Psycho Mythic
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Has anyone done this? Been thinkin about modifying my passenger side brake air duct up to the bottom of an intake box. What do ya think?
OEM Ram Air Brake Ducts modified for Intake?
- Thread starter Psycho Mythic
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ARRESTmeRed04
Active Member
I think you would be better off cutting a hole in the air box and going from the grille like trainman
Yeah it's been done, I can't remember who did it, that's what my plan is to do this winter/spring when I put my inner fenders back in.
Psycho1122
Full Access Member
Ram Air......
The factory system for cold air feed works very well.
The primary secret to "Ram Air" is to SLOW DOWN the cool air. By putting a "scoop" pushing air strait into the box defeats any amount of ram recovery. Air under high velocity has LOW volume.
The factory scoop takes the high velocity, low volume air and "recovers" pressure with volume by allowing the incomming air to the fender to expand and fill the "box". The filled box has higher volume and pressure than whats comming in via the grill scoop. Just think about hydrodynamics. You have all done it with a garden hose. Turn on the water full and let it flow into a barrel. Now take your thumb and patially block the end. You have more water velocity, but lower volume and thus the barrel will fill slower.
The engine then draws from the cool, positive "box" fender chamber. If you have ever looked closely at a removed fender, the factory guys put a sound deadend baffle mid fender to help determine "box" volume. This area, even though it is not completely sealed can achive pressure equal to ambient at speeds as low as 40 m.p.h. As a test, I will eventually install a pressure sensor from a ram-air motorcycle to help determine at what speeds the fender "box" area starts to produce positive (above ambient) pressures. I would not be suprised to see over ambient by 120 m.p.h. However, the huge benefits of the fender area filling with cool, charged air equal to ambient are realized at the engines intake hole before the filter.
Ramming it strait in would yield the opposite result. Cool air in... Yes. Additional volume or positive charge....No. See the Primary rule above.
Cheers Guys!!
The factory system for cold air feed works very well.
The primary secret to "Ram Air" is to SLOW DOWN the cool air. By putting a "scoop" pushing air strait into the box defeats any amount of ram recovery. Air under high velocity has LOW volume.
The factory scoop takes the high velocity, low volume air and "recovers" pressure with volume by allowing the incomming air to the fender to expand and fill the "box". The filled box has higher volume and pressure than whats comming in via the grill scoop. Just think about hydrodynamics. You have all done it with a garden hose. Turn on the water full and let it flow into a barrel. Now take your thumb and patially block the end. You have more water velocity, but lower volume and thus the barrel will fill slower.
The engine then draws from the cool, positive "box" fender chamber. If you have ever looked closely at a removed fender, the factory guys put a sound deadend baffle mid fender to help determine "box" volume. This area, even though it is not completely sealed can achive pressure equal to ambient at speeds as low as 40 m.p.h. As a test, I will eventually install a pressure sensor from a ram-air motorcycle to help determine at what speeds the fender "box" area starts to produce positive (above ambient) pressures. I would not be suprised to see over ambient by 120 m.p.h. However, the huge benefits of the fender area filling with cool, charged air equal to ambient are realized at the engines intake hole before the filter.
Ramming it strait in would yield the opposite result. Cool air in... Yes. Additional volume or positive charge....No. See the Primary rule above.
Cheers Guys!!
So all of the Ram Air pontiacs and other muscle cars and the current Pro Stock cars have it all wrong? I have a ram air duct straight into my Volant box from behind the grill.....and I have consistently had higher MPH than any of the other NA trucks on this site...so I must disagree.
phxpoolguy
Full Access Member
I agree, sometimes its possible to over analyze a solution. My feeling would be the colder the air and more direct path would be the best solution.
you have it running into a box first... so your setup is proof that what Psycho was saying is true.
if i ran 4" dryer hose directly into the TB, i think it would have a negative effect, for example.
Psycho Mythic
Full Access Member
Well for one I NEVER hard brake my truck, don't like to put the pressure on it, or the brake dust 
Secondly, I like what trainman has done, I'll more than likely run stock air ox with a k&n, just to try it run some duct from the brake duct to the bottom of the box, and rig something as trainman has as well...
Secondly, I like what trainman has done, I'll more than likely run stock air ox with a k&n, just to try it run some duct from the brake duct to the bottom of the box, and rig something as trainman has as well...
ARRESTmeRed04
Active Member
Man your over thinking it with the brake duct, just go from the grill, its a straight shot...
Psycho Mythic
Full Access Member
Haha probly so :vollkommenauf:
Psycho1122
Full Access Member
No. OEM's do not have it wrong. Most of the systems do a very nice job of getting cool air into the engine. Ram pressure above ambient?!? Hard to say. Of the older muscle cars that had systems that worked the best were Chevy's with the cowl induction hoods (NASCAR still utilizes cowl feeds today). It's one of the more areodynamic ways to grab high velocity, dense air. Some older tests showed the Mopar "Six Pac" and "Air Grabber" hoods most efficient due to how high above the hood the air was being captured.
Our trucks are also grabbing air from a high pressure / dense area at the front of the truck.
But just a "slice" of it.
That is whats critical about Ram recovery. The primary opening of the "scoop" needs to have less square area than the intake of the "airbox" (our filter box). After the primary opening, the tube or "scoop" needs to GRADUALLY increase in area to slow down the charge, just like the modern scoops on Pro Stock drag cars. Small opening, scoop gradually enlarges towards the intake. Pro stock scoops are also placed up, out of the dirty air comming over the hood to get the least turbulent "slice" of air. Not only is this paramount, it's VERY cool and efficient!! Plus, they really can take advantage of the free boost above 120 m.p.h. as they scream to 200+:rock:
All I was stating was.... our trucks have a very well engineered intake system. Since we are not grabbing our slice of air from a non turbulent area like a Pro Stock scoop, the engineers did the next best thing by filling the fender area with dense, high speed air, slowing it down and recovering pressure for our airbox to draw from.
Trainman; you do have impressive trap speeds. A result of good horsepower, excellent driving and I really like your grill block off's. I would not be suprised if you revised your block off to allow the air to go into your fender and draw from there, that you would pick up additional trap speed. There is just not enough volume in the filter box to recover pressure from the high velocity air being crammed into it.
Cheers Guys!!
There is a scoop directly behind the opening of the "grill block-off" that rams straight into the Volant Air Box, it doesn't really go into the fender.I used an old brake cooling duct to form the scoop. There is a square opening right in the front of the Volant box that the scoop rams air directly into the box. I have used that for about 5-6 years.
SrtBrad
Michel Productions
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i did and picked up alot on the sotp dyno that is used in the carolinas
shikityshack
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What is your oppinion of the Mopar CAI system for these trucks then? Since it doesn't utilize an air box..
VENOMOUS1 RACING
Has Left the Room - Banned from VTCOA!
Inside the fender area is stagnant warm air ! Not dense cool air by any means. Almost all factory cars do this since way back to silence the intake of air through filter and into carb/throttle body. The classic "whhoooommmp" sound when you stomp any size engine car WOT is silenced by running the drawn air from the inner fender. Hence why all CAI pull the intake from the fender and into cooler air ( some just suck hot engine air, lol). Add a CAI of any make and really hear the "whhoooommmp" from your engine sucking in air suddenly once blades open.
A well designed intake and filter system can provide POSITIVE pressure into an engine and has done so for decades. You may not get quitt a full pound of boost, but you are getting a measurable amount over atmospheric pressure and vacuum of the engine.
Combine your forced air charge with cool air and low DA and VOILA!! Instant trap speed from nature
Example of our front grille:
Take your hand palm forward and hand vertical, and place it out of your window like every person has done as a kid
Note the force of wind from 10mph, 20mph,30mph etc up to let's say 110. You're crazy to think that you can't direct that into the intake and provide the minute bit of positive pressure we speak of?
A well designed intake and filter system can provide POSITIVE pressure into an engine and has done so for decades. You may not get quitt a full pound of boost, but you are getting a measurable amount over atmospheric pressure and vacuum of the engine.
Combine your forced air charge with cool air and low DA and VOILA!! Instant trap speed from nature
Example of our front grille:
Take your hand palm forward and hand vertical, and place it out of your window like every person has done as a kid
Note the force of wind from 10mph, 20mph,30mph etc up to let's say 110. You're crazy to think that you can't direct that into the intake and provide the minute bit of positive pressure we speak of?
raymondwebb
Full Access Member
I did the same thing as trainman with my volant I get air from the hood and the left side of my grill via a BMW brake duct and some 4inch pipe that runs into the volant air box and the results are great....more air equals more power erbody knows that
SrtBrad
Michel Productions
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Another misunderstood fact with our trucks is that the scoop is not used for a "Ram Air" effect at all. The scoop was designed to ventilate the heat out of our engine bays.
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