RT VS. COWL hoods

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Newmans Own

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For those with more experience than I, I'm hoping to figure out which hood will give me greater airflow. I have a Pro Flo Edelbrock 14" round air cleaner with breathable lid and was wondering if open nostrils in an RT hood would allow more air in than a 3" cowl hood. Hood will be on a 92' D150. I don't quite understand the science behind a cowl hood. Any help would be appreciated!
 
This article will give you an idea of the basics of the cowl hood induction theory:

http://www.hotrod.com/how-to/engine/1301phr-cowl-induction-cold-air-system/

Basically, a properly sealed air cleaner in a properly designed cowl hood system would draw fresh, cool air from the base of the windshield, instead of the hot air inside the engine compartment.

The R/T scoops would drive fresh, cool air into a properly sealed air cleaner assembly, as well.

The trick here is "properly sealed". Just dropping an R/T hood (or any scooped hood) on a car isn't going to do much of anything by itself. The air cleaner must be sealed off from the hot engine compartment air and be drawing in outside air from the scoops or cowl to be effective.

I think you'll find that most folks run the cowl hoods for increased clearance for high-rise intake manifolds. IMHO, neither the cowl hood or the R/T hood is going to make much of a "seat of the pants" difference in a street-driven car (or truck). They sure do look good, though!
 
Thanks for the words of wisdom! I think I've come up with a great plan. Spectre has 2 intake kits a 762 (dual cannister) and a 7168 (with a 16" air hat). Right now I need performance and I believe either one of these are my best solutions for cold forced air! I just need to see which one has more air flow. I still want a custom hood but it's purpose will be for show and nothing to do with flow. thoughts?
 
ever open your vent doors and have cool air blow up your shorts? Thats coming from the cowl area...now put that flow into your carb. There is higher pressure at the cowl region than over your hood, unless you get the scoop a few inches above the hood off the stalled air (snorkle style) or depressed, under the hoodline (NACA ducts).
 
I have seen a few cars with cowl induction in which the air cleaner cannister is ducted straight back into an opening cut into the fire wall that feeds directly from the cowl. No hood scoop. I think this was the old school NASCAR style. I don't know if it is used in the same way today.
 
Damn, every time I figure it out I get better ideas. Try to picture this.....cowl hood, sealed air box sitting atop my throttle body, two bent 4" pipes running out eifher side offje airbox backwards and up to the opening of the cowl with two conical filters facing each other nose to nose. From the drivers seat looking through the windshield you would see two filters laying sideways facing each other. Does that make sense or am I trying too hard now? There Definately is mega air coming off the windshield.
 
I was also thinking of plumbing directly off the front. If I cut holes in the metal on either side of the rad, those holes open up directly behind the front grill where there should be tons of air. Tubes from those holes plumbed all the way back to a sealed air box.....thoughts?
 
Newmans Own said:
Damn, every time I figure it out I get better ideas. Try to picture this.....cowl hood, sealed air box sitting atop my throttle body, two bent 4" pipes running out eifher side offje airbox backwards and up to the opening of the cowl with two conical filters facing each other nose to nose. From the drivers seat looking through the windshield you would see two filters laying sideways facing each other. Does that make sense or am I trying too hard now? There Definately is mega air coming off the windshield.
Click to expand...

Skip this ^^^^^
 
Newmans Own said:
I was also thinking of plumbing directly off the front. If I cut holes in the metal on either side of the rad, those holes open up directly behind the front grill where there should be tons of air. Tubes from those holes plumbed all the way back to a sealed air box.....thoughts?
Click to expand...


I'd skip this ^^^^^^^
 
dozer556 said:
This article will give you an idea of the basics of the cowl hood induction theory:

http://www.hotrod.com/how-to/engine/1301phr-cowl-induction-cold-air-system/

Basically, a properly sealed air cleaner in a properly designed cowl hood system would draw fresh, cool air from the base of the windshield, instead of the hot air inside the engine compartment.

The R/T scoops would drive fresh, cool air into a properly sealed air cleaner assembly, as well.

The trick here is "properly sealed". Just dropping an R/T hood (or any scooped hood) on a car isn't going to do much of anything by itself. The air cleaner must be sealed off from the hot engine compartment air and be drawing in outside air from the scoops or cowl to be effective.

I think you'll find that most folks run the cowl hoods for increased clearance for high-rise intake manifolds. IMHO, neither the cowl hood or the R/T hood is going to make much of a "seat of the pants" difference in a street-driven car (or truck). They sure do look good, though!
Click to expand...

Re read this

then click on the link and read that.

DFX 340 Duster said:
I have seen a few cars with cowl induction in which the air cleaner cannister is ducted straight back into an opening cut into the fire wall that feeds directly from the cowl. No hood scoop. I think this was the old school NASCAR style. I don't know if it is used in the same way today.
Click to expand...

This is an option. I'd skip it myself. A lot of work cutting into the metal. But it does work excellent.
 
Rumblefish, I had read the article in that original post and it was awesome! I just don't really have any means of fabricating it myself. Unforunately with a new born and money tight, I was looking for a simpler solution that would find me with some gains. Rather than fabricate like in the article, could I simply have a sealed 16" air hat and plumb a 4" pipe from the hat through the fire wall and into the induction spot under the slots and at the base of my windshield?
 
Check out the 64 thunderbolt. It seemed to have worked for the other guys
to some extent back then? Could possibly be self done easier on the cheap
than some of the mentioned ideas here.
 
Newmans Own said:
Rumblefish, I had read the article in that original post and it was awesome! I just don't really have any means of fabricating it myself. Unforunately with a new born and money tight, I was looking for a simpler solution that would find me with some gains. Rather than fabricate like in the article, could I simply have a sealed 16" air hat and plumb a 4" pipe from the hat through the fire wall and into the induction spot under the slots and at the base of my windshield?
Click to expand...

Yea you could! That article was a bit involved in its workmanship! Wow!
Your idea so far as I understand it basically replicates that idea in a simpler fashion.
What is the goal of the car? I ask because there are a few things in the way of this idea making the instal not so easy. Moving stuff around is easy, just a pain. Then there's the wipers.....
 
Thanks SSBA, I'll check that out for sure, and Rumblefish, my magnum 318 runs so strong right now that I can't justify a re build. I'd love a 408 stroker one day. For now I'm just trying to get the most with simple bolt on. I've got shorty block headers and full exhaust, electric fan, throttle body spacer, jet performance chip, pulleys, and now just need more air.
 
I hear ya brother. Rebuilds are expensive and adding a strikers rotating assembly on top is a lot of bread.
 
Any of you interested in Comin up to Canada to ride on the hood of my truck to see if I'm getting the suction I want by holding your hand over my cowl?! I got a blow up mattress in the basement and my wife makes a mean pasta dish!!
 
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