Would a K&N filter improve MPG or not advised

 

K&N is an excellent choice. For the investment of never needing to buy another air filter. s for improved MPG it very subjective. I have run K&N Filters for years, and if I can fit one to my intake systems whatever on anything that can use them, I have and do.
Should any comments from other members be made in other then a positive comment about K&N air filters I refer them to the K&N air filter Challenge. Buck stops there for a product line and its attributes!

 

Improved mpg from a high flow air filter relates back to pre-1980s carbureted engines without electronic controls. In olden days a high resistance air filter could cause the engine to run with a rich air-fuel mixture, thus wasting gasoline. A high flow filter had less of that potential problem. Modern electronically controlled engines measure the actual air flow (the mass air flow sensor) and decide how much fuel to use to get a precise mixture. A restrictive air filter now will give the same action as a throttle butterfly that won't quite fully open...you'll have some limitations at max horsepower, but that's it. The throttle has its job of restricting air flow to give you the power you want at any moment. A restrictive air filter just adds to that.

 

Pretty accurate..... but the term "OLDEN DAYS" now that's funny truly... made me

I trust when you say high resistance air filter you mean a dirty one. LOL Not sure if I ever actually saw any new ones that were manufactured to reduce flow? Back pre-80's most would be using American Manufactured replacement filters like Delco, Fram, Wix maybe a few others I would have to really think I mean that a long time back..... LOL My point is I do not recall "generic" air filters manufactured from China back then!

There is more to the ECU getting information form several sensors that regulate how the timing and fueling will be. Let's define a restrictive filter a little more with how captive elements leads to the reduction in total flow which really effects WOT and not as much normal driving city and highway speeds. A really dirty air filter can affect the MPG which is normally for the driver awareness then the reduced torque of the engine. Maybe a better discerption of a Throttle bodies task is the control of the air charge and not the restricting of air?

I have read many Data Logging from customers regarding ECU/EFI Calibrating have never seen a OEM or aftermarket air filter change any engine operation from the ECC/PCM/TCM from either factory operations or ones that *I had calibrated. On *Dyno Testing I can say that at WOT most stock or replacement air filters in a factory air filter housing did produce pretty equally TQ and HP results over many aftermarkets so called CAI without the hood open and a fan blowing over the engine produce any increases worth mentioning.

 

Well...the way the throttle assembly controls the air charge is how fully the butterfly opens. The butterfly is the circular disc with the pivot through its middle. Step all the way on the accelerator pedal and the disc pivots to allow the maximum airflow to the engine. Step part way down on the accelerator pedal and the butterfly pivots to partly closed to, well, throttle the flow of air into the engine. Take your foot off the accelerator pedal and the butterfly closes, and another passage allows enough air to the engine for idle speed. The mass airflow sensor and other gizmos measure the quantity of air being sucked into the engine (or pulled in by the turbocharger) and determines how much gasoline to inject for the correct air-fuel ratio for the engine's operation. The turbocharger is a gas turbine powered by hot exhaust gas that is on the same shaft as a centrifugal air compressor. The greater the heat and volume of the exhaust gas the faster the turbocharger will spin. It'll try to pump more air into the engine but that is, um, restricted by the throttle. (This is for an Otto cycle engine, our usual gasoline engine with a spark plug. A Diesel cycle engine has no throttle. The turbocharger pumps in all the air it can, and the injectors, controlled by the accelerator pedal or governor determine the fuel rate and power output. Nicolaus Otto lived from 1832 to 1891. Rudolph Diesel lived from 1858 to 1913. The last diesel engine I worked on was a straight 12 cylinder 2-stroke Sulzer that put out 57,500 hp at 95 rpm, direct drive to the propeller and reversible; it weighed 1700 tons and was 3 stories tall with about a 3' bore and 10' stroke. It was interesting.)

 

LOL not exactly accurate.... ^^^^^^ or even complete, and I read at least 1 wrong part of the information. At least if we are still talking about Mazda engine and predominately Skyactiv but it also would fall in line with even some older ones dating back to maybe 2000? LOL

Maybe some members should do some Data logging of the fuel system on any OBDII ECU/PCM and then make a technical write up that would be a little more accurate.?

Or hey maybe machine up their own Throttle body for a DI gas engine to increase CFM effecting what the sensors send to the ECU/PCM which changes among many things like timing, fueling even radiator fan controls on some models to name a few things... LOL

Or how about a BWD, if you don't know what that is then maybe start at the basics about inductive systems, ECU fueling control and then forced inductive systems before talking about the intricacies of Turbocharging or Supercharging a gasoline engine? LOL

Now I wonder why Throttle position % is an important monitoring value that I place and look at every time I drive my Mazda? LOL

Of the over 105 PID I can choose to continually monitor these as t I deem as the most important for me. They give me valuable information that can help me adjust my ECU calibrations, increase fuel efficiency, and watch for possible issues that me be starting.

Just took these after doing an errand, I think if anyone understood them, they would see and know that statement is accurate.
In my garage I let the engine idle and then increased the RPM for the pictures.

 

LOL I see you edited your response after I posted. LOL
I responded to your original that was sent to my email. When you subscribe to a thread you get the first version not the edited one usually.