Since i've seen a couple of posts related to ram air systems and such, I figure I would let everyone in a little secret that no one seems to know.

http://www.paladinmicro.com/documents/RamAirMyth.pdf

 

............and now you know why I didn't make my scooped hood functional.

 

well, the benefit you could of had was lowered underhood temps, these cars drastically need something.

 

On my car, the hight of the scoops nostrils sit below the layer of "dead air" that surrounds the car as it moves thru the atmosphere. For a scoop to really have any real "Air catching ability" (I won't use the term "Ram effect") it needs to be positioned above the layer of "dead air" which flows about an inch or two above the bodys surface area. Or be positioned as far forward as possible (which would then act like a wide open window in a hurricane).
For a more effective scoop design to actually grab enough cool outside air to create any measurable under hood cooling, I'd suggest using the scoops off of the following cars.
69/70 Boss 429 Mustang
69 Hemi Dart/Cuda
70 Firebird Formula
70 AAR Challenger
69 Rambler Scrambler
65 Comet A/FX
69 Hurst Olds 442
Just to name a few.

 

Thanks for that. Made interesting reading and having studied Fluid Mechanics at University and Work I can understand the theory.

So I'll stick to my guns and leave the induction stock.
Mercedes and many other engine designers know better than somebody trying to sell an air filter which only serves the purpose of adding a bit of bling to the engine bay.

 

Well that starts my day.

The definition of ram may make a difference to this guy but does forward facing inlets make a power gain, yess and Helll yes.

I have had a 1962 chevy 153 cid that would only go about 78 mph at fort Hood in texas. While in the army I started PLAYING and used soda cans for tubing and fashioned a cold inlet that ran from the carb airfilter to the grill. I even had dual inlet pipes ( soda can tubing and duct tape - had no money and more time than anything else ). They looked like the devil horns of today.......

Anyway with the tubing ( additional friction) I was able to see a power gain that put it over 85 mph when it was wound out. THat was a flat road for ever winding it out and a significant power change, 7 mph on top.

So I d say CRAPPE to this article, its like religion, there are many and they all point in different directions.

Fact we are not super sonic, but cold air and the mild boost at speed will blow air into the engine improving horsepower. I have measured several inches of water column boost of ram if you will at the grill of my car at speeds at 55 mph!!!!!!. If it is free why not use it and its colder.

I dissagree with the article, there was no testing and only conjecture.

Check out wind tunnel testing for NASCAR, NHRA, and other outo interests and note that they rely on lower drag (air friction at 100 mph and up) to perform. They also design air inlets to the engine for cooling and intake to the engine to maximize horse power. Car manufactures also want to reduce the wind loading or drag that is substantial even at 55 mph. Air is thick, try standing near traffic of watch 750,000 pounds of protein and aluminum glide over your head at only 200mph.

Naw, the forward facing inlets will gain significant and MEASURABLE power gains. That is why I had to prove to ROB at needswings that the second inlet would allow MORE air into the supercharger due to less friction and greater inlet air flow. That was CAI before, the second pipe allowed more of the air pressure from the front of the car to enter the s/c - - - READ DENSER air charge. Ask a Dual CAI car owner how much he fells in the way of a gain, AKA buttometer.

QUESTION AUTHORITY and the CHURCH. WOODY.

ANd then test - test - test to be sure,

 

Well put waldig.





I looked at this guys article and believe there are entirely too many people (including racing) who have noticed gains to simply dismiss the use because of an article by someone whose credentials in this area are unknown outside of the fact his critique is on a number of auto web sites.

 

Right on Woody!!! - Thanks for your post...

When I first saw this thread and read the article, I thought, what racing team employ's this guy? What a crack pot.

I could just see a funny car staging with his scoop pointed backwards so the driver could watch his butterfly valves... and still pull the same ET...

Many of the scientists who laid the footwork for fluid velocity lived a long, long, long time ago - totally in the face of what the author has stated.

I do agree that terms like "Ram-Air" and "Cold-Air" can be a bit misleading if you only looked in the pure terms of supersonic ram jets, or air refridgeration......

May our CAI and Ram intakes live on....

 

when i opened this thd. and started to read,, i stoped closed it to see if i was on the (JOKE thd,) went back read the art. and yes i must be reading a joke, i have been racing for 50 years now , if you decited that this wasn't a joke then try this,, remove the plastic tubes going to your factory intake,, go for a hour drive,,, make sure you have a full tank of gas because without the factory ram air your gas milage will go down so will the power.. now if you can add a needswings intake, this will ram more air into the throttle body which will give you more power and better gas milage. do you think that K & N , air force,injen, needswings could advertise a increase in hp and miliage if it wasn't there. now go back read it again and join me in a big laugh.. jim

 

Just so my post isn't misunderstood, I was only pointing out why I left my hood scoop nonfunctional, because it's not "tall" enough to offer any "Ram AIR" capabilities. Something I've posted several times in the past, when challenged.
Like BrianBrave, after reading that article, the first image that popped into my head was all the Top Fuel Dragsters, with their forward facing scoops, and their butterflys wide open not enjoying any performance increase.
I do question how much actual "Ram" effect one gets from NeedsWings intake when the tubing makes a 90 degree bend directly in front of the radiator into a giant K&N airfilter, that's facing sideways.
I think the 1/2 second quicker 1/4 mile ET's (that are enjoyed by the NA Crossfires using the NeedsWings system) comes form the larger volume, and smoother flowing mass of cool air being introduced into the intake, rather than any actual "Ram" effect. But that's just my opinion.
I think its been pointed out repeatedly how restrictive the stock intake housing is on our cars, even the two "corrugated" tubes that lead up to the radiator core support disrupts the smooth flow of air causing turbulance.
The 1996 Viper came with this same type of corrugated style intake tubes, and it was rated at 450 HP. But when the GTSR appeared, the corrugated tubing was replaced with two smooth silcone tubes and the H.P. went up to 460, with no other modifications.

 

look at the grille,,, it is set up to let air in but not out,, there ia a presure build up behind the grille ,, most is forced through the radiator. and some is forced into the,needswings intake.
filters,,, look into a turbo intercooleror ,leave it open to the air,, or behind a grille?? Oh what about xray having his grille blown off at 100 mph the pressure behind it (bottom clips were not cliped) blew it out and away it went..if it didnot have pressure behind it then it should stay on like a sheet of paper over your grille when driving . jim

 

Interesting Jim, I never heard that about Xrays grill coming out.
So if I understand you correctly, you're saying there's a "pocket" of built up air that gets trapped behind the grill, but in front of the radiator, and that gets "forced" into the airfilter?
Never thought about that happening....thanks.

 

When you say RAM air I understand it as an increase in pressure, CAI's provide more and cooler air they are not providing air at an increased pressure. The air filter will have a lower pressure on the engine side than in front anyway.
Functional air scoops provide more available air so that there is enough for combustion.
NA's benefit having more air to mix closer to atmospheric pressure, the lack of air will produce less pressure inside the intake manifold and therefore less air ingested into the engine. SC's benefit by having enough or more than enough air to compress and therefore do not starve.
The more air than can get into a NA's intake means that the pressure inside the manifold will rise closer to the ambient pressure, but never get too close to exceeding it. True RAM air would exceed the ambient air pressure inside the manifold, just like a SC.
Sticking your hand out of a car window you feel the air hitting it and pushing it back, but some of that force is the lower pressure behind your hand pulling it back, this is off course similar to the lift that a planes wing generates to keep the plane up in the air.
But please keep your hands inside the vehicle at all times, especially at the lion safari park.

 

Yep, I'm going with Woody on this one.

Whether compressed air gets to the throttle body on not, the induced higher pressure at the inlet has to help overcome the fluid friction of the inlet tubing.

Even the 3.0" CAI tubes have friction on the walls. That is resistance. That is turbulence. That spells lower air pressure, ie vacuum; ie lower density air at the TB. Vacuum creates turbulence because of eddys. Added pressure at the head reduces vacuum induced turbulence. There is higher pressure in front of the radiator and that is absolutely ram air.

The piston engine is nothing more than a compressor with a spark plug. It takes HP to draw the air into the cylinder as the piston moves away from the head. Any resistance to that movement uses HP. Lower that resistance, cancel that loss. This is why it takes a 10 HP compressor to do a 5 HP mechanical movement.

There is also higher pressure at the base of the windscreen although less volume. This is particularly true with the higher aspect windscreens of cars from the fifties and sixties. Early sixties Chevy had a kit for it. It improved performance on carburated cars. I put one on my 56 Pontiac and had to open the highspeed fuel jets to keep the mixture rich. That suggests more available air.
Buttmeter said I got more HP at the higher speeds.

So did my street racing tickets.

It also made my wipers feeble.

roadster with a stick

 

yes, with a properly designed scoop, you will have higher inlet pressures, think about that funny car, large scoop, large frontal area, and it narrows down at the end, that causes higher pressures.

A properly designed system will have a "ram air" effect, but its nothing like some of these people think or what companies advertise

 

Vacuum? Lower air pressure is not a vacuum. Vacuum cleaners do not make a vacuum, they pull air away and the surrounding air rushes in to keep things balanced.
Slow and fast moving air is like slow and fast moving water. You can wade across a slow flowing stream 6" deep, try wading across that 6" stream when the water is flowing much faster. Its the force of the water than bowls you over, the water pressure has not changed.
To increase air pressure you have to concentrate more of it into a given volume. The amount of air caught in front of a radiator has to be compressed to get any rise in pressure, the air that is outside the grille cannot do it as it is not there at a sufficient density to act as a ram. The draft behind the grille is just that, a strong draft and it just wants to settle back to the state the surrounding air is in.
Air rushes into a cylinder to fill a void, it does takes power to push more air than nature can provide into the cylinder, and that power would be the SC in this case.

 

Why is air entering you engine? Because the piston went down in the cylinder and caused a "vacuum" which is replaced by ambient air.
Vacuum by definiton does not mean an abscence of air, just a "lower than ambient" pressure. Partial Vacuum is still genericaly referred to as Vacuum.

I deal in vacuum enginering all day and have a vacuum related patent. In any Na engine, what's going on in your intake is vacuum. That's how the vacuum that operates vacuum systems on older cars worked. Using the Vacuum created in the manifold to operate the wipers, or the locks, or the baffles and gates in your HVAC systems. Also, it was the Vacuum inside the carburator that made the venturis operate.

And the dial on the gauge many cars have that says, "Vacuum"


In a fuel injected engine, it'a all about getting "air" to the cylinders. Period.
Got it?


roadster with a stick

 

 

Definition - Vacuum is the absence of matter.
Nature abhors a vacuum or any differential pressures that it can balance it if at all possible. The air/fuel mix enters the cylinder in response to the differing pressures inside the cylinder and the manifold. There would never be a true vacuum inside the cylinder, just a substantial difference in pressure between it and the manifold.
True vacuums are impossible to achieve, the closest to it that we can get is scattered air (gas) molecules floating around in a near vacuum. The last stage to produce this near vacuum, after physically pumping out most of the air is done using an oil fountain, the air molecules that remain hit the oil and stick to it, you cannot get all the air so some remains in this near vacuum.
This near vacuum is what Cd's are aluminized in to give them the mirrored look we see. The aluminum is vaporized in this near vacuum and settles on the plastic surface evenly in a very thin layer (55nm). It is some thirty odd years since I did this so the details are a little sketchy in my head.
No vacuums are associated with IC engines. Vacuum lines are lines with less air pressure in them, the less pressure there is in them the more force they can have exerted against them.
Ideally they would get to zero (nowhere near it actually) and thus allow 14 psi (approximate atmospheric pressure at sea level) to work against the diaphragms etc.

 

Theory is one thing. Practical applications is another. For instance we know in theory that fusion is better than fission but a practical use of fusion evades us.
Still we pontificate about it as the clean energy source that will save us from using fossil fuel to poison Mother Earth

This acedemic argument is no different.

Has it occurred to anyone that before people, specifically racers, spent time and money putting ram scoops on their engines somebody stuck a pitot tube out the window to see what pressures could be created by the vehicle's movement thru the air?

And then did the requisite engineering to see if that "pressure " could be utilized in the components of the engine to create more power.

I will put together some components off the shelf here this week and test my presumptions in Cathy's SRT this weekend when Shark067 and I go to retrieve an Aeroblue SRT in Tyler Texas.

roadster with a stick