Hood options

[James4086]

Ok, so I know about the SLP heat extractor hood, and there was a vendor at C5F with a cool modular designed hood that could be "ram air" or heat extractor, or clear or carbon fiber in the center.

that's cool and all but....

I was wondering if anyone had seen a difference in engine temp afterwards, and have some actual proof that it works.

I'm new to all this, so I'm not by any means an expert. However, these are some points I'd like proven:

First does any air pass through the "functional" hood scoop on the ram air hood scoops. I saw a special on the old GTO, and they said when they added the hood scoop to the car, it was utterly useless because the air hit the front bumper and went over the hood, so there was no rammed air.

A friend of mine has the old stingray, beautiful car, and he said that the "ram air" hood that they added to the stingray in later years caused a loss of power. This is because the origional cowl hood would let the air that hit the windshield fall into the engine bay, and the ram air setup blocked it.

This makes me wonder what would happen if we cut-out the little rubber gasket at the back of the hood. I think you'd have problems with rain water getting into places where it shouldn't be, but IDK, that's why I'm asking.

Of course the people who sell the hood will say it that air does pass through, but I wanna see a wind tunnel (with the full car in it) or some kind of conclusive proof that the air is pushed into the hood.

Next, the stock hood is aluminum; so IF the ram air and heat extractors don't force the air through the engine bay, wouldn't an aluminum hood be a better heat-sinker than a fiber-glass hood with a small hole?

Like I said before, I'm new to this, so there may be a simple explanation here that I'm not seeing. Otherwise, I'd like to see conclusive proof one way or the other. Preferably with wind-tunnels and smoke trails etc. However, I'm sure not everybody has access to such resources... I know I don't.

[SILVER BULLITT]

Well its pretty self explanatory that if there is a good size whole in your hood ( 14in. x 3.5in.cowl hood) air will be passed by it and through it . as far as I see it any cooler air movement or heat extracted is better than none . it might not be a 50 degree difference but every degree counts ! especially if you are supercharged . talk about heat sink ...... as far as a test im pretty sure you wont find one done with smoke in a tunnel of air but im sure if you were to run a thermo test there would be a difference not only in the motor temp but also in the temp of the surrounding things around it ie: the hood , fender wells, fire wall, etc.... remember a little air movement is always better than none .

[2010 SSRS]

I'm waiting for the big cowls to come out.

[James4086]

I agree with you completely, any air movement is better than none. However, my problem is that I don't want to go spend $500 on a new hood that doesn't actually do anything better than the stock hood. In other words, I don't want to buy a heat extractor hood made of fiberglass if it is less functional than the stock aluminum hood.

I am planning on supercharging, (just sent in the check), but I'm not the owner of an aftermarket shop, or someone who still has both hoods to do a test. That's mainly what I'm looking for here. I do want to buy an aftermarket hood, preferably one that reduces heat in the engine bay. However, I want hard proof that it works first.

As I said in the first post, IF a fiberglass hood doesn't move the air any better than the aluminum hood, then the aluminum will do a better job of reducing the heat. Also, even IF the fiberglass moves the air, it still has to move enough of it to reduce the heat better than the aluminum hood.

[James4086]

[Rockin the BlueSS]

ok here we go, i would like to say that i am in now way affiliated with any hood company. i am a mechanical engineer and this is just my thinking using what i wave been taught and seen in some tests.

as far as the hood scoop not getting any air:

when a car moves through a compressible fluid (air) it build a boundary layer that deters the fresh fast moving air from directly contacting all parts of the car. this event is described in the first picture and demonstrated in the picture of the viper...



the large gap between the hood and the stream of smoke is i believe leading you to think that the scoop would not get any air... but if there was a hole in the hood with a positive suction (like a sealed intake pulling air in) the fluid dynamics gets a lot more complicated. From this image you can see that there smoke entering the "slot" in the cowl but at this point every application can be different. i believe this is the reason dragsters put the intake so high off the surface of the car. but like i said with the positive suction and cooler air coming from somewhere other than the engine bay it should see a performance gain. and there have been many debates on this site and other about the possibility or "ram air" intakes, at the speed the cars are moving it really is not fast enough to get the pressure needed to give a ram effect. so the idea is just to allow the intake the most non-turbulent coolest air it can get...

Now for the vents:

judging from these to images



and the fact that the grill on the camaro is much more of a wall, it would tend to move the air very well through the engine bay. this redirectio on of the air path can/will have two effects. one the heat will be carried out of the engine bay as it was designed to do. but in addition it will changed the basic shape that the air must travel around.

by having the air able to pass through the grill and then leave from the hood the air will take a path less like the top illustration of a "flat plate" and more of an angled surface...

these are my thoughts on the subject...

[James4086]

Thank you, this was very helpful!

[robrr2000]

What this picture shows me is that with the amount of heat coming of the engine, this style of hood would be excellent for defrosting our windshields.

[James4086]

Originally Posted by robrr2000

What this picture shows me is that with the amount of heat coming of the engine, this style of hood would be excellent for defrosting our windshields.

LoL defrost is one thing, but I like the cooler engine as well. I would love to see a similar hood with like 8 cowl slots (one for each piston lol) or 6 slots for the camaro. Also, I would like to see it made from carbon fiber (the kind that can be painted if there's a difference) or aluminum.

The best thing (IMHO) would be to take the stock aluminum hood and find a way to put the cowl slots into it and still keep the professional look, that way you don't have to buy a new hood, and you keep the stock center cowl.

Any of you vendors, aftermarket shops or someone who could do this PM me if you have something like it, or can make it! LOL

[ipimpthisc]

bump...i am in