Exhaust+CAI=Results? I've got an opinion.

Think I would agree with the first point. Increased flow volume would not put more air mass into a given space at a given pressure. The amount of air that can fit inside a cylinder remains the same at a given pressure. So opening the intake to allow more volume should have no effect, provided the stock system is filling the cylinder adequately. Think of it like filling a cup with water. Fill it first by trickling water through a straw. Now fill it by turning on your garden hose at full blast. Same amount of water fits into the cup.

Now if you put a compressor on there, such as a turbo or super, you are increasing the pressure of the air. Therefore a given volume of space can hold more mass of air. As far as ram air goes this should help as well. Air pressure = static pressure + dynamic pressure. With a good ram system you are increasing overall air pressure so should be able to increase the mass of air that fits into a cylinder.

I learned all about this in my aerodynamics class in Navy flight school. Its been a while though so some of my knowledge may be a little jumbled. I remember there being something profound about the effects of ram air at subsonic speeds but can't remember what it was. If I ever dig up my books I will post about that as well as correct myself if I was wrong about any of the other stuff.

 

I have a dyno graph of my girl's XR. TRD CAI, NST pulleys. Very similar to that graph. I will post it up shortly.

 

Betcha she's a monster now - eh?

 

Oh look an HAI ( Hot Air Intake) Gauranteed to reduce HP by 12-18HP, but sure sounds like you know what you're doing when you pin it....

 

She moves pretty good.

TRD CAI, NST Pulleys.



Not to bad for some pulleys and a filter.

 

I'm stirring the pot work with me.

 

that graph as alot of short cycle noise in the torque curves

 

As I said in the other post, air viscosity does not change with pressure. So the air flow is not "easier". The only way to get more mass is with more flow OR change the pressure of the gas. Assuming the temperature stays the same.

Let's stay with the "CAI" portion of the intake tract for a while. We can discuss forced induction later. Read the intake manifold spacer thread for more information on the after the throttle body portion of the intake.

I guess my math was acceptable, as I expected comments otherwise. So let's use those results to here. 141.5 cfm, 48 ft/s at MAF, for wide open throttle at 3000rpm.
So if this was at sea level air density is 0.075 lb/cf, so 10.6 lb/m of airintake. ( http://www.engineeringtoolbox.com/air-altitude-density-volume-d_195.html ) If it was at 5000 ft elevation then 8.8 lb/m. Pressure matters.
So how to change the pressure of the air in the "CAI". Look at the earlier linked study; http://www.fueleconomy.gov/feg/pdfs/air_filter_effects_02_26_2009.pdf . It notes pressure losses over different air flters. So intake side of filter has a higher pressure than the outlet side.
Ducting turns and irregular surfaces also cause flow restrictions. Minor, but they all add up.
Then there's Bernoulli. He told us that as stream velocity increased, pressure decreased. So the 48 ft/s flowrate we calculated would have lowered the pressure in the stream.
What if we reduced the length and removed some the elbows from the intake duct?
What if we increased the diameter of the intake tract? The velocity would go down with the same flowrate. Lowering the velocity would allow a higher pressure air.
What about a low restriction filter?

So, would you want the cylinder to fill through a straw or a 5# coffee can?

 

I'm just going to blanket comment all of this with- we have proven again and again that CAI's do nothing or next to nothing. The cost to benefit ratio just doesn't cut it. Did we already post up that intake fan thing? The Tornado or whatev?

Oh, and braaaap.

 

Doesn't matter if you math is correct, it isn't convincing of anything. Simple matter is the stock intake on the 2.7L isn't a straw and is only a slight restriction. 4.9# can vs 5# My point is yes at higher altitude air is thinner and causes even less mass flow so less impact on intake. None of your math changes that. Viscosity doesn't matter in a vacuum eh?

And no I'm not confusing ram induction with restriction before the throttle body, just commented on our mention of tuned port.

 

Wait, if you add OnStar.....

More derp??

 

Yes ram air. Our aircraft use huge ram scoops to deliver more air to the engine. Of course we also have turbine engines with a 3 stage compressor as well allowing 1100 shaft horses. I'll try to dig up my aero books and post what it says about ram air. I think it had to do with compressibility and sub vs supersonic speeds. Of course its also directed toward aircraft but the principles should be the same.

 

I would think that a turbine engine and an internal combustion engine are totaly different. like apples to rocks different.

 

Talking about the principles of ram air, not the internal workings of the engine. But thanks for the vote of confidence

 

Pro Drag cars, N/A, make up to 3 psi "boost" due to ram air. Once they surpass a specific velocity.

 

yes because our trucks approach near Sonic speeds.....

 

Ohya, my Tacoma will do 140-165MPH in a quarter too....

 

Well I think this clears things up. Ha ha...I guess my memory failed me. I thought there was more of a connection to a reciprocating engine. I think the line about mass and pressure of inlet air may apply however. Oh well go ahead and laugh at me. I still have a kick ass job regardless!