Heat extrator vs cowl hoods
 

Which cools better? i get how both work. . and i need a hood at least for the cooling effect because i need all the help i can get . . but i wanna know exactly how much each one cools compared to the other . . . anyone know?

Heat extracter hoods extract heat while cowl induction hoods are actual ram-air hoods. It seems odd but look the '70 Chevelle SS. So if you want something to cool your engine bay, your only choice for hoods is a heat extracter type.

That's not true. A ram-air hood would by deffinition require the hood to be able to contain on coming air/wind and then force it into the engine compartment or an intake ie Pontiac's ram-air hoods they used on certain Firebirds and I think some GTP's.

A cowl hood allows the hot air that accumilates at the back of the engine bay near the fire wall to escape there by cooling the engine compartment. Think of it as this:

Car A without a cowl hood is travelling in this direction---> Hot air tends to rise and the actual movement of the vehicle forces air to the rear of the engine compartment.

Now Car B with a cowl hood traveling in the same direction---> With the cowl hood the opening at the back of the hood allows the air that is being pushed back and up by heat and movement to excape.

So to answer the original question I would personaly run a cowl hood. Ever wonder why pro 5.0 cars and so on run cowl hoods and not heat extractors? This is why they are taking advantage of the air's movements to extract itself from the engine bay.

wait wait wait, your saying that the cowl lets air out at the opening? because im pretty sure thats were the air goes IN. because the air comes up over the hood and gets pulled in the cowl and the hot air goes down under the car. .

No you have it backwards. As a car is moving forward air is forced from underneath it, up. A cowl induction hood allows that air and the heated air that results from the engine and exhaust etc. to escape. Therefore dropping underhood temps.

Say this is the hood and windshield (] I (=front of hood ]= back of the hood with the cowl induction and I = the windshield


Now car is traveling <---- in this direction therefore air is being pushed the opposite way ---->

Air
----> ( ] I
Now the air cannot just take a uturn once it hits the windshield and be pulled into the engine compartment. It just doesn't have that ability, once it hits the windshield it is actually reflected upwards.

Do you get it I know this diagram isn't the best but it's the best I can do for you right now...

here is what cuban i think is saying....cowl takes the movement of air through the engine bay, and lets it take it's natural flow of movement up and out, thus why the cowl hood is effective in letting hot air escape.

blue = cool air
yellow(imagine it was inside the engine bay) = air heated up by motor, escaping and being pulled by the cool air outside the car.

What he said LOL

For looks alone i would get a cowl hood on your car. And if you were smart you would of grabbed one for cheap from FFW.

Also cowl hoods make a low pressure spot in front of the windsheild and actully pull air in. it doesnt push air out. While you would think thats what would happen it doest. On my F150 when i had an aftermetket hood it had a nice raise in the back (around 3") and the truck ran constantly 10* cooler at operating temp. And cooled down alot faster too.

i thought the lower pressure spot created on the windsheild is what allows the hot air to be brought up and thus pulled into the cool air that is streaming over the car, in turn having the hot air pulled out of the engine bay, creating cooler temps.

here is a pic of what i mean.

blue = cool air
yellow = heated air
green = low pressure spot, allowing the hot air to come up and out of the engine bay, thus getting pulled away by the cool air.

How useful is a cowl hood in traffic? I have the heat extractor with 4 vents two just between the radiator and block two in the rear. When Im parked with car on or off I can see the heat coming out of the vents IMO this will be more useful in a street car.

exactly what i thought was the idea, expecually because i thought the carb guys <3 cowl hoods because the low spot forces air towards the carb


so the question stands, which COOLS better heat extractor or cowl?

I would bet money idling in traffic the cowl is better as its just gona let the heat rise and go out the back of the hood (the fan will help push it back there too). While moving i think i would still go cowl. I dont see the heat extractor being that good at actully extracting alot of heat. Its more of a design name. It helps dont get me wrong but cowl would be my choice hands down and will give some room too. Maybe for some nitrous noids on that manifold?

Nope. Just look at the all drag cars equpied w/ a cowl induction hood and a carb'd engine. They have the carb enclosed in the hood so the air coming in from the cowl is forced into the carb. It seems very odd but it is a type of ram-air induction. There's a reason why Chevy was more prone to use cowl induction over hood scoops (works the same but their designers thought it looked better).

I guess cowl hood it is, now i have to choose double hump cowl or classic cowl, 2.5 3 or 3.5" . . im leaning twards classic 3.5" cowl. . .

Watch out w/ laws since if there's laws against having anything hang from your rear-view mirror, there might be one for cowl size.

damn . . i have stuff hanging from my rearview window . .

http://www.cervinis.com/product.aspx?car=1&id=1127

double hump gets my vote.

I think im going to go with a Kaenan hood (sp?) since they are local in melborne, i can just pick it up.

The LS6 Chevelle's Hood worked as a true cowl induction cause it had a shroud underneath that sealed to the carb. and i believe it worked of vacum and used the air of the windshield, unlike many of todays Cowls just provide a rise for more room underneath wich provides i guess better cooling for the engine also? i personally think they look awesome on our cars especially the 98 cobra r hood w/ 2.5 in rise.

Also a very nice choice of hood sir. Love there cowl for our cars.

Got a pic? Im not sure if i know that one...

Edit, nevermind i found one...What kind of rise are you gonna go with?

As a resident popo here in Utah, our rule is nothing bigger than 4 inch for cowls due to the amount of visibility they restrict. So be carefull and check what the local rule is on things. Let the import guys generate all the negative publicity and become the targets of the police and not the Muscle cars. :attention_whore:

Im thinking 3.5" single cowl, or double . . not sure yet . . but 3.5" seems to be more then your adverage 2-2.5 but not big enough to be stuipid big.

and stngmn96, thanks for the info, the cops are generally lax arround here as far as stuff like that goes. A guy in my car club has a 5" cowl on his mach1.