I'm sick of trying to decide which intake is best so...

I'm trying to determine the best design for a filter element and its associated duct work. My first plan was to reduce pressure(er...vacuum) drop through the filter by having an over sized element and pipes. Maybe even a 2:1 double filter style setup. But i keep getting this feeling that velocity is another factor i need to look at more. if i increase the duct size ill lose velocity, but i can hear my intake whistling as it sucks in air so...there has to be a lot of extra static pressure? enlarging the duct/filter size would reduce the amount of engine vacuum wasted trying to pull air through the filter right? this should improve-off-the-line or hammer drop performance. I'm fairly certain i want as little restriction as possible.

Question is someone engineered the stock intake the way it is now for a reason. Even most aftermarket intakes stick to the same general guidelines. does anybody have any theories or thoughts about what a change in velocity might affect? for example i'm almost positive the mass air flow sensor would still read the same amount of air coming in.

Thanks in advance!

EDIT: Crap! this is definitely an oldish topic my bad...well for anybody interested Sentient started this thread back in the day... zerothread/294142
Modified by Anthonysflying at 3:26 PM 2/12/2009

A MAF calibration is specific to the things in front and behind it as they can affect the air flow thru the MAF the shape and turbulence.

The sample tube only occupies a small fraction of the MAF area and thus the air flow across the entire area must be homogenious.

The restrictions to air flow into engine after the 14.7 psi pressure are intake valves, MAF, TB, air ducts and final filters in that order.

Most modern engines have less than 1.0 psi [27.7 " H2O] restriction as the flow bench SAE standard is 25" H2O.Paper air filter elements have so much area [iron the convolutions flat] that even the bad ones are less than 1.3" H2O.

Before you waste time measure the air flow restriction to plenum at redline and 4,000 rpm thru all those imaginary wasteful components.

It sounds like inconsistent duct sizing and airflow will throw off the MAF. not to mention there is most likely a lot less restriction than i think.

on a side note, When i get a chance ill figure out what CFM the engine requires at redline.

Hello. Your quetion on intake air flow design reguarding flow rate (velocity) versus initial rev. up lag time is fairly simple in nature. Velocity is indirectly related to pressure in a sense that one end of the travel path has less pressure than the other. Your understanding of negitive pressure, inches of mercury, generated from the downward motion of a piston to closure of exhaust valve and opening of the intake valve is clear. This obviosly means the duct work will only become as usefull in maximum size as the throttle chamber inlet is. Air filtration is there for reasons made obvious but it isn't always the size of the filter that allows for better flow. One should consider the resistance to flow based on filter density. The main reason many are using the cone design is for the slight added swirl effect. Swirl has a hand in velosity. As long as your mass air flow sensor is clean and free from any type of oils or solvents there should not be and issue with your ECM having the ability of compensating for increased flow rate. This is assuming that you have not gone too dramatic with any modifications. Aside from what has already been said, keeping your duct work as stream line, free from restrictions, and as cold as possible, only then will you be able to safely, incure the benifits of adding a cold air intake or air filter modification. My name is Michael Lucas and I am happy to be of any further assistance. Thank You...

If you are really concerned about flow, start with porting the intake manifold. It will really make a difference in spooling (will start between 200 and 500rpm sooner).

another way of getting rid of AFM problem ... is to get rid of the AFM and use a MAP system coupled with an air temp sensor. TBH, you wont feel the difference unless you get real power (500+ ) .