Air velocity is not pressure. The air velocity to which you refered is "in the nozzle" It has no reason to have an increase in velocity unless there is a difference in pressure between the one end of the nozzle and the other.

If a pipe is forced thru a gas and the gas in the nozzle has a velocity increase, it must be the result of different air pressures in the leading end of the pipe verses the exiting end.

The venturi diagram above illustrates this fluidic function.

As to sources, if you Google Ram Air you will get some technical and a ton of retail sellers hawking their science. I may have some technical textbooks in the engineering section of my own reference library. But I only remember them to have a chapter or reference to the science, not engineering tables for application.
Tonite, I'm packing for my trip to Tyler TX to retrieve an SRT for the CAA raffle. Won't be back until Saturday.

I will be doing the mythbusters on the way down.

BTW the picture shows a bad way to do it. Corrugated pipe, bad. Orfice has no accumulator horn. Airflow will not be laminar (smooth) or pressurized.


roadster with a stick

 

The scientific population are holding their collective breaths waiting for the latest breakthrough in this field of study. All the computers and all the delicate lab work is going to be for naught as Franc eclipses their work simply by poking a hose out of a car window.

I'm going to start a new thread on the possibilities of turning lead into gold - Alchemy 101. When I get the answer I'll buy all of the CAA SRT- 6 lottery tickets with what used to be my fishing sinkers.
.... ad infinitum

 

LOL my friend LOL

Look, we are not testing drag coefficients here. And besides, I only have 192.5 HP at the wheel. So my nose, delicate and beautiful sensory instrument that it is, stays well inside.

3/16" dia pitot tube 12" out in front of the grill. Then 15 feet of 3/8 dia hose back to the meter. Got 3" of water @ 60 MPH and 5" of water @ 80 MPH. Then the duct tape came loose and my needle did a jig.

I got 1" just driving across the parking lot in 2nd. That surprised me.

Real tests tomorrow.
3/16" pitot inside grill, pitot outside grill
1.0" pitot inside, and outside
3.0" dia PVC with a 4.0" long horn in free air stream
3.0" dia PVC with a 24.0" long horn in free air stream
3.0" dia PVC with a 4.0" long horn at top of windshield where air is high pressure.

My inH2O meter is calibrated to 15 inches.

I do not have a properly calibrated flow measuring device but will use a medical flowmeter.

We may or may not get to Texas Thursday nite but by golly I will have collected a pile of useless data with which we can continue irritating the PHD's (real or imagined) on the Forum.


roadster with a stick

BTW, I liked your dancing old fart better

 

Have a safe trip Franc. No dings in my SRT.

 

Kell, Shark067, will be driving the SRT.

I will be the roadster with a stick pedaling as fast as I can behind him.


franc

 

What was the temperature of the air ? I'd also like to see what the stock airbox would do as a baseline.

 

60 F
Barometer at 30.12

franc

 

The two of you with no adult supervision....oh the thought of it....

Come back safe and don't pollute MY SRT.

 

Had a lot of fun today with the meter and all tghe tubing. One piece looked like a bong and received more than a curious glance from the Arkansass Highway patrol.

I will have other wconclusions when I get back home but one thing is clear. Ram air is not a solution for adding reliable performance or HP.

That said. I made one change in tghetest equippment. The PVC collector horns and tubing are 4.0" insteadof three.

All tests were taken at 80 MPH except for a series of Pitot samplings at 60 thru 100 MPH
PITOT TUBE 10.0 " IN FRONT OF GRILL
60 MPH = 3.2 inches of water
75 MPH = 5.2 "
80 MPH = 5.5 "
90 MPH = 7.5 "
100MPH = 9.1 "


80 MPH tests
Pitot tube 10'0" in front of grill = 5.5"
Pitot tube inside grill /rad cavity= 2.0"
4.0" short horn (4.0") @ windshield = 6" to 15" turbulent
4.0" long horn (24.0") @ windshield = 7" to 15" turbulent
4.0" short horn in clear air = 4.5"
4.0" long horn in clear air = 6.0"

1.0" opening with gradual taper clear air = 5.5"
1.0" opening with gradual taper windshield head = 6.0" to 8.0" Turbulent

5.0" to 6.0" of boost might not be supercharger power but many turbos work in that range. Maybe just maybe........this could work.


But?????
Something we noticed, that I had not considered, as we approached vehicles in front of us the pressure dropped dramitically. So just when you need a boost for passing, you are lame until you get clear air.

Second thing we noticed. If you are passing a truck, you get turbulence the whole time you are passing the rig.

Turbulence will rob HP and without some baffle control you lose any boost you might have thought you gained.

Finally, holding the intake horns in clear air exhibited a force that I also had not considered. Any scoop or intake horn must be properly designed and placed so as not to increase drag. At 90, 100 MPH it was all I could do to hold the 4.0" pipe in the airstream. This suggests that any power gains could be cancelled by increased drag of the collector.

No conclusions tonite. I will wait until I get home and have some time.
Except this, ram air works, I just don't think, in an automotive application, it is useful.

Onehundred 80, tell the Labs they can go back to work.


roadster with a stick

 

What turbo is designed to make 0.216 psi lol?

 

Exactly.
But Ram has one definite advantage in that it can channel air, increase it's availability to the engine. This has to improve effeciency and, to a degree, performance.

The best Ram may be able to do is reduce vacuum, or more correctly low pressure in the intake and manifold. This can be significant, especialy at higher RPMs.

But the design must not increase drag or induce turbulence.

roadster with a stick.

 

backpedal.jpg

This thread was a fun read.

 

Yeah, this thread fizzled out like a damp cracker on the fourth of July.

 

Banks Power | Air Density Testing

 

Here's my take in a nutshell... Ram air is bogus lol. The air filter will slow the air down laminarize the flow, regardless of what the air around it is doing. I was driving around yesterday and by car felt like it needed a tune-up. It was bucking, stumbling, and all together running like a turd. I pulled over and noticed my air filter fell off. I was getting mad ram airs, yo. (I know, I know, the MAF sensor was bugging out) but as almost every article said.. an engine will benefit from static pressure, not dynamic.. velocity through the intake tube is not ideal.
That banks article confirmed my suspicions.. ram air will provide no pressure increase.. in fact, every intake setup has a pressure loss associated with it. But a good intake system will "save pressure from being lost".. My idea was that chaging the inlet location will draw cooler, denser air.. not make a machine out of the intake tube .... there is no work being done on the air, just less resistance through its path of flow, with a smooth path of flow to promote laminar flow.

 

Downward, I got excited when I saw a word that I did not know. Thinking I am going to learn something new today. I looked it up in the dictionary and could not find it. Maybe it was just a spelling mistake..... laminarize. I am not trying to be smart here. I really do like learning new things. What does laminarize mean? Thanks

Edit - I found lots of articles via google that use the term laminarize or laminarization. They all seem to be related to air flow, but I did not see any of them that explain what it is. I guess a technical term that you would know if you were in the field of flow dynamics? Ok, I am more curious now. Thanks again.

Bob

 

Laminar flow is smooth flow, i.e. the opposite of tubulent flow.

The -ize suffix means: "to act in a certain way; to treat in a certain way; to make into; to treat with; to do; to make; to cause".

So he's saying that the air filter reduces the turbulence of the incoming air.

 

Sweet.... thanks Thumper. I must admit, I am a bit of a wordsmith. Not sure if I will ever be able to use it in conversation, but that baby is now stored in case the opportunity presents itself. LOL

 

This pretty much restates what Thumper said. But I wanted to point out that laminar flow is directional, meaning that all of the particles are flowing in parallel and not disturbing the flow of the others. In turbulence, the particles are chaotically bouncing around. Laminar flow would be like a whole bunch of cars, all going the same speed and all staying in their lanes on the highway. It's efficient and no one is messing anyone else up. Compare that to actual highway driving where everyone is going at different speeds, cutting each other off, changing lanes for no reason, etc. Chaos vs. order.

That's one reason why some MAF sensors have a honeycomb in front of them. This helps to laminarize the air flow so the sensor can get a more stable reading.

I think Woody was playing with a honeycombed cold air intake or intake manifold. I don't know what his results were.

 

Excellent explanation Tom. I remeber reading some time back in an older post where NeedsWings had actually tested the NW CAI without the filter. They found that it hurt the performance. I did not understand why when I read the post, but now it makes sense. I love the diversity of the members of this forum. I am always learning something new.