Its an airbox from an 05 G35 Coupe. Someone help me out please!

 

I would think so....

 

Yep, that's a velocity stack.

 

 

Yeap, my 35th Anniversary has the very same stack in the air cleaner box.

 

Velocity stacks are kinda weird. Even though they speed up the air, they dont increase the mass air flow. My guess is their only real benafit is decreasing turbulence.
And yes, thats a velocity stack

 

All the rev-up engines have them (in the sarcastic tone of "all the cool kids have them")

 

How does that torque feel?

Ha ha haaaaaaa

 

Here is why they work.

You know how when a waterfall is flowing slowly and the water is trickling over the edge it hugs the cliffs. Now imagine what it looks like when it starts rushing, the water shoots out past the cliff as it arches downward. The harder it flows the bigger the radius as it falls down the mountain.

Now imagine the waterfall is a big circle and water is coming fast from all sides to head down the hole in the center. It will still want to shoot out from the sides and curve down but now it's running into water coming from the other direction. Soon the water will back up and have to wait to flow down the hole because the arch is actually causing a restriction at the mouth of this big hole.

To fix this, add a radius at the top of the hole, so the water has room to arch as it falls and the water will hug the walls once again. when this happens, it does not need to take up room in the hole and now you don't have that restriction.

The same applies for air only is it coming in from the top as well as the sides, so there is even more reason to help keep it flowing smoothly. By not having a velocity stack you are basically adding a choke at the inlet.

Chris

 

this is just like that elementary school experiment where you tape two 1 liter soda bottles together with a washer in the middle and create a vortex

 

True velocity stacks work on the principal of resonance. This has none of that. It looks like a smoother transition to get air where it need to go.

V-stacks work on the principle of resonance compressing the air, and the length of the V-stack determines where and when the expra pressure comes in to play in the power curve. A true velocity stac is 1 stack for each runner, not 1 stack at the opening of an intake behind a filter.

Here are some examples and reading.

http://www.land-and-sea.com/marine/velocity_stacks.htm
http://www.gravesport.com/cgi-bin/sh...on&key=AB__012
http://www.autozone.com/servlet/UiBr...3d8004e98f.jsp (look up velocity stack)
http://www.hydrostream.org/TechTalk/...tackTheory.htm

 

What your atlking about id the venturi effect not the principle of stacking.

http://en.wikipedia.org/wiki/Venturi_effect

Not purposley busting your ***** or any thing. It would just be a shame for some one to bring in, "the turbonator does this"... or the (insert crapy intake mod here) does this.

True the venturi effect does add velocity, but does not increas volume due to the longer distance of the swirling motion the air has to take. The stacking creats pressure which inturn increase over all quantity of air in the intake.

 

So can our intake box be modified for more gain?

 

I wouldn't be so sure. The tuned effect would still work on a single intake tube as well as on multiple tubes. "A true vecocity stack is one for each runner"? That is the most common form seen on race motors where the realities of air filters, noise control, etc. are unimportant. But the Nissan airbox is a true velocity stack that performs all of the functions noted in scientific descriptions of the principle.

 

A tuned runner the length of the intake is way out of the band for our cars. This item in question acts more on the venturi effect straightininig the turbulent air after it exits the filter. This way the air swirls and flows down the intake as oppoesed to turbulent air that oscilates arround the diameter and is eventualy pushed down the intake, like blowing smoke in a pipe. Yes this item does increase the velocity but does not stack the air, which creates a pressure wave.

 

The bottomline is.......................................................... Are there any powergains or milage improvements from this?????

 

Based upon the reading I have done on this subject, The velocity stack, per se, is not the important factor in the "ramming pipe" effect that you are mentioning. Not to get too technical, but a tuned length of inlet pipe can inhance the output of the engine. The reasons why it works are exactly the same as why a tuned length of exhaust pipe works, refected waves that move both directions in the pipe, at the speed of sound. Tuning the intake tract of a street car certainly can work, and certainly was carefully designed by the engineers ay Nissan. As a matter of fact, I have a book that fully explains the tuning effect, and gives the intake pipe length for optimum ram effect at a variety of R.P.M.

3000 rpm 31"
4000 rpm 23"
5000 rpm 18.5"
6000 rpm 15.5"
7000 rpm 13.5"
8000 rpm 11.5"
9000 rpm 10.5

The bell mouth( "velocity stack") we are discussing does not produce the tuned effect. The ram effect of tuned intake is solely created by the length ot the intake (and exhaust) piping.


10000 rpm 9.5"

 

I was speaking of the velocity stack runners, not the intake. Yes, this is exactly how this works is on the ramming of air. The bell opening just smooths the flow of air into the intake.

For these intakes there are too many bends ad desruptions to effectively create a stacking effect.

 

Bottom line yes you will get minute power diffrences and milage gains from this, say compared to a hole in the wall (totally flat). To show how minute the gais are surpassed by relocating the intake for a colder charge of air. At this point you just wusing the intake as a straw (CAI's and intake kits)

 

287 HP Air Box Velocity Stack:


REV-UP Air Box Velocity Stack: