They all had them. Maybe smokey came up with the idea, but it was standard on all the Z11 cars, even Ronnie Sox's....
http://www.streetlegaltv.com/news/muscle-cars-you-should-know-63-chevrolet-z11-impala-427/

The auto manufacturers sure have wasted a lot of money with hood scoops and ram air setups over the years.

ok then. Red line is normal atmospheric pressure.where's the boost from ram air?

We have a different benchmark I guess for what makes a fact vs a myth then. All I see is colored graphs.

So, ram air works, eh?

In that sense, you're sure right buddy!

Exactly, a couple of graphs with no explanation of what they are does not prove or disprove anything.

If you want to see ram air in action then call a Pro Stock team and ask them for a pressure reading from the air box during a 1/4 mile run. Or call up a NASCAR team and ask them the same info. Or to make it simple call Dave Braswell and ask him how much air pressure a Pro Stock carb sees in the lights and how it changes the AF ratio.

if you have contactinfo i'd call! i'd be curious to see exactly whats going on. Thanks good Sir.

Depending on scoop inlet area, as soon as the vehicle sees a specific velocity that creates a flow volume greater than the engines need at its specific RPM you will, from that point and accelerating further, have a positive pressure situation.

What is the bottom value (X axis) and why are the graphs so different?

Basically what this is saying is that +.34 Psi @ 14.21 psi = + 17hp difference IN FAVOR of ram air. Which is good. However air is incompressible at speeds below 230mph IE: 14.7psi @ sea level + xx value.

So the ram air does work at bringing the PSI close to atmospheric pressure of 14.7, but will not cross that threshold until ground or airspeed reaches at least 230mph.

So myth confirmed, to a point. My apologies, as I should have said ram air to create boost, as boost is defined as 14.7psi + xx.

Exactly, you don't necessarily need boost to create more power, more flow will do that. However there are plenty of MAP readings out there showing above and below atmospheric pressure depending of configuration of the inlet. Do you think a knowledgeable racer would sacrifice aerodynamics of a protruding hood scoop if it slowed the car down? I think not. Do you think none of these teams test?
Doug

BS

Thats it? Then what's your insight? Cause BS is the answer of a prepubescent teen.

Something is wrong with your basic assumption that air is incompressible at speeds below 230mph. That statement is false, air is compressible at any speed. So that original statement needs to be run down and understood. I think it is causing all of your confusion.

It is vey easy to hook up a pressure gauge in an air box and drive down the road and you'll see positive pressure well before 230 mph. So someone just made a basic error when they wrote that statement.

So, who said it created positive manifold pressure at common race speeds?

If it reduces the amount of vacuum in an intake then it has been successful. It does not require pressures above barometric.

Air inlets of different shapes and sizes will create different pressures. Combine that with different air demands of different engine/chassis/speed combos and you're all over the board.


As for JCC, don't try to make him think something he doesn't want to think. He has his own little ways of fighting for his preconceived notions. That's why I have him on ignore.

Agree with this statement, although it's been a long time since I got my ME degree. To the OP, please identify the source of your info? Seems to me there may be some confusion there since air absolutely is compressible, but in calculating line losses in fluid flow it was acceptable to treat air as "incompressible" within a small range. If the pressure drop (hence the change in density/volume) was too great you would you would have to break the system into smaller segments to do the calculations.

Of course, that was back in the day when YOU actually did the calculations, and not just feed info into a computer that spits out a number.

Just hook up a manometer to an air box and you'll see that it generates positive pressure even at highway speeds. That is all the proof that you need.

From your source:

"the Mach number (the ratio of the speed of the flow to the speed of sound) must be greater than about 0.3 (since the density change is greater than 5% in that case) before significant compressibility occurs."

Key word: significant. It does not say it is not compressible, just not significant. So what everyone has been saying is correct, and there absolutely is a pressure change and a potential performance gain possible from ram air.