides, to a point.
 
8)
dano said:
Path of least resistance. It is easier for air to go around the nose of your car than to go through the grill, header panel, radiator, etc. What air does enter hits the back of your firewall and travels down and under the car. I think this is why most firewalls have a tapered or somewhat rounded firewall to floor board transition. In more modern cars a lot has been done to increase this flow, getting it where is need to be and getting it back out. Your radiator should be the only air access to the engine bay from the nose of the car. At low speed air can pass more easily, but at high speeds it doesn't. I think if you took a fan and put it next to a window screen, place it on low, the air will pass and the screen will not deflect, put the fan on high and the screen will begin to deflect and blow around the screen as not all the air can pass, the nose of a car acts the same way.

Under the car can be a different story, as you know it is not flat, plus stuff hangs down and causes turbulent air friction. Chin spoilers create a wake of sorts to limit air from entering the front and sides, to a point.
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That's interesting. I once read a vignette about Smoky Yunick attaching a clear plastic hood to a '57 Chevy race car, and putting 1"-wide, 16"-long "streamers" attached to the engine at one end, to allow viewing at speed.

THE STREAMERS ON TOP OF THE ENGINE WERE BEING BLOWN FORWARD, from about 40 mph, on up...

I never could figure that one out, but it would seem to verify what you are saying about underhood air currents.

No matter; if the air comes in, and the only way out is to the high pressure area under the car it stands to reason, I think, that the underhood area would have more-than-atmospheric pressure due to WHATEVER comes through the radiator.

I may be dead wrong about that; I wish there were some way to test my theory without cutting up a perfectly good hood....

Again, Dano, thanks for your insightful and helpful comments; you are obviously well-versed in this "black art" (and, I'm not.)

Have a good weekend!!!8)
 
A good way to visualize what you are considering to modify and the effect is to think what would water do if it were to replace air? It's easier to visualize water as a dynamic vs air. Good luck and have fun, that's what it's all about!!
 
Dano asked, " what would water do if it were to replace air?"

It would all run out the bottom... LOL! Gravity always wins!!!!!!!!:cheers:

I know, I know... you have to be smart enough to disassociate the water's weight from the rest of the experiment.... Only kidding.:profilel:

Gasses (air, for instance) really ARE fluids, just in a less-dense form, so they act pretty much the same , when subjected to the same treatment (discounting the virtual non-compressibility of fluids.)

Thanks for the suggestion; it really IS food for thought!!!
 
If you want to evacuate air from under the hood and don't want to be obvious about it... why not cut out the sheet metal like everyone does to install big block headers in an A-body?

The air would just run through the engine compartment and out through those holes... and exit under the car.

Same result, without all of the though on "how to alter a hood"!
 
I still think the way I did my Dart hood worked without all the hassle. The hood would rise about 1 1/2" once you reached 55-60 mph and release the air pressure. Once you slowed down, the hood went back and you didn't see any modifications except for the taller hood pins. It was quick, simple and you didn't need to cut up a hood.
 
Blownfish said:
I still think the way I did my Dart hood worked without all the hassle. The hood would rise about 1 1/2" once you reached 55-60 mph and release the air pressure. Once you slowed down, the hood went back and you didn't see any modifications except for the taller hood pins. It was quick, simple and you didn't need to cut up a hood.
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I guess when you're right, you're right...

I have read each and every reply to my bizarre post, and have slept on it, and in the final analysis, all things considered (with no apologies to National Public Radio), I think this long hood-pin idea is OVERALL, the best idea. No cutting of hood, fender panels, nor any fabrication necessary (can you tell I'm L-A-Z-Y????)

That will be my plan of action; buy a hood and some long (tall) pins for the back; might even put one dead center of the line between the two back pins, to keep it from trying to "bow" in the middle, when the underhood pressure (if there is any) tries to lift it, at speed.

I don't really want to have to cut my inner fender panels, if I don't have to.

Thanks, Blownfish; I probably would never have thought of doing it this way... I'm not that smart.:angry7:

One final question:

I have no experience with fiberglass "anything," but, I know that they have a "street-weight" hood and a lighter, "race-weight" hood.

Is the "race weight" hood strong enough for this kind of abuse? I will be going a MAX of 120 mph...

Any opinions will be much appreciated!
 
Bill Dedman said:
I guess when you're right, you're right...

I have read each and every reply to my bizarre post, and have slept on it, and in the final analysis, all things considered (with no apologies to National Public Radio), I think this long hood-pin idea is OVERALL, the best idea. No cutting of hood, fender panels, nor any fabrication necessary (can you tell I'm L-A-Z-Y????)

That will be my plan of action; buy a hood and some long (tall) pins for the back; might even put one dead center of the line between the two back pins, to keep it from trying to "bow" in the middle, when the underhood pressure (if there is any) tries to lift it, at speed.

I don't really want to have to cut my inner fender panels, if I don't have to.

Thanks, Blownfish; I probably would never have thought of doing it this way... I'm not that smart.:angry7:

One final question:

I have no experience with fiberglass "anything," but, I know that they have a "street-weight" hood and a lighter, "race-weight" hood.

Is the "race weight" hood strong enough for this kind of abuse? I will be going a MAX of 120 mph...

Any opinions will be much appreciated!
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Sounds like your thinking a little more clearly now lol....I would also go that route before cutting up a good hood.

I had a chincy little pin down lift off hood that looked like it was an ebay hood or something....very little material,but probably just what you would need,I could left it off the car and spin in on 1 finger,thats how light it was...and it would lift VERY easy while driving down the road....mostly due to it having a cowl and wind catching it and lifting it....not because of engine bay pressures....this was on a non mopar car a few years back.

good luck with going about it the way you are talking!
 
Bill Dedman said:
I guess when you're right, you're right...



Is the "race weight" hood strong enough for this kind of abuse? I will be going a MAX of 120 mph...
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I never claim to be right, just opinionated.

This worked on my Dart, but I would play around on the highway to see how your hood will act at higher speeds before you take it down the track and have your hood come apart on you at 100+ mph.

I had a lift off hood from VFN on my Dart, it was light weight and easy to lift off. I only had four pins on it and never had any problems. The hood I have on my Fish is from US Body Source and it is noticeably heavier.

One thing I was going to do but never got around to was to drill another hole in the rear pins so I could move the pins down for normal driving to keep the hood from rising.

The first year or two that I had the fiberglass hood, I only had the front two pins to hold it on and I took a couple of those metal corner braces with the screw holes in them from the hardware store and dipped them in a rubber coating then screwed them to the front edge of the cowl so they angled forward just above the hood to hold it down. I just slipped the hood under them then used the front two pins to hold the hood on. My theory being it was faster to remove two pins verses four when I needed to remove the hood, I was only 19 so don't laugh too hard.
 
The knowledgeable respondent wrote:

"I had a lift off hood from VFN on my Dart, it was light weight and easy to lift off. I only had four pins on it and never had any problems. The hood I have on my Fish is from US Body Source and it is noticeably heavier."

Well, I don't want "heavy." This stock hood is a back-breaker to remove or install by yourtself. I am looking for something that will blow away if I don't put a brick on it, when it's off the car....

But, I realize that unless I opt for a carbon-fiber piece, I'll have to compromize... I'll need a certain amount of "structural rigidity" and "integrity."

I don't know how to contact "VFN." Or, what the acronym means, if anything.


"One thing I was going to do but never got around to was to drill another hole in the rear pins so I could move the pins down for normal driving to keep the hood from rising."

Excellent idea..... thanks!!!:cheers:

I'll let you know when I get this aerodynamic Frankenstein operational. Might not do a thing for the car, but it gives an old man something to play with... :love7:
 
Alright... Not to be a wet rag here.. But your running into a couple of problems...
First off.. You need to strictly define your goal. Is it to relieve underhood pressure? vent hot air? or make your car faster?
We can do all three of these things. But not exactly the way you had in mind.

First lets go over the reasons your idea will not work.
1. the pressure under the hood is Much less than that at the base of the cowl. For the reasons others have explained.
2. even if you could get it to rise up more the air would go into the engine compartment, not out.
3. As for the raising hood Idea.. All I can see that's really doing is acting like a big wing and creating drag... A LOT of drag. has anyone made successive passes with and without? id say you could lose as much as a tenth.

Other Ideas.
To make it run faster you could do a couple of things.
1. cold air. Ducting cool air in is a GREAT! way to cut your times.. it can lower it by more than two-tenths in some cases.
2. A belly pan would help and hurt... It would hurt the airflow out of the engine compartment. but would help smooth the airflow under the car. A different way of doing this would be a 3/4 belly pan(uncovering at the engine compartment. you could help the overall aero and the airflow out of the engine compartment by doing the 3/4 length and a front spoiler.. I'll explain the reasoning later. As I'm running out of time..

if you do decide to do the hood mod and it doesn't work... Send it to me! I could really use it! LOL! Sorry I had to stop mid-post but I have to get off.. I'll finish it next time I'm on. Hope this helps

Benjamin
 
I thought a front spoiler would help lower the air pressure under the hood, Since the air is not going under the front of the car as much as it would without a spoiler. Any air going threw the radiator would have less resistance to push right over the firewall and down under the car. Isn't this why NASCAR racing uses front spoilers to help keep the front end low plus lower any underhood pressure so the front of the car does not lift. Just my opinion.
 
Sorry if I wasn't clear.. A spoiler WILL help the air get out.
I'm on a faster computer now so I can see your setup...
As for the induction setup.. why not just turn it upside down? so that it's pointing down and coming out in front of the radiator? if you did the spoiler with a intake "hole" you could have high pressure, cool air also. + a front spoiler will help with drag too, actually decreasing your CD.

I think if you want to evacuate the air out of the engine compartment you'll need to move the flaps forward. away from the high pressure cowl/lower windshield air. and if the boundary layer doesn't mess it up the Bernelle(I'm pretty sure this is spelled wrong) principle should raise them up for you.
 
bjkadron said:
Sorry if I wasn't clear.. A spoiler WILL help the air get out.
I'm on a faster computer now so I can see your setup...
As for the induction setup.. why not just turn it upside down? so that it's pointing down and coming out in front of the radiator? if you did the spoiler with a intake "hole" you could have high pressure, cool air also. + a front spoiler will help with drag too, actually decreasing your CD.

I think if you want to evacuate the air out of the engine compartment you'll need to move the flaps forward. away from the high pressure cowl/lower windshield air. and if the boundary layer doesn't mess it up the Bernelle(I'm pretty sure this is spelled wrong) principle should raise them up for you.[/quote]

I spent an hour writing a rebuttal to your previous post, but the wonderful world of electronics first hung it up, and then deleted it for me; I'm not going through that drill, again.

The distance from the base of the windshield to the back edge of the hood varies from 10" to 11," across the width of the hood. I am of the opinion that that distance, coupled with the cowl louvers that are a part of the heater system, will be sufficient to defeat any high pressure area that exists because of the aerodynamics of the greenhouse/windshield considerations. In other words, any high pressure that exists at speed, will be dissipated by turbulence before it gets to the area where the hood begins (as I said, 10-11" before the windshield.) The boundary layer on the hood will be above the area that will be exposed at the rear, because it will be headed upward, clinging to the hood contour, and will be above the opening, when the rear of the hood rises which could be as much as two to three inches.

That's my story, and I'm sticking to it!!!

And, yes, I definitely need to fabricate and install a chin-spoiler for this ol' tub.
That can only help, I think.

Thanks for all the thoughts and ideas, guys.... I am getting quite an education!!! :profilel:
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