Originally Posted by Beechkid

Of course you realize in a normally aspirated engine, the aftermarket CAI's are 100% useless.....
Testand Corporation conducted an ISO standards test on automotive air filters which can be viewed at this link: http://www.dieselbombers.com/chevrol...r-testing.html
The 5.4 V8 for example if close to stock can only suck in a maximum of 480 cfm and a flat panel filter will flow 500 cfm, there is simply no way any CAI on a relatively stock engine can increase the air flow enough to exceed the ECM’s ability to adjust and maintain the correct fuel mixture. The only reason for the “custom” program to support the CAI is because the design is poor resulting in false readings from the air intake sensors, etc….period! If you look at the dyno charts from many of these supposed HP/TQ increases, they are typically around 5%-7% at peak rpm ranges…….guess what, 5% is a standard deviation even amongst mfg dynos and if you go to this link http://www.fordracingparts.com/downl...ceTechTips.pdf the engineers at Ford racing have a article on just exactly how these “tuners” play games with the hp/tq ratings, how calibration can cause misleading dyno results, & some of the “tricks” that are used to gain supposed power increases when in fact, managing your engine….. and the most important item is……these “expert tuners” (at least most) do not have or choose not to test their results (in comparison to the oem intakes) during actual vehicle motion (or simulation- such as a wind tunnel) as the oems do. What many view as an issue (is the plastic intake tube with its noise canceling design) actually increases air pressure. It is the same hydraulic concept used by fire fighters creating water supply where psi is low. By having the air cross the path at a 90 degree angle, the pressure is increased proportionally. Fire fighters use what is called a “4-way valve” or “Blake Valve” at the hydrant where the water is cycled through the fire engine (pump) and sent back into the valve crossing the water flow at a 90 degree angle. In this case it also acts as a sound canceling device! At low speeds, this can reduce the flow a tad (which is what most “feel”), but in terms of peak hp/tq, a good high flow filter is all that is needed.