This may or may not sound like a newb question but out of pure curriosity, is there an optimal size for an air filter?(trust me i looked, if i looked over it i apologize) I understand that there are numerous factors that eventually decide which to go with but is there a limit on too big? For understanding purposes and if incoorect please correct me, but any one engine can take an xxx CFM of air at a given time. obviously you do not want a filter that has a limitation of xxx amount CFM lower than what the engine can take in at any given rpm. but lets say that same filter in design, material, mounting point, etc. was made larger, far exceeding what the engine needs could a problem/peak of incoming air occur? Also with a larger amount of area that air could be sucked from due to filter size, theoritcally a larger volume of air can be taken into the engine of course with the limitation of how much cfm is taken in/needed at a given rpm (i may of just answered my question). But is velocity sacraficed due to the increase in volume?

Also from a perspective of seeing the engine as a vaccum (correct me if i'm wrong) but lets say i place a filter on the end of the vaccuum hose with a limitation of xxx cfm that the vaccuum can suck at its full power, but next i place a filter much larger than before and far exceeds the xxx amount of cfm required, its going to suck as much air as possible at full power that it needs/can. Obviously the dimensions/overall shape of the filter matter accordingly but could there be that much of a velocity difference in the intake charge that it can show ill affects?

(After the 5 or so mintuies that i typed this out i realized i have no idea what i just said . I apologize for the gramatical, spelling, and informational errors written above.)

Edit: uhh yeah still have no idea what i wrote, Tired as hell, i apologize.

 

The engine does not suck in air the earth's supercharger [14.7 psi] forces the air thru the filter to refill the cylinder that were pumped partially empty.

At WOT the restrictions are 25-28" WC the bulk comes from TB plate [7"] and MAF [7"] and the intake valve curtain area and all the rest [11-14"]

USE A manometer to measure the pressure differential between atmospheric and engine side of air filter.

Most modern [last 19 tears of design] oem filters are so good that they have less than 1.0 inches of water column [WC] restriction at WOT REDLINE . 1/27.7 = 0.0361 psi and 1.0 psi = 6.8% restriction so ~= 0.245% power loss...........on a 300 HP engine that would be 3/4 of a HP and less than a lb/ft of torque.

The horsepower wars have squeezed every avenue of restriction out of performance engines, unfortunately people still making their living from selling aftermarket air filters and CAI must still lie [confuse the truth] to you or find another line of work or let their families starve! All in all the least expensive air filter changed frequently is much better than the most expensive changed less frequently.
NOTICE Lot's of the test reference big old US engines which were not designed or optimized to perfection.

Iron flat the pleats on any air filter element to get true square area then correct for material thickness.

Most cone filters have less than oem area and use thinner filtration medium to make up the difference --- hopeing the oil catches some of the dirt.

Anyway divide ci by 2 and multiply by rpm then dive by 1728 = CFM which must be reduced by VE to get real inflow to fill cylinder.

A 215 engine @7000 with 75% VE = ~ 326 CFM
Another way to look at is is 1HP need 1.2 CFM of air flow.

 

Truckers are very familiar with manometers they may just not use the name, as diesels have a manometer to indicate filter flow restriction and when to change the filter............just as commercial building air handlers do.

http://www.bobistheoilguy.com/airfilter/airtest2.htm

This should scare you about dirt flow testing!
http://www.bobistheoilguy.com/airfilter/airtest3.htm

The oiled filter companies will say the black dirt on the secondary [after first filter] is not dirt but some imaginary thing the tester did to take food from their families but it looks and tastes and smells like dirt - it probably is dirt.

Thank goodness if you advertise and sponsor enough hack drivers and cars the truth can be confused in enough buyers minds to stay in business.