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Modern engines are extremely adaptive, so adding a high flowing intake that allows more air into the throttle body and engine, all other things held constant, wiill not make extra power.

In simplistic terms here is why: for a given gas pedal location the ecu is going to provide a given amount of fuel from the injectors AND try to maintain a given Air to Fuel A/F mixture.

So if you introduce a high flow intake that attemps to provide more flow to the engine here is what happens:

At a given amount of gas the ECU will listen to the Mass Air Flow Sensor to determine how open the throttle body butterfly valve should be. If it sense too much air (due to the high flow intake) it closes the valve a bit until it is happy with the amount of air flowing past the MAF sensor. So the Throttle body valve replicates the restriction of the stock intake box no matter how much extra flow the high flow intake is willing to accomodate. So with an ECU that has adjusted to a high flow intake, when your foot is all the way to the floor on the gas pedal the butterfly valve is actually not wide open.

Here is a link and excerpt of injen's realization of this in 2003 (I encourage interested people to read the whole link):
Injen - Performance Air Intake Systems, Exhaust Systems, Turbo Components, and Air Filters for Cars, Trucks, Motorcycles, ATV's, Boats and more!

"In 2003, Injen Technology started designing two separate intake systems: one for the 2003 Mazda 6 and one for the 2002 Subaru WRX. It was business as usual inside Injen's R&D department, but this time, something had changed within ECM and how quickly it interpreted the information it received from various sensors. No matter what intake tube design the R&D department came up with, the ECM would adjust the air/fuel ratio from one hour to the next to compensate for the changes our intake provided. This might not sound like a big deal to most, but Injen Technology intakes rely on two key characteristics to produce power: improved airflow AND a tuned air/fuel ratio to extract every last ounce of safe power. If the ECU was now "tuning" around Injen air/fuel adjustments, this obviously posed a severe problem... "

So with all this being the case, the only way to make extra power from higher flowing intakes is to trick the MAF into thinking less air is going into the engine than really is allowing the engine to run more lean, but with greater pumping efficiency, which is ultimately how intakes always made the extra power and fuel efficiency gains on older cars who's ECU's did not recalibrate.

Injen's solution was to utilize the Bernoulli principle of venturi nozzles to trick the MAF Sensor (excerpted from the same injen link):

"After a few sleepless nights, Injen engineers started considering incorporating a venturi type tube along the path of an intake tract to control the flow rate to the mass air flow sensor. By learning how to control air speed and the resultant pressure, Injen engineers were able to maintain the desired temperature of the "hot wire" located inside the mass air flow sensor without the use of external electronics! In doing so, Injen now had the method to tune the air/fuel ratio for optimum power built directly into the Injen intake system."

Now Corksport has also commented on having substantial intake power gains from their SRI, and if you look at the design: large diameter conical intake in front of a relatively small MAF housing which exits to a expanding relatively larger flex coupler into the throttle body, the entire Corksport SRI unit is also essentially a tuned venturi nozzle as well, just a little less obvious than injen's crimped pipe. So the Corksport unit is also tricking the MAF into thinking less air is flowing into the engine than really is.

For all this, intake power gains are still in the 5% or less range that they always were for high flow intakes before engines became more adaptive, so new intakes are not an improvement over old ones, they are just maintaining the gains that were always possible due to greater pumping efficiency as a result of a high flow intake, despite the efforts of the MAF and ECU to prevent it.
 

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Modern engines are extremely adaptive, so adding a high flowing intake that allows more air into the throttle body and engine, all other things held constant, wiill not make extra power.

In simplistic terms here is why: for a given gas pedal location the ecu is going to provide a given amount of fuel from the injectors AND try to maintain a given Air to Fuel A/F mixture.

So if you introduce a high flow intake that attemps to provide more flow to the engine here is what happens:

At a given amount of gas the ECU will listen to the Mass Air Flow Sensor to determine how open the throttle body butterfly valve should be. If it sense too much air (due to the high flow intake) it closes the valve a bit until it is happy with the amount of air flowing past the MAF sensor. So the Throttle body valve replicates the restriction of the stock intake box no matter how much extra flow the high flow intake is willing to accomodate. So with an ECU that has adjusted to a high flow intake, when your foot is all the way to the floor on the gas pedal the butterfly valve is actually not wide open.

Here is a link and excerpt of injen's realization of this in 2003 (I encourage interested people to read the whole link):
Injen - Performance Air Intake Systems, Exhaust Systems, Turbo Components, and Air Filters for Cars, Trucks, Motorcycles, ATV's, Boats and more!

"In 2003, Injen Technology started designing two separate intake systems: one for the 2003 Mazda 6 and one for the 2002 Subaru WRX. It was business as usual inside Injen's R&D department, but this time, something had changed within ECM and how quickly it interpreted the information it received from various sensors. No matter what intake tube design the R&D department came up with, the ECM would adjust the air/fuel ratio from one hour to the next to compensate for the changes our intake provided. This might not sound like a big deal to most, but Injen Technology intakes rely on two key characteristics to produce power: improved airflow AND a tuned air/fuel ratio to extract every last ounce of safe power. If the ECU was now "tuning" around Injen air/fuel adjustments, this obviously posed a severe problem... "

So with all this being the case, the only way to make extra power from higher flowing intakes is to trick the MAF into thinking less air is going into the engine than really is allowing the engine to run more lean, but with greater pumping efficiency, which is ultimately how intakes always made the extra power and fuel efficiency gains on older cars who's ECU's did not recalibrate.

Injen's solution was to utilize the Bernoulli principle of venturi nozzles to trick the MAF Sensor (excerpted from the same injen link):

"After a few sleepless nights, Injen engineers started considering incorporating a venturi type tube along the path of an intake tract to control the flow rate to the mass air flow sensor. By learning how to control air speed and the resultant pressure, Injen engineers were able to maintain the desired temperature of the "hot wire" located inside the mass air flow sensor without the use of external electronics! In doing so, Injen now had the method to tune the air/fuel ratio for optimum power built directly into the Injen intake system."

Now Corksport has also commented on having substantial intake power gains from their SRI, and if you look at the design: large diameter conical intake in front of a relatively small MAF housing which exits to a expanding relatively larger flex coupler into the throttle body, the entire Corksport SRI unit is also essentially a tuned venturi nozzle as well, just a little less obvious than injen's crimped pipe. So the Corksport unit is also tricking the MAF into thinking less air is flowing into the engine than really is.

For all this, intake power gains are still in the 5% or less range that they always were for high flow intakes before engines became more adaptive, so new intakes are not an improvement over old ones, they are just maintaining the gains that were always possible due to greater pumping efficiency as a result of a high flow intake, despite the efforts of the MAF and ECU to prevent it.
Here's a small detail that makes the above theory collapse like a house made of cards: "high flow" is JUST A NAME. What makes you think Mazda's OEM intake is not "high flow" already?

Intake calibration and exhaust make a complete system. You need a modified exhaust, with a modified setting for the engine for an aftermarket intake to be beneficial. But the catch is that factory intake is already "high flow", and with a firer flowing exhaust there is no need to change an OEM intake, just engine setting.

Intake has no moving parts, it's just a filter, for Christ's sake!!! It cant force air into an engine, an air merely passes through it!!! These are BASICS!
 

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Here's a small detail that makes the above theory collapse like a house made of cards: "high flow" is JUST A NAME. What makes you think Mazda's OEM intake is not "high flow" already?

Intake calibration and exhaust make a complete system. You need a modified exhaust, with a modified setting for the engine for an aftermarket intake to be beneficial. But the catch is that factory intake is already "high flow", and with a firer flowing exhaust there is no need to change an OEM intake, just engine setting.

Intake has no moving parts, it's just a filter, for Christ's sake!!! It cant force air into an engine, an air merely passes through it!!! These are BASICS!
Except the filter media can be extremely restrictive, causing less air to get to the engine. I noticed a MPG change when I switched to a K&N filter, the only thing I can think is that its allowing more air through because it is a cotton media rather than paper. Aftermarket intakes may then attribute themselves as high flow because they can use paper filters and achieve better air flow than a similar paper media in the stock air box.
 

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Debunking the K&N Myth – Why OEM is Better

For decades, the aftermarket hot rod, racing and tuning communities have relied on oiled-media filters to free up that extra few horsepower. In fact, it’s often one of the FIRST modifications many automotive enthusiasts do to their car. K&N filters, to their credit, is generally known to be the top name in oiled filters, and they do a great job of building a quality product. However, it’s always important to evaluate the claims and see exactly what you’re getting for your money.

This report shows, with empirical data and sound reasoning, why OEM filters perform better in a variety of areas.
Special thanks to Arlen Spicer and all others involved in making this information available.

A note from the author:
The reason I started this crusade was that I was seeing people spend a lot of money on aftermarket filters based on the word of a salesperson or based on the misleading, incomplete or outright deceiving information printed on boxes and in sales literature. Gentlemen and Ladies, marketing and the lure of profit is VERY POWERFUL! It is amazing how many people believe that better airflow = more power! Unless you have modifications out the wazoo, a more porous filter will just dirty your oil! Some will say, I have used aftermarket brand X for XXX # years with no problems. The PROBLEM is you spent a chunk of change on a product that not only DID NOT increase your horsepower, but also let in a lot of dirt while doing it! Now how much is a lot? ANY MORE THAN NECESSARY is TOO MUCH!

Others are persuaded by the claims of aftermarket manufacturers that their filters filter dirt “better than any other filter on the market.” Sounds very enticing. To small timers like you and me, spending $1500 to test a filter sounds like a lot. But if you were a filter manufacturer and you believed your filter could filter dirt better than any other media on the market, wouldn’t you want to prove it? Guess what. Test your filter vs. the OE paper. It will cost you $3000 and for that price you will have the data that you can use in your advertisements. Your investment will be returned a thousand fold! EASIER than shooting fish in a barrel! So why don’t these manufacturers do this? Hmmm? Probably not because they would feel guilty about taking more market share.

Now I am not saying that ALL aftermarket filters are useless. A paper filter does not do well if directly wetted or muddy. It may collapse. This is why many off-road filters are foam. It is a compromise between filtering efficiency and protection from a collapsed filter. Now how many of our vehicles collapse their filters from mud and water?

However, if a filter is using “better airflow” as their marketing tool, remember this….Does it flow better? At very high airflow volumes, probably. BUT, our engines CAN’T flow that much air unless super-modified, so what is the point? The stock filter will flow MORE THAN ENOUGH AIR to give you ALL THE HORSEPOWER the engine has to give. And this remains true until the filter is dirty enough to be recognizeable. At that point performance will decline somewhat. Replace the filter and get on with it.
Hopefully the results of this test will do 2 things. Shed some light on the misleading marketing claims of some aftermarket manufacturers and/or give us new insight on products already on the market that are superior to our OE filter.

SCOPE:
This report presents the results of an ISO 5011 test of several air filters designed for the GM Duramax Diesel. The test was independently performed under controlled conditions using a $285,000 machine at Testand Corp of Rhode Island (manufacturer of the machine).
Arlen Spicer, a GM Duramax Diesel owner/enthusiast organized the test. Testand offered to perform the tests at no charge. (These tests typically cost approx $1700.00 per filter). Ken (and employee of Testand), a Diesel enthusiast and owner of a Ford Power Stroke Diesel, shared Arlen’s interest in performing an accurate unbiased test of different types and brands of diesel engine air filters.
The filters used in the test were purchased retail and donated by Arlen and other individual Duramax Diesel owners. The detailed reports from the test have been compiled and are presented in the following pages. The final pages of this report present the behind the test.

ISO 5011 Test:
The ISO 5011 Standard (formerly SAE J726) defines a precise filter test using precision measurements under controlled conditions. Temperature & humidity of the test dust and air used in the test are strictly monitored and controlled. As Arlen learned in attempting his own tests, there are many variables that can adversely affect filter test results. A small temperature change or a small change in humidity can cause the mass of a paper filter to change by several grams.

To obtain an accurate measure of filter efficiency, it’s critical to know the EXACT amount of test dust being fed into the filter during the test. By following the ISO 5011 standard, a filter tested in Germany can be compared directly compared to another filter tested 5 years later in Rhode Island. The ISO 5011 filter test data for each filter is contained in two test reports; Capacity-Efficiency and Flow Restriction.

Capacity and Efficiency:
The Capacity and Efficiency test report presents the test results of feeding an initially clean filter with PTI Course Test Dust (dirt) at a constant rate and airflow. The course test dust has a specific distribution of particle sizes ranging from less than 2.5 microns to greater than 80 microns (see table below).

Every filter is initially tested at 350 CFM and the Initial Restriction or differential pressure across the filter is recorded in IN-H20 (Inches of Water). The filter is then tested by feeding test dust at a nominal rate of 9.8 grams per minute with a constant airflow of 350 CFM. The test is continued until the flow restriction exceeds the Initial Restriction + 10 IN-H20.

At this point the test is terminated and the amount of dust passed through the filter (Accumulative Gain) is measured. Dirt passing through the filter is captured in the Test Station’s Post Filter. The exact amount of dirt passed is determined by measuring the before and after weight of the Post Filter.
Similarly, the amount of dirt retained by the Filter under test – Accumulative Capacity – is measured by taking the difference between the before and after weights of the Filter. From these results the overall % Efficiency of the filter is calculated. This test also indicates how long a Filter will last before replacement is required (or cleaning for reusable filters).

Flow Restriction:
This report presents flow restriction of a clean filter resulting from an increasing airflow. The differential pressure restriction across the filter is reported in inches of water (IN H2O) versus Air Flow in cubic feet per minute CFM.

Data from these reports has been compiled and presented in the following bar graphs, plots and data tables.

Filtering Efficiency:
Filtering efficiency is a measure of the filter’s overall ability to capture dirt.



Accumulative Capacity:

“Accumulative Capacity” is a measure of dirt holding/loading capacity before reaching the maximum restriction limit.
Initial Restriction + 10 IN-H20.



Accumulative Gain:

“Accumulative Gain” is the total amount of dirt that passed through the filter during the test.



(Note: The Purolator was reported to have a seal malfunction during the test and passed more dirt than it would have with a good seal.)

Initial Restriction:
Initial Restriction is the Filter under test’s resistance to flow at 350 CFM.



Dirt Passed Versus Total Test Time:

This graph shows each the duration of each filter’s test versus dirt passed (Accumulative Gain).



(Note: The Purolator was reported to have a seal malfunction during the test and passed more dirt than it would have with a good seal.)
In the chart above it’s important to note the different test durations for each filter. The AC Delco filter test ran for 60 minutes before exceeding the restriction limit while the AMSOIL and K&N tests each ran for 20 and 24 minutes respectively before reaching max restriction.

In 60 minutes the AC Filter accumulated 574gms of dirt and passed only 0.4gms. After only 24 minutes the K&N had accumulated 221gms of dirt but passed 7.0gms.

Compared to the AC, the K&N “plugged up” nearly 3 times faster, passed 18 times more dirt and captured 37% less dirt. See the data tables for a complete summary of these comparisons.

Dust Loading:
The dust loading curves show graphically how each filter responded to a constant 9.8 gms/min dust flow before reaching the maximum restriction limit.



It’s interesting to note the shape of these Dust Loading Curves. The AC and Baldwin filters each had near linear responses until reaching maximum restriction. Restriction for these filters increased at a constant rate versus the 9.8 gms/min dust feed rate.

The other filters, most notably the oiled reusable types, had an exponential loading response before reaching maximum restriction. These filters had a lower initial restriction, but they became exponentially more restrictive under a constant flow of dirt.

This runs counter to the “myth” that oiled media filters actually “work better” as they get dirtier.

Also notice the length of the curves as it shows the relative test time for each filter (time to max restriction).
Restriction to Flow:The Restriction to Flow curves graphically show how each “clean” filter responded to a steadily increasing flow of air up to 350 CFM.



The Flow Restriction response curves for each filter have the same basic shape. However, note how the AC Filter, which passed the smallest amount of dirt and had the highest dirt capacity and efficiency, also had the highest relative restriction to flow. The less efficient filters correspondingly had less restriction to flow.

This illustrates the apparent trade-offs between optimizing a filter for dirt capturing ability and maximum airflow.

We hope you’ve enjoyed this article – There’s a lot more Nissan technical articles and useful “how-to” automotive tutorials here – Plus, the friendliest community of car enthusiasts on the web!

K&N Air Filter Review - Debunking the Myths (and why OEM is better)
 

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I wad wondering when someone would bring that up. K&N is well known to be one of the worst things you can do to your poor little engine, at least among enthusiast groups. Max effort? Sure go for it.... care about engine life? DONT DO IT.
 

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To this time I have not said. Put in a K&N it will get you better anything. I said I have it in mine and I noticed an MPG increase.

I am not trying to start a fight, this has already been done. Dust and other crap will get in anyway, OEM can trap more because its a tighter woven material that also means less airflow. Paper will trap more vs cotton.

In combustion if the air to fuel ratio in a certain amount of time isnt met one or the other has to increase. With a higher flowing air filter less fuel has to be forced in to cause detonation.

Which is why I ALSO said these aftermarket airflows give more air flow while allowing you to have a paper media. Thus best of both worlds. Goodness, I am waiting to be able to order the SRI from corksport because of this.

As far as dust and other particles in the engine, you have an oil filter to help with that too, and unless you're running your engine over 6000 miles(also can be considered bad for your engine even with some synthetics). You're just damaging your engine anyway.

Edit:

I've also seen the charts, the reviews, heard the horror storied. I've also heard them about certain oil filters, certain oils, etc. The only way you can be sure is to do for yourself these days and I am doing and reporting. If you dont want to do it, fine. All I am is someone out there willing to help provide information that they have. Some people consider lowering cars: bad, aftermarket oversized/undersized tires: bad, it can go on and on. Yet others are ready to jump on and praise the people who find the information on these.... why? because they want to look good? Some provide awesome functionality but at the cost of what is 'approved' for the vehicle. Bash me all you want, bash K&N all you want. I just have the info, I like it. Oil is being changed after 4000 miles on dealer oil to amsoil + moly(some people have negatives about this too... who knew).
 

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Sorry, I tend to disagree but wrong answer... :D

Moral of the story: Always do your HOMEWORK (apparently, many here do...but not everyone). :)
Eh, Its not really a problem. I completely agree that the K&N filters let more stuff in. That its the worst thing for your engine? Hardly.

For some people just the way they drive their car is worse for the engine.

Hell, I spent a week deciding about getting amsoil, the other option was royal purple. Just because someone's UOA showed it contained high levels of moly and its GF-5 compliant, like the mazda oil. Others have had bad times.

I am not looking for a miracle car power maker, but at the same time I look for best and the worst of reviews. I come to my own conclusions after that. For K&N, their cotton oiled filters I saw most people who complained about oil getting on their MAFs or the filter being sucked in because it wasnt firm enough most had some sort of forced induction.

Can enthusiasts used to all sorts of weird things to their cars just for fun, I know the internet is a place for constant disagreement but I try to look beyond that.

My point is:
Is your opinion worth while? YES.
Is it fair to say that what someone else does is the worst thing ever just because you dont do it? Not so much.
Can we just accept that each of us enjoys trying different things? I hope..
 

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My point is:
Is your opinion worth while? YES.
Is it fair to say that what someone else does is the worst thing ever just because you dont do it? Not so much.
Can we just accept that each of us enjoys trying different things? I hope..
Opinion? What opinion...

An opinion is subjective.

I am just sharing factual information here, and it was proven. Just trying to help here.

Now...how you use that information, to beleive or act upon it or not and what you think about it...it is all up to you.

Whatever it is....makes no difference to me.
 

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Except the filter media can be extremely restrictive.
Why? Why would it be EXTREMELY restrictive??? Where do you get this phantom premise??? I do understand that you need this premise for your theory to work, but it does not mean you have to make it up!

Why do you think that engineers that work for an auto manufactures are idiots, and dudes working at injen and corksport are smart????:eek::eek::eek:
 

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Why? Why would it be EXTREMELY restrictive??? Where do you get this phantom premise??? I do understand that you need this premise for your theory to work, but it does not mean you have to make it up!

Why do you think that engineers that work for an auto manufactures are idiots, and dudes working at injen and corksport are smart????:eek::eek::eek:
When I say that I mean compared to other media. They allow for good air flow and great filtration. But there has to be a trade off with higher filtration. I dont recall saying anyone is an idiot at one place and others at another are smart.

Also you're helping what I said, why would anyone change their struts and springs?, get larger tires?, etc. Those are by auto manufacturers and thus 'perfect and right' for the car.

Opinion? What opinion...

An opinion is subjective.

I am just sharing factual information here, and it was proven. Just trying to help here.

Now...how you use that information, to beleive or act upon it or not and what you think about it...it is all up to you.

Whatever it is....makes no difference to me.
And that was taken out of context. I didnt mean it in reference to what YOU shared. Just saying "hey lets work together that against each other". That was just an end to what I had to say, not an attack at your information.
The your here would have best been one as to say everyone(including myself), not you specifically.
 

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Persecutory delusions.

Don't tell me you're going paranoid on us, now. :lol:
I have to now, it feels like I am being attacked. I said before in a previous post that I agree with you on how the filter lets more particles in. Yet other comebacks seem to ignore that.

You're right about the air filters. What I am saying is with the larger tubing, and changed from the air box... provides more air and a larger filter area with a tighter form of filter media(paper like OEM). Even today my car had hesitation jerking, had them with the paper media too but more times in stop and go traffic. The same problem occurred with first SRI corksport released. This is the main reason I want the new one(and because I like messing with the car, its fun).
 

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I have to now, it feels like I am being attacked. I said before in a previous post that I agree with you on how the filter lets more particles in. Yet other comebacks seem to ignore that.

You're right about the air filters. What I am saying is with the larger tubing, and changed from the air box... provides more air and a larger filter area with a tighter form of filter media(paper like OEM). Even today my car had hesitation jerking, had them with the paper media too but more times in stop and go traffic. The same problem occurred with first SRI corksport released. This is the main reason I want the new one(and because I like messing with the car, its fun).
Attacked!? You are something else..You think too much. :lol:

I'm not out here to prove I'm right. Like I said, I'm just sharing factual information and just trying to be of help. That is all.

Hesitation, jerking (esp in stop and go traffic)..and manipulation of the air intake is involved.

Reminds me so much of an MAF sensor issue...when I did just the same (like you did)..."messing around" with the air intake on my old German. True enough, it was...and it got dirty and grimy.

How the MAF got dirty...what do you think.
 

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Attacked!? You are something else..You think too much. :lol:

I'm not out here to prove I'm right. Like I said, I'm just sharing factual information and just trying to be of help. That is all.

Hesitation, jerking (esp in stop and go traffic)..and manipulation of the air intake is involved.

Reminds me so much of an MAF sensor issue...when I did just the same (like you did)..."messing around" with the air intake on my old German. True enough, it was...and it got dirty and grimy.

How the MAF got dirty...what do you think.
Also happened on the stock. And just very slight on creeping speeds. I cant wait until I can get the SRI though.

Also.. yes... I do think too much. I wish I could stop but it just happens. One day it may also take over.
 

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Wouldn't a larger diameter intake allow more air flow by volume? So going from a 2" (diameter) intake to a 3" (diameter) intake would allow for more than double the air volume to make it to the engine in the same amount of time. More volume in the same amount of time would mathematically mean, the flow has gone up? Am I missing something?

Then from an economical stand point of a business, if it truly offers nothing, then why sell it. Pretty sure it has to do something. That is assuming we are also talking about CAI and not just drop in filters.
 

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And Corksport finally has it up on the website. And it looks even better than the pre march 2013 version.

I am changing my oil this weekend, going back to the stock filter and will be ordering it either near the end of the month or early next month.

Get back to the stock feel so I can feel the difference with the CS. I'm so excited.

Edit:

Also, @ExB5, didnt you mention before whether your old Passat was Turbo or not in our lasy K&N argument?
 

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Edit:

Also, @ExB5, didnt you mention before whether your old Passat was Turbo or not in our lasy K&N argument?
It had an ITG foam type pre-oiled air filter...same concept as K&N. It did help breathe the 1.8T better initially...but it brought along more issues than it's supposed "benefits". Hesitation, jerking, clogged (and ruined) MAF sensor, rough idling, etc. Totally not worth it. More cons than pro (1).

Yeah, I see myself in your spot, right now...back then, it was a dumb move, in my part to use the ITG. The difference now between us, I wisened up and learned from that fault. I'm not about to make that same mistake twice (to use an aftermarket air filter or intake) to my new M6.

But then again, it is your car after all...so you can do as you please. Whatever your call, it makes no difference to me.
 

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Wouldn't a larger diameter intake allow more air flow by volume? So going from a 2" (diameter) intake to a 3" (diameter) intake would allow for more than double the air volume to make it to the engine in the same amount of time. More volume in the same amount of time would mathematically mean, the flow has gone up? Am I missing something?

Then from an economical stand point of a business, if it truly offers nothing, then why sell it. Pretty sure it has to do something. That is assuming we are also talking about CAI and not just drop in filters.
Think of the main parts of the intake in order:
Filter > MAF (Tube) > Throttle Body > Intake Manifold > Intake Valves > Cylinder

The cylinder's maximum volume is already set by displacement
The intake valves's timing and lift are already preset by camshaft design
The intake manifold's runner lengths and materials are manufactured
The Throttle Body is a pre-set size and computer controlled (this is irrelevant)
The MAF & subsequent size is roughly equivalent to the throttle body size

This leaves only the filter element. And in a 185hp car, this is irrelevant because:

1. The engine, in basic principle, is an air pump. To produce maximum power requires maximum air volume both entering and leaving. Without forced induction, there is a maximum that can be achieved.
2. Anything other than full throttle produces a high intake vacuum (air starvation) in the manifold
3. Replacing a part which will reduce this vacuum (aka "high-flow" intake) will simply have the same effect as having a wider throttle opening as it simply makes more air available at any given time/throttle load

Which is fine, except that:
1. The rate at which the air can be drawn in is dependent on the valvetrain, RPM and throttle opening. It should be assumed that wherever a manufacturer can achieve more power (a large filter element with a high flow system), they would have done so already to the point where anything larger or higher flow isn't necessary.
2. The fuel management is constantly trying to achieve "stoichiometry" equating to 15.1 parts air to 1 part fuel - perfect combustion
3. There are probably larger obstructions in the intake than the air filter element, for example, if the design bottleneck exists at the MAF tube, throttle body, manifold, or simply from intake valves with a modest lift and duration, then changing the filter element will accomplish nothing except for #3 listed above.

The MAF has a purpose of notifying the ECM how much air is travelling through the intake, so that the fuel system can modify injector pulse cycles to achieve stoichiometry.

Fooling the MAF into thinking there is either more or less air will change your fuel trim (lean or rich), as the ECM will still add fuel as per it's readings. In addition they are often attached to screens used to straighten the air out. They are designed for that particular airstream. Running rich or lean will cause issues in durability (and less power to boot).

Built engines with aggressive intake setups also have aggressive exhaust setups.

There are minor concessions for intake noise created from the factory (shape of the airbox, MAF screens, etc). Changing the element and intake tube might yield 2-3hp, and a more "aggressive" throttle (simply by reducing the vacuum in the intake - removing a restriction).

Remember, 184hp in the Mazda 6. General Motors Quad4 2.3L 4 cylinder engine from 1992 made the same amount of power (aside from being a complete piece of shit) from less displacement. Take a look at the lift/duration profiles of the cams, compare to the Skyactiv.

Tripling the size of the intake leaves the airflow determined by camshaft design and cylinder displacement only. And the current setup likely has that taken into consideration as the manifold and intake are able to feed the necessary CFM. Changing the size will make no difference.

Significant power can only be yielded by an engineering change.

The end.
 

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Opinion? What opinion...

An opinion is subjective.

I am just sharing factual information here, and it was proven. Just trying to help here.

Now...how you use that information, to beleive or act upon it or not and what you think about it...it is all up to you.

Whatever it is....makes no difference to me.
Data is data, how you COMPREHEND it is what makes all the difference in what you believe and how you act on it. Everyone knows/understands that with more airflow of a K&N more things you don't want in your engine may make their way into the engine. If and how much that actually affects engine life is another story.

I've had a K&N on my 2003 Mazda6 almost since day one. Well over 10 years and 120,000 miles. She's doing just fine in the engine department. You know why? Because I CHANGE MY OIL from time to time and the minute/microscopic amount of extra dirt that makes its way through the K&N says bye bye with the old filter.
 
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Sideways the Seven
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