How does it work?

okay, I know a cowl induction won't typically work with a maxima, but I figure most people who post here may have experience with other cars, and some of those worked with classic american steel, and muscle cars.
typical consensus says that there is a high pressure area that builds in the cowl, and the CI hoods allow some of that pressure to be relieved into the engine, but this logic seems a little flawed to me.

as a smoker, I usually smoke when I drive. I crack the window about an inch or so, and all the smoke gets sucked out through the window (well, my non-smoking friends disagree, but the smokers know what I mean). I can only see the flow of air doing the same thing to the engine: sucking air out of the engine compartment.

I have been racking my brain trying to figure out how these hoods help add power (as some claim they do) and the only thing I can think of is they create a duct for the air that passes by the intake, allowing a cooler, more forceful flow of air to be inducted, rather than the air that has been lingering in the engine bay, warming up, or being forced out of the bottom of the bay.

please alleviate some of my ignorance, if you show me pictures (and videos) I may just get it. I like to think I am a smart guy, but I can only go off what I know (or think I do), to help me judge a fact. this is a subject I am lacking in.

And I know they look cool, but do they do more than that, or is it a power adder, kinda like ricer stickers?

 

Cowl induction is when the back of the hood next to the windshield is open so that the intake can get access to the cool high pressure air that builds up there once the car is moving. basically a cold air intake for air filters that mount on top of the engine. obviously this doesn't apply to maxima's because our throttle bodies and mounted toward the side of the car.

 

Have you seen a windtunnel test of a car? There is an area directly behind the car where the wind will curve back on itself. This same effect, only a little smaller, is created at the base of the windshield with a cowl hood. At least that is my understanding.

 

see, that is what I mean. the reason the wind whirls there, is because there is a vacuum (low pressure area) in the back of the car. the air swirls there because it cannot pull the air through the car, but has to pull it from around the car. since the air can be pulled through the engine bay, it would seem to be using the principle I mentioned earlier.

allblackmax96: thank you. I knew there was a performance bonus, and I believe you, as well as I can.

I am still having trouble wrapping my head around the physics of this.

and I appreciate you, too johnmandude. I know I may seem argumentative, but I just don't seem to get it.

like i said, pics or vids. I am a visual/hands on learner. and since I can't think of a way to make this training hands on (and not break the bank in the process), I am asking for help.
I googled for about an hour, and I know how to use it, but the results were less than fulfilling. (all the links, no matter what search string I used, were forums discussing what looks good, or e-catalogs for suppliers of CI hoods.)

and pardon me for lengthy posts, but I want to get this, and vagueness on the part of the questioner never ends well

 

 

dude forget diagrams and low pressure high pressure all u need to do to understand it is visualize what happens when u open the door on an airplane

 

exactly, what I mean
so the air is drawn thru the engine compartment by the intake and out the cowl.

 

Er, as I recall from "back in the day", the 'murican cars with cowl induction had a backwards facing scoop with an opening into the carb, and a blocking plate around everything so that the engine compartment air would not flow into the carb. This was the source of cooler air with cowl induction. Same idea of a blocking plate was also used with front-facing hood scoops...

Any other old guys left over from the muscle cars days probably will remember these things. You had to separate the engine heat from the carb intake, or you ran super-lean on launch.

Personally, I'm now running with an air intake pulling air from under the front of the hood straight into the K&N and on down the line. Seems to work well for me.

 

fwiw the best hood imo you could buy is the invader style cf hood.
cf says weight
and vent is DIRECTLY behind the rad and sucks tons of hot air out of it which provides for better cooling and less heat into the engine bay and to your air filter.
while it doesn't do a whiole lot i believe it's better then stock.
then again i have one

btw grey nice ride.

 

no, air is drawn into the engine bay through the cowl most cars with a working cowl use it as the the air intake i saw one aftermarket cowl that actually opened up when you stepped on the the throttle to let more air in based on how you pressed on the the throttle so air is entering the engine bay much faster and less obstructed than through a grille but it doesn't cuase the aerodynamic drag that a hood scoop does

 

you seem to be contradicting yourself. you said above to think about a plane with the door opened. you get sucked out. ergo, my previous statement.

 

Ok Ben, I did some searching (try cowl induction science) and found an aerospace engineer that explains that the base of the windshield is a high pressure area and th eengine compartment is a low pressure area. Cowl induction works because the high pressure air (which is also cooler outside air) is pulled into the cowl by the lower pressure of the engine compartment, a vacuum effect. We all know that cooler denser air produces more HP. The cowl induction pulls cooler air at the high pressure area at the base of the windshield by using a vacuum of low pressure. That is my understanding.

 

I did not think to use the term science as part of a seach.thanx john. I had been under the impression that the opposite was true. and that was what I was getting from the responses so far.

 

ROFL ^^

GJ d-(^_^)z