CAI indepth.....

[ticopowell]

It was the same diameter right next to the MAF, but it did remove other restrictions like in the fender, and it was a smoother path between the filter and the throttle body. Here is a good example of what I am saying about the CAI's I have dealt with. both were exactly this same idea.
the only think that I can think of that would affect airflow is that the air maybe be relatively faster or slower in that part of the tube versus what the stock tube would read. since this can affect that area without the MAF reading it (because like someone said the MAF covers only about 14% of the circle of air in question), that is why any adjustments would need to be made.

[Longshot270]

Originally Posted by ticopowell

It was the same diameter right next to the MAF, but it did remove other restrictions like in the fender, and it was a smoother path between the filter and the throttle body. Here is a good example of what I am saying about the CAI's I have dealt with. both were exactly this same idea.
the only think that I can think of that would affect airflow is that the air maybe be relatively faster or slower in that part of the tube versus what the stock tube would read. since this can affect that area without the MAF reading it (because like someone said the MAF covers only about 14% of the circle of air in question), that is why any adjustments would need to be made.

Well if the inside diameter of the housing is the exact same as the stock housing then you should be fine. The pipe after it doesn't matter and the open filter before it only affects performance through air temps. The issue is not that the MAF only covers 14% of the cross section, the issue is the air speed through the cross section. You are not measuring the actual mass of air, you are measuring a part of the cross section to determine the rate at which air enters. From there you can calculate the overall rate and then the mass of air passing through. You dont measure flow rates of a river by channelling it into a big cup. You find an area that has uniform flow, measure the rate there and the rate at which water is moving through the area. Increasing pipe diameter with the same air consumption rates causes the airspeed to lower and tell the computer to fuel less.

We are dealing with vacuum rather than pressure so the concepts are much simpler.

[hampsterzone]

I'm glad that I got the down low on everything from just about everyone. Makes since and I have learned a lot. I love being the first domino, Haha.

[Skip_1074]

Originally Posted by Longshot270

That is a good observation. One thing that is recommended for people with CAIs are the canned tow tunes. They are written with a richer A/F ratio and it helps counter act the lean effects.

I bolded the part that I usually find important. Air is a fluid and fluid dynamics is a tricky subject.

I usually go fishing to waste time...but whatever floats your boat.

When I read the OP, the combination of the Edge and CAI caught my eye while I was still on the first sentence, and I was actually surprised that nobody else mentioned it.

I understand fluid dynamics, but not to the point that I can confidently speak on it. You are definitely right about air being a fluid and it being tricky. I have searched a little today and I can't seem to find an article that I read on Banks Power, specifically addressing air being a fluid, but here a chunk borrowed from one of their articles:

Courtesy of BANKS POWER:

In the confines of a stock motorhome or truck, your gas or diesel engine’s inherent power is limited by factory restrictions in the intake and exhaust. With your engine starved for air, a tremendous amount of power traveling through the power-train is unnecessarily wasted before it gets to where it matters—your vehicle’s rear wheels. Airflow restrictions make poor engine efficiency, which soaks up fuel, runs a hot exhaust, compromises performance and shortens engine life.



How airflow restrictions waste power

* Intake restrictions cause engine to labor (“pumping losses”)
* Exhaust backpressure generates a tremendous engine heat-load
* Power is robbed from the crankshaft to expel exhaust
* Cooling fan runs often, wasting power and making the cab noisy
* Hot, overworked lubricants degrade faster and increase friction
* Gasoline-vehicle makers mask poor-airflow problems (eg. detonation) with overly-rich fuel
* Excess fuel is wasted, worsening mileage and emissions
* Inadequate airflow chokes engine’s potential

Think of an engine as an air pump that produces power. To run it, fuel is needed. In a typical stock vehicle, a gasoline engine produces only about 250 horsepower for every 1,000-horsepower’s worth of fuel put in. Diesel engines are more efficient—they put out about 320 horsepower for every 1000 in, only wasting 68%—still leaving lots of room for improvement!

Hampsterzone, you discussed backpressure in one of your earlier posts. As you notice, backpressure actually creates heat excess heat in the engine acting as a "parasitic loss" in power.

As for the time wasting that I did this morning, I was trying to do some calculations in regards to engine CFM airflow requirements in comparison to the ability of air systems to move them, but unfortunately I was unable to find the capability of the stock air system. But just for and , the max CFM flow of the 5.4L 3V engine at 5500 RPM is 628 based on the calculator that I have.

I would have gone fishing, except for a few things...its was only about 3:30am when I started the post, around 5:00am when I finished it and I'm pretty sure you can't get your line wet until first light. It was about 25 degrees outside and the closest place to go fishing is a GOOD hour plus away. The only reason that I was still up was my daughter had late start at school and I had to take her so my wife could go to work.

This discussion has been great and I only hope that we can keep the information flowing. If I find the article of air as fluid, I will definitely pass it on.

[Longshot270]

Originally Posted by Skip_1074

When I read the OP, the combination of the Edge and CAI caught my eye while I was still on the first sentence, and I was actually surprised that nobody else mentioned it.

I understand fluid dynamics, but not to the point that I can confidently speak on it. You are definitely right about air being a fluid and it being tricky. I have searched a little today and I can't seem to find an article that I read on Banks Power, specifically addressing air being a fluid, but here a chunk borrowed from one of their articles:



Hampsterzone, you discussed backpressure in one of your earlier posts. As you notice, backpressure actually creates heat excess heat in the engine acting as a "parasitic loss" in power.

As for the time wasting that I did this morning, I was trying to do some calculations in regards to engine CFM airflow requirements in comparison to the ability of air systems to move them, but unfortunately I was unable to find the capability of the stock air system. But just for and , the max CFM flow of the 5.4L 3V engine at 5500 RPM is 628 based on the calculator that I have.

I would have gone fishing, except for a few things...its was only about 3:30am when I started the post, around 5:00am when I finished it and I'm pretty sure you can't get your line wet until first light. It was about 25 degrees outside and the closest place to go fishing is a GOOD hour plus away. The only reason that I was still up was my daughter had late start at school and I had to take her so my wife could go to work.

This discussion has been great and I only hope that we can keep the information flowing. If I find the article of air as fluid, I will definitely pass it on.

In scientific terms, a gas IS a fluid just as a liquid IS a fluid. The confustions arise when things are translated to common speak because words are not the same.

If your wanting flow bench results, we have some in an ancient article...
http://forum.gopowerhungry.com/2004-...t-results.html

At the current state of technology, our engines are pathetic on mechanical efficiency.

Back pressure also reduces engine efficiency because not all of the exhaust gasses are expelled. For gasses, pressure is equivalent to mass. Here we work backwards. Instead of trying to increase pressure at the cylinder, here we are trying to reduce it. If there is pressure out side of the cylinder then more of the molecules that make up the exhaust gas will stay in the cylinder. Things also start getting real tricky because the exhaust gasses start acting a little different because now we are pushing them with pressure rather than pulling them. You encounter simple logic problems such as exhaust pipe diameters and configurations that reduce performance rather than increase it, along with true impact of obstructions and such. If you go on the larger forums you can see people (like me haha) get chewed on for running baffled mufflers like the flowmasters. The baffles present an obstruction and logically would stop or hinder the flow to cause a decrease in exhaust flow, increase heat, etc. All of that sounds true and to an extent is true, I did see a loss in performance because I tested it at a local drag strip. I lost .07 seconds on a quarter mile run. Exhaust requires more advanced understanding of fluids under pressure because it is very easy to overeastimate and undereastimate the effects of a modification without having a solid understanding of the numbers that cause it. I try to not discuss anything unless I'm able to test it because without facts everything is a WAS guess, epecially for this.

[88Racing]

To put it simply a cai alters the original path of air in which the MAF was calibrated for......
Also
Larger diameters of tubing cause the air intake to move slower across the MAF at a set rpm thus less fuel is delivered bring in a lean condition.....

[88Racing]

Originally Posted by hampsterzone

Excellently put! I appreciate your response. Any thoughts on exhaust causing the O2 sensors to relay lean conditions?

The lean codes from the o2 sensers can be atributed to a vacuum leak occuring after the maf up to the point of combustion......after combustion the exhaust may cause these but before the o2 senser if there are......broken welds, broken header studs, cracked manifolds, bad gaskets.......