I don't see that happening.


Perhaps not, but often times examples with words are easier to follow than equations.

Here's the data.

Wix 46728 filter for late 99 & up 3" depth, 55 pleats (pleat being counted as the pointy fold opposite of the gasket), 6 1/2" wide. 1/8" glued section at the bottom (or top depending on how you look at it) to hold the pleats in place on the filter.

Wix 46648 for early 99 2" depth, 6 1/2" wide, 79 pleats, same 1/8" glued portion on each pleat.

I'm interested to hear your projected % of effective surface area in this design also

 

Finally another person with common sense. If the engine can only use 400cfm of air at maximum RPM then there is simply zero reason to have a 800cfm filter installed. There is a formula based on engine size, efficiency % and RPM. The numbers don't lie. Ford stuck a gauge on the filter box, once the gauge reads there is a restriction then the engine doesn't have enough air. Simple and well engineered. Read all the threads about engine problems and bad trannies and you'll understand why Ford pays their engineers big dollars to come up with compromises so that the truck stays together for 200k miles. . Start modifying things and you will go faster and make more smoke but I guarantee your truck will come unglued sooner than expected. For all the claims of better miles per gallon that's another load of bull. Ford, GM, Chrysler, Volkswagen you name it they all have tremendous pressure and financial incentives from the government to improve overall fuel efficiency. Don't you think if the engineers could simply redesign the intake and exhaust or reprogram the chip to gain 2mpg they would? Hello? That would save millions on R&D for new engine designs. I don't believe a guy in his garage can improve fuel efficiency by 10% or more when the factories can't do it.

 

I think you oversimplified things here at the end. You have to keep in mind not just fuel economy, but power and reliability when Ford (or the others) design a vehicle. Ford could have easily made the 7.3 get over 25 mpg, but it would have been slower than a bicycle, which means they wouldn't have sold any of them.

One should also consider cost cutting measures employed by Ford in the original design. Improved air flow is not the only reason to move away from the poorly designed stock air box. I dumped my stock set up when I noticed it beginning to allow dirt to get past the filter. CFM airflow doesn't really count for much when it's sucking a lot of dirt along with it.

 

I like Waffles!

 

To recap from part 1... we've got a stadium filled with bees and we're delivering them to a customer's trailer outside using a 1 ft^3 box with a removable lid and we're delivering one boxful each minute which means 1 ft^3/min=1 CFM of bees are flowing from the stadium to the customer's trailer but the customer doesn't trust a CFM measure and he's only willing to pay for the number of bees getting delivered per minute.

In the above analogy the trailer represents the cylinders of an engine and the bees are the air molecules and the payment is HP and EGT control and as we'll see filling the cylinders of an engine from a stadium full of air is almost but not quite the same as filling them from the almost infinite supply of air from the ambient atmosphere.

Since trying to count the number of bees in each boxful is too time consuming and we're likely to get stung as well just what are we to do if we want to get paid? Well of course we hire a wanna "bee" engineer as a consultant and we follow his directions to gather up 100 typical bees at random and weigh them all at once and this gives a total weight of 0.0481 lb which we then divide by 100 to get the weight of an average bee Wab as Wab=0.000481 lb and the wanna "bee" engineer says the proper way to write this number is Wab=4.81x10^-4 lb.

If we could repeat this procedure for actual for dry air molecules by gathering up 100 of those at random we'd wind up weighing 23 O2 molecules and 77 N2 molecules and dividing this total weight by 100 would give the weight of an average molecule Wam as Wam=1.0604x10^-25 lb and this is an exact value for the average molecular weight of dry air which includes the trace amounts of other molecules in air. So in this analogy each bee weighs (4.81x10^-4)/(1.0604x10^-25)=4.54x10^21 times more than an average air molecule does.

Now we weigh the empty 1 ft^3 box with its removable lid in place and then go inside the stadium and remove the lid to let the box fill up with bees and then we replace the lid and go outside and weigh the box again and subtract the empty weight to get the net weight of all the bees inside the box Wnb as Wnb=0.831 lb and to please the wanna "bee" engineer we write this number as Wnb=8.31x10^-1 but then he says if there's not a whole lot of zeros between the decimal point and the first digit to confuse the issue that just writing Wnb=0.831 lb is also acceptable.

Now we calculate the number of bees in the box Nb by dividing the net weight of all the bees inside the box Wnb=8.31x10^-1 lb by the average weight of a bee Wab=4.81x10^-4 lb and we get Nb=(Wnb)/(Wab)=(8.31x10^-1)/(4.81x10^-4)=1,728 bees in the 1 ft^3 box and since there's 12^3=1,728 in^3 in the box this works out to one bee in each in^3.

If we collected a boxful of air molecules from an ambient sea level atmosphere at a 70 F temperature we'd find that the net weight of all the air molecules inside the box Wnm was Wnm=0.075 lb=7.5x10^-2 lb and by dividing the net weight of all the molecules inside the box Wnm=7.5x10^-2 lb by the average weight of a molecule Wam=1.0604x10^-25 lb we'd get Nm=(Wnm)/(Wam)=(7.5x10^-2)/(1.0604x10^-25)=7.073x10^23 molecules in the 1 ft^3 box and since there's 12^3=1,728 in^3 in the box this works out to 4.093x10^20 molecules in each in^3.

Using the above calculations the wanna "bee" engineer explains to the customer that flowing bees from the stadium to the customer's trailer at a 1 ft^3/min=1 CFM rate is equivalent to delivering bees at a mass bee flow MBF lb/min of MBF=0.831 lb/min and that this 0.831 lb/min MBF is delivering bees at the rate of 1,728 bees/min so that MBF meets his criteria as an acceptable measure for getting paid.

If we're flowing 70 F sea level ambient air to the cylinders of an engine at a 1 ft^3/min=1 CFM rate the mass air flow MAF lb/min is MAF=0.075 lb/min and this 0.075 lb/min MAF is delivering air molecules at the rate of 7.073x10^23 molecules/min.

Well since the wanna "bee" engineer isn't getting paid until the job is done he says I've got some ideas for speeding up the rate of bee delivery but you'll have to promise me a bigger cut of the action before I tell you how to do it. Since time is money there's enough extra profit to keep everyone satisfied so you agree to the deal.

So he says we can speed things up by not bothering to weigh each boxful of bees and also by stuffing more bees into each boxful under pressure and I'll explain to the customer how the "kinetic theory of ideal bees" can be used to calculate the number of bees in each one of these pressurized boxfuls.

First I'll explain that the number of bees Nb=1,728 bees in the current boxfuls which have a box volume Vb=1 ft^3 represents a bee number density BDn given by BDn=(Nb)/(Vb)=(1,728 bees)/(1 ft^3)=1,728 bees/ft^3 and that since the volume of the stadium is almost infinite compared to the volume of the 1 ft^3 box that the bee number density in the stadium remains at a constant value of 1,728 bees/ft^3 even though we're removing some boxfuls of bees to fill his trailer.

Then I'll explain that according to the "kinetic theory of ideal bees" we can double the number of bees in each boxful by doubling the bee pressure inside the box and that we'll do this by using the stadium's air handling system to blow a whole lot of bees into the lobby and hold them trapped there under pressure as we shut the access door to the main stadium and then we'll fill the 1 ft^3 box from the lobby.

So the wanna "bee" engineer proceeds to explain to the customer that inside the box the bees are buzzing around in a random chaotic manner with an average random bee velocity Vrb and that they're bumping into each other and into the walls of the box and that each time a bee collides with something it hits with a tiny impact bee force Fb and that the accumulation of these bee impacts Fb per unit area causes a bee pressure Pb and that Fb depends on Vrb and that a bee's average kinetic ENERGY KEab is proportional to its average weight Wab times the square of its random bee velocity Vrb and that a bee's average kinetic ENERGY KEab is also proportional to its absolute bee temperature Tab so that KEab~Tab and that the Tab is the parameter that can be easily measured to get KEab and that when you put this all together Pb is proportional to the total kinetic ENERGY of all the bees in the box which is (Nb)(KEab) divided by the volume of the box Vb so that Pb~{(Nb)(KEab)}/{Vb} and that we'll measure Pb with a bee pressure gauge and we'll measure Tab with a bee thermometer and then use Tab to get KEab and then since we already know Vb we can solve for Nb to get the number of bees in each one of the pressurized boxfuls.

Well needless to say before the wanna "bee" engineer got very far along with his explanation the customer's eyes were rolling around like the wheels in a slot machine! Since this plan was only going to double the bee delivery rate anyway it was abandoned in favor of a much better one which will be explained in the next installment. Once the trailer gets filled to capacity with bees some bee food is injected and then the feeding frenzy begins but as it turns out there's not enough food available to satisfy all the bees and that's where the plot thickens.