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Air filter
- Thread starter BUZZ JR
- Start date
Air filters do NOT impact mileage. Power they can impact, but not mileage, unless totally and completely plugged.
Yep, in the old carburetor days the engine sucked the gas in along with the air so if it couldn't suck as much air the engine ran rich as it got less air and increased the suction on the gas. The same principle as a choke on most cars with carbs where a plate would block off a large portion of the intake causing the engine to run rich at start-up.
Modern fuel injected cars meter out the gas specifically to go with the amount of air that is coming in so less air ends up with matching less gas. This also helps them adjust to extreme altitude changes better.
Here's way more than I ever thought I'd want to read on the subject: http://www.fueleconomy.gov/feg/pdfs/Air_Filter_Effects_02_26_2009.pdf
Trevor
Mazda Accessories
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anybody have a k&n installed yet?
i'd like to see if there's any issues with them before i get one...
i used to have one in my old focus and my old fusion and in my dad's explorer...but my wife's car threw cel's since day one so we took it back out and sold it..
i'd like to see if there's any issues with them before i get one...
i used to have one in my old focus and my old fusion and in my dad's explorer...but my wife's car threw cel's since day one so we took it back out and sold it..
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The issue is that oiled cotton gauze filters have much less surface area (fewer pleats with a more coarse filter media) so they do not filter as well).anybody have a k&n installed yet?
i'd like to see if there's any issues with them before i get one...
i used to have one in my old focus and my old fusion and in ym dad's explorer...but my wife's car threw cel's since day one so we took it back out and sold it..
that's the point...
less surface area allows for more air flow..
that's why they have to be oiled to help colelct the dust and dirt particles that would normally get through it it was dry...(yes some will get through anyway but it's nto a huge deal)
if it bothers you that the inside of the engine is getting dirty don't get one...or doa fuel induction service cleaning to clean it all out...(like you should anyway about once a year or every ~15kmi-20kmi)
but tell me this...get a coffee stirrer(one of those thin straws...compare that to a paper filter) and get a regular straw(compare that to k&n)...wich one is easier to breathe through?
yes, i know the ecm will compensate to a certain extent, but the point is to increase the breathing efficiency of the engine by not having to make it suck as hard through the paper filter or the smaller exhaust(if you're replacing the exhaust)...
that's how intakes and exhausts increase power...better flow of air through the engine wich..
true, you'll get more power/efficiency after those AND a tune...but you'll still get greater efficiency over OE parts and NO tune
less surface area allows for more air flow..
that's why they have to be oiled to help colelct the dust and dirt particles that would normally get through it it was dry...(yes some will get through anyway but it's nto a huge deal)
if it bothers you that the inside of the engine is getting dirty don't get one...or doa fuel induction service cleaning to clean it all out...(like you should anyway about once a year or every ~15kmi-20kmi)
but tell me this...get a coffee stirrer(one of those thin straws...compare that to a paper filter) and get a regular straw(compare that to k&n)...wich one is easier to breathe through?
yes, i know the ecm will compensate to a certain extent, but the point is to increase the breathing efficiency of the engine by not having to make it suck as hard through the paper filter or the smaller exhaust(if you're replacing the exhaust)...
that's how intakes and exhausts increase power...better flow of air through the engine wich..
true, you'll get more power/efficiency after those AND a tune...but you'll still get greater efficiency over OE parts and NO tune
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but tell me this...get a coffee stirrer(one of those thin straws...compare that to a paper filter) and get a regular straw(compare that to k&n)...wich one is easier to breathe through?
That example doesn't work in the least for a comparison.
The opening that the filter fits into stays the same.
A square inch of filtering material has a specific amount of resistance to airflow.
If you just make it a flat section of that material you only get (just guessing here as I don't have the filter measurements, using 10x4 for a rough filter size) 40 square inches of surface area for the air to flow through with each square inch still having the same amount of resistance.
Now if you add pleats and you triple the surface area of the filter you now have 120 square inches of surface. With each inch of that surface having the same resistance to flow as the single inch.
You aren't increasing the resistance you are lowering it.
Say the car is sucking in 200 cubic feet per minute.
With the 40 square inch filter you are forcing 5 cubic feet of air per minute through each square inch of surface area.
With the pleated 120 square inch of surface area filter you are forcing 1.7 cubic feet of air per minute through each square inch of surface area.
In effect you have taken what was a 10" x 4" filter and made it into 10" x 12" (again, not the actual filter measurements just examples) So how can a filter that is 10" x 12" have more restriction than a 10" x 4" filter if the media is the same?
All filter media has some type of restriction to it so the goal is to increase the surface area that the air flows through.
Basically the opposite of your example. By pleating the filter they've gone from the coffee stirrer to the big straw.
More pleats equals more surface area. More surface area means less air that has to pass through each square inch of that surface at any given time. Less air being forced through the same space means less suction needed to accomplish it. More pleats equals more efficient air flow.
To sum it up, more pleats equals greater surface area which acts like a much larger filter than one with less pleats. And a larger filter (your example of the two straws again) is better.
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More pleats equals more surface area. More surface area means less air that has to pass through each square inch of that surface at any given time. Less air being forced through the same space means less suction needed to accomplish it. More pleats equals more efficient air flow.
more pleats equal more resistance to flow...that's what im getting at...
the k&n has FEWER pleats and also the cotton gauze has less inherent restriction than the paper media in the OE filter with MORE pleats...
if you've ever tried to suck air through a piece of paper(pleated ot not) and tried to suck air through a piece of cotton gauze(or cotton ball) you'll notice it's much easier to suck through the cotton...
that's the point...
less surface area allows for more air flow..
I don't want to discuss this with someone who can't grasp the concepts presented but, in the interest of having accurate information available to readers of this forum, I'll provide a few additional comments. First - It's a fact that, for any given filter media, more filter area = less resistance to flow. Whether this results in more flow or not depends upon whether the filter is the limiting factor in terms of how much an engine can flow. In engines like the 2.0L and 2.5L CX-5 (and most modern engines for that matter), the flow is limited primarily by the intake valves and intake geometry - the air box and filter is designed around that flow rate. That is why removing the air filter entirely in the vast majority of modern engines does not increase output.
While it's true that many oiled cotton filters have larger "pores" in the filter media, it's also true that drop in replacements for the OEM filters almost always have fewer pleats and often the pleats are also shallower in depth which further compounds the lack of surface area. The net result is often slightly more restriction. But even if you opt for replacing the air box entirely, with a barrel shaped gauze filter that actually does exceed the flow capabilities of the OEM paper filter, you are unlikely to gain any power. Again, the reason for this is as explained above - the intake valves and the intake tract immediately surrounding the valves is the limiting factor to flow.
that's why they have to be oiled to help colelct the dust and dirt particles that would normally get through it it was dry...(yes some will get through anyway but it's nto a huge deal)
I can't believe you said that!
Yes, fine abrasive road sand sucked past the intake valves is a HUGE net negative for the life of your engine. Your valve guides, piston rings and cylinder walls will take the brunt of the wear from these abrasives because the oil filter will eventually collect the abrasive fines after it makes it's way past these components but some of the abrasives will also make it to your main bearings, cams, etc. And once your oil filter is plugged the bypass will open and the abrasives are free to circulate unimpeded. You bet it's a big deal - that's why effective air filtration is so important to the life of any engine.
if it bothers you that the inside of the engine is getting dirty don't get one...or doa fuel induction service cleaning to clean it all out...(like you should anyway about once a year or every ~15kmi-20kmi)
Cleaning the intake periodically is not a solution - the fine road abrasives are inhaled in real time. It's worse on the freeway because traffic speed insures there is plenty of fine abrasives stirred up and your engine is gulping air at a much higher rate at higher rpm's and throttle openings. With the OEM paper filter media (properly seated) your intake tract will never need cleaning anyway - that's why this service procedure is not listed on the maintenance schedule.
but tell me this...get a coffee stirrer(one of those thin straws...compare that to a paper filter) and get a regular straw(compare that to k&n)...wich one is easier to breathe through?
The bigger straw is easier to breath through but only because the straw is the limiting factor (compare the straws diameter to the size of your throat).
Bottom line, no performance increase but more abrasive matter in your engine. Test after test confirms this - do not fall for the claims of the aftermarket manufacturers. Those claims (and a gullible public) are the primary tool they have to sell their product.
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more pleats equal more resistance to flow...that's what im getting at...
the k&n has FEWER pleats and also the cotton gauze has less inherent restriction than the paper media in the OE filter with MORE pleats...
if you've ever tried to suck air through a piece of paper(pleated ot not) and tried to suck air through a piece of cotton gauze(or cotton ball) you'll notice it's much easier to suck through the cotton...
You are arguing with the laws of physics and you have two different arguments there!
I didn't mention anything about paper vs gauze for what flows better.
The fact remains that more pleats equals larger surface area and so less air being forced through the same space at the same time and thus better air flow when it is the same material.
Have someone read my prior post, about surface area, to you.
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- Mazdaspeed6
Not to mention, and from my own experience, over oiled or improperly oiled filters (which is easy to do) can leak past the filter element and enter the intake tract.
Really not a huge deal for the engine, as the oil will just combust, but if it collects on the MAF sensor, it can cause some issues. I have had this occur on two previous vehicles on which I ran oiled filters, and it was a problem on both.
I just stick with dry elements now.
Really not a huge deal for the engine, as the oil will just combust, but if it collects on the MAF sensor, it can cause some issues. I have had this occur on two previous vehicles on which I ran oiled filters, and it was a problem on both.
I just stick with dry elements now.
apexanimal
Member
- :
- 2013 CX5 Sport, 6mt
There are dryflow filters that are non oiled, and flow just as well as the k&n, but filter far better...
Do your research...
Do your research...
The air filter on the CX-5 is not the point of restriction. I would be interested in such a filter for it's better filtration (if it really is more effective than a pleated paper media filter) but increasing flow capability will not increase performance for the reason already explained multiple times. If more flow would increase performance we could get more performance simply by removing the air filter.There are dryflow filters that are non oiled, and flow just as well as the k&n, but filter far better...
Do your research...
BTW, please provide a link to this more effective filter for our CX-5. I have not been able to find one but am interested (if true).
apexanimal
Member
- :
- 2013 CX5 Sport, 6mt
Like most things I come across, I can't dig it back up and don't want to spend my time looking for it... So take it as you will.
The air filter won't be the biggest restriction, but it certainly is one... You'd have to get one of dryers magnehelic gauges in the 20-30" of water range and put probes before and after each transition and bend in the intake system... But to say that the filter isn't a restriction isn't true - albeit it's a small one and time/money IMHO is better spent elsewhere...
Autospeed has done quite a few of these tests, and do say repeatedly that the filter is not the largest restriction, but is typically the "easiest" to change (just swap out a filter)... Most of the restriction comes from a small snorkel, poorly placed inlet (in a low-pressure area), and a restrictive airbox to tb pipe...
I've almost always kept the stock box (making a new box isn't something I'm excited about doing) and reworking the box to tb pipe, snorkel, and placing the inlet in the best high-pressure spot on the front of the car... It does yield noticeable results.
The air filter won't be the biggest restriction, but it certainly is one... You'd have to get one of dryers magnehelic gauges in the 20-30" of water range and put probes before and after each transition and bend in the intake system... But to say that the filter isn't a restriction isn't true - albeit it's a small one and time/money IMHO is better spent elsewhere...
Autospeed has done quite a few of these tests, and do say repeatedly that the filter is not the largest restriction, but is typically the "easiest" to change (just swap out a filter)... Most of the restriction comes from a small snorkel, poorly placed inlet (in a low-pressure area), and a restrictive airbox to tb pipe...
I've almost always kept the stock box (making a new box isn't something I'm excited about doing) and reworking the box to tb pipe, snorkel, and placing the inlet in the best high-pressure spot on the front of the car... It does yield noticeable results.
http://cars.about.com/od/productreviews/fr/ag_knfilter.htm
http://www.nicoclub.com/archives/kn-vs-oem-filter.html
http://www.knfilters.com/faq.htm
if you read the info and see the graphs on the 2nd link they directly show that the k&n filter has superior flowing ablity compared to the multiple OEM and OEM style filters...yes if can allow more small particles of dust and dirt through compared to the OEM or OEM style
but like the 1st link states, an engine builder can't see a big enough difference if you stay on top of PROPERLY MAINTAINING(cleaning and oiling...did i say properly?) your filter as needed...no matter what kind
link 3...and if you look on the K&N website it clearly states how to properly clean and oil your filter so it doesnt cause misreading from your intake sensors(so it clearly state in the cleaning instructions included in your cleaning kit)
a pleated filter does not increase airflow, it increases surface area for flowing dirt to collect in, therefore increasing the service interval but reducing flow(by the nature of being paper vs cotton) and having smaller pores for the air to go through
http://www.nicoclub.com/archives/kn-vs-oem-filter.html
http://www.knfilters.com/faq.htm
if you read the info and see the graphs on the 2nd link they directly show that the k&n filter has superior flowing ablity compared to the multiple OEM and OEM style filters...yes if can allow more small particles of dust and dirt through compared to the OEM or OEM style
but like the 1st link states, an engine builder can't see a big enough difference if you stay on top of PROPERLY MAINTAINING(cleaning and oiling...did i say properly?) your filter as needed...no matter what kind
link 3...and if you look on the K&N website it clearly states how to properly clean and oil your filter so it doesnt cause misreading from your intake sensors(so it clearly state in the cleaning instructions included in your cleaning kit)
a pleated filter does not increase airflow, it increases surface area for flowing dirt to collect in, therefore increasing the service interval but reducing flow(by the nature of being paper vs cotton) and having smaller pores for the air to go through
a pleated filter does not increase airflow, it increases surface area for flowing dirt to collect in, therefore increasing the service interval but reducing flow(by the nature of being paper vs cotton) and having smaller pores for the air to go through
you are almost there.... the K&N flowing more has nothing to do with the pleats and everything to do with the filtering material.
Otherwise a larger air filter wouldn't be a better flowing filter and even K&N says larger is better:
"Typhoon Air Intake System: They come with an oversized High-Flow conical air filter designed to provide increased surface area and dust capacity. This extra surface area provides even more airflow at lower restriction than a standard K&N O/E replacement filter that is limited to the size of the factory air box."
http://www.knfilters.com/cold_air_intakes.htm
^yes, that's true, but they're comparing a k&n cone filter to a k&n drop-in filter...(typhoon is their brand of cold air system)
the pleating is what mike m. has been talking about...and the filtering material is what i've been talking about...
the point is like multiple places say and what i've been saying...a k&n(drop-in filter) will allow the engine to have a easier time(less restriction in the same space occupied by the OE filter) sucking air(the same ammount, as restricted by the stock pipinggoing INTO the airbox) through the OE airbox(same restriction of the system)...
and the pleats in the filter deal with the ammount of dirt the filter will collect(service life), not airflow capacity or ability(doesn't matter wether it's paper or cotton) as compared to a flat filter
the oiling issues are an entirely different concern(since it doesn't restrict, nor ease airflow) it is because most people over-oil and/or don't let the oil soak in properly or have the excess run off like instructed...so the excess oil gets sucked into the engine coating the maf, causing driveability concerns and an engine light, etc etc etc
the pleating is what mike m. has been talking about...and the filtering material is what i've been talking about...
the point is like multiple places say and what i've been saying...a k&n(drop-in filter) will allow the engine to have a easier time(less restriction in the same space occupied by the OE filter) sucking air(the same ammount, as restricted by the stock pipinggoing INTO the airbox) through the OE airbox(same restriction of the system)...
and the pleats in the filter deal with the ammount of dirt the filter will collect(service life), not airflow capacity or ability(doesn't matter wether it's paper or cotton) as compared to a flat filter
the oiling issues are an entirely different concern(since it doesn't restrict, nor ease airflow) it is because most people over-oil and/or don't let the oil soak in properly or have the excess run off like instructed...so the excess oil gets sucked into the engine coating the maf, causing driveability concerns and an engine light, etc etc etc
the pleating is what mike m. has been talking about...and the filtering material is what i've been talking about...
except for:
more pleats equal more resistance to flow...