When you hold the air filter up to the light and cannot see light through the filter, the filter is dirty. Here where I drive in Colorado and WY it's dry and dusty. So I change the filter more often. Someone who lives in Hawaii might never change their filter. You really should try one of these K&N filters

 

Clearly you are wedded to your K&N as there is very little anyone can say about just how much of a scam they are. I'll try it one more time and then let it go.

Send your oil out for analysis and look at the silicone (i.e. sand) numbers, then put in a factory air cleaner, drive for a few oil change cycles, and then send your oil out again. What you will discover is the silicone numbers will drop dramatically.

As for frequent filter changes, that pretty much defeats the purpose, the fact is, with any sieve type of filter, as it ages its filtering efficiency will improve. Said another way, a clean filter will let in far more and far larger dirt particles than a dirty filter.

 

Interesting thread. I'd add a different wrinkle...
On my 2007 Mazda6, I tried Stock Air filter, Stock Air Filter with modified air box, AEM ShortRam Intake, and Sure Motorsports ShortRam Intake.
In my real-life experience with these I can attest to the following:

The Stock filter was good, the car ran well with it, nothing special.

Modifying the Air Box created a bit more flow, more noise, and that was about it.

The AEM Short Ram increased the Low-End torque, and did increase the air flow, and did increase fuel mileage approximately 3 MPG. The Drawback was the need to clean the mass airflow sensor every couple of months. The air is indeed dirtier with the AEM.

The Sure Motorsports Short ram was very similar in performance to the AEM except that through tuning the airflow within the intake itself, the power-band was increased to 1800 - 4000 RPM. Sure used a different type of filter media and also offered a pre-filter for their intake which greatly reduced the dirt on the mass airflow sensor.

Take it for what you will, these are my real life findings both on the street, on the strip, and on the dyno.

Now as for the CX5, I contacted Sure, and they state that since the Sky-active is factory tuned, there isn't much to be done to this vehicle.
That said, the mileage on my vehicle is abhorrent, the dealer continually states that I need to reset the trip and mileage computers even though I am determining my mileage the old fashioned way using math, running the tank to nothing, and tracking the amount of fuel that I put into the vehicle. No resetting needed, the Mileage 18-21 MPG average, 26 MPG highway @ 70MPH is awful!

 

Okay, since such claims keep being made, I have to ask; by what mechanism do you believe the SRI improved your fuel economy? If you have figured it out, automobile manufacturers from all over the world will be beating a path to your door for the secret.

 

Simple math my friend, simple math...
One tankful stock get x miles per gallon
next tankful SRI, X +3 miles per gallon

Dyno before SRI x horsepower
Dyno after SRI X+ horsepower

In fact Mazda dealers do sell alternative intakes.

I'm not advocating anything, simply reporting my results...

 

There is no way you can drive consistently enough to show results worth analyzing; as such, what you say is purely anecdotal.

That said, the science/physics of what you claim are impossible; if you understood how modern fuel injection systems worked you'd understand that.

 

Again, simply reporting results...

Make of them what you wish...

 

I suspect if you were to take that SRI off and put the factory intake back on you'd get the same mileage as when you had the SRI on. The fact is, there is nothing in an intake which can alter the air to fuel ratio as that is calculated after the air has already left the intake and passed through the throttle body.

Like I wrote before, if you understood how a modern fuel injection system worked, you would know your anecdotal evidence was incorrect.

 

Hmm... " if you understood how a modern fuel injection system worked, you would know your anecdotal evidence was incorrect."

I'm not sure that I understand, help me out as I'm obviously not as intelligent as you, (Engineer correct?)
So If something happens in real life, that multiple people are reporting has happened all over the globe, and that result doesn't fit with your "trained opinion" on paper in your computer or how you know that modern fuel injection works, then it obviously never happened because it couldn't happen?

Just checking...

BTW Which Mazda are you driving ?

 

There are anecdotal reports from all over the world about miracle fixes, cures, applications, herbs, you name it, they're out there.

So, let's back up a bit, I suggest you check out the AEM Induction Systems web site; per their own claims, depending upon the product they make the following claims:

• Designed to Increase Horsepower
• Estimated HP(?) (then some arbitrary value depending upon the vehicle)

So I have to ask you this, do you *really* believe AEM wouldn't be plastering that fact all over their web site in huge blinking bold letters if their product improved fuel economy by well over 10% (your claim)?

The fact is, simply changing the intake cannot do what you claim, so either your driving changed or your fuel economy gains didn't happen (I suppose you could make the argument your engine finally finished the break in process, but that's a long shot). The one thing which is certain is the SRI you have on your car is not responsible for any change in fuel economy.

As for your questions, yes, I'm an engineer, and I've worked in that capacity for three different manufacturers (Chrysler, Mercedes-Benz, and Volvo). As for the Mazda I drive; we are currently without one. That said, I had a sweet little 2009 Mazda3 which I sent off to college with my son (he is now in his second Miata, a very nice 1996 M Edition), and per my signature, my wife and I just ordered a 2016 Mazda3 s GT 5-Door with three pedals under the dash; it should be here any day now.