Is this normal for a standard air filter?

[TXGREEK]

If your BMW (and presumably Porsche) is anything like mine, it has carbon in the cabin filter.  Just a filter itself isn't going to block a smell, the molecules causing the smell are too small to be captured by a filtration media alone... you can smell something rotting inside a ziplock back, can't ya?  Carbon infused into the filter is necessary to block the scent; I know the cabin filter I replaced in my truck didn't have any.

GM needs to step up and get with the times, news reported pollution is getting worse outside. Even the recirculation button doesn’t shut off the outside air from coming in. Moving on.....


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[mitchely03]

I worked at K&N in Riverside, CA for a couple years as a tech. Absolutely no possible way a modern engine can pull the oil off of the filter and coat the MAF.

 

You would be 2 thousand plus horsepower at minimum to do something like that, and if youre running that much power, then you dont need a filter because that car is a drag race car.

 

I would get consistent calls and i would invite people down constantly so I can show them whats up. 

 

I dont work there anymore for personal reasons, but i still enjoy the product with no issues. If there was a problem I dont think would be in business anymore after this many years.

[rbrjr1]

On 8/26/2019 at 12:27 AM, dukedkt442 said:

And how many miles did you take those engines with no issues? Run compression tests at beginning and end? Any oil wets the maf. Because physics. Flow rate and filtration are inverses. Because physics. My 20 years of dealing with them shows them to be junk. But whatever...who cares about getting over 200k with no oil loss, these trucks get tossed long before that. Long live bragging rights and back window stickers!

well.. the last truck I owned (Tahoe 5.7L actually) finally kicked it at (12 years) 275,000mi.  I bought it at 21,700mi and literally drove from the dealership to the auto parts store to pick up my K&N filter.. (but that was 20 years ago, maybe the engines are far more susceptible to air intake impurities now)

Edited August 28, 2019 by rbrjr1

[Nanotech Environmental]

Caution- this post may cause some ruffled feathers LOL.

(you've been warned)  

IMO most people worry waaay too much about air filters. What's important is what the engine side of the filter looks like & the integrity of the intake tract. If the filter is a good filter & backside of the filter is clean and the intake tract is sealed & spotless, all is good.

As filters get dirty, they become better at trapping more and more dirt, finer and finer. They actually get more efficient at cleaning the air as they get dirtier. (Even K&N filters which aren't much better than a screen door.)
Eventually they lose ability to flow as this happens. However, in most vehicles, the filter has to get very dirty before it can affect engine performance.
Very dirty. Very, very dirty.
It literally has to have dirt heaped on it before it chokes the engine.
There is a lot of excess filter surface area on folded paper filters, as well as oiled foam elements used in other applications. This surface area ensures the filter flows more than adequate air even when the filter is 'dirty'- ie. fully covered in visible dirt.

On a 4t engine, the air only goes thru the valves and stays above the piston. It doesn't affect the engine as much as many think it does.

2t engines are much more sensitive to clean air. On a 2t engine the air goes thru both the bottom end and the top end. The air gets to the crank bearings, rod bearings, wrist pin, cylinder, piston. etc. 

Here's some counter intuitive thinking; My thoughts are that those that change filters often are (very possibly) actually causing more harm than good;

Each time you change a filter, you risk allowing stray bits of dirt into the intake. This is waaay worse than leaving the filter in for a much longer time.

IMO, You're better off installing a good filter, then when there's heavy visible dirt on the filter, pop the air cleaner cover off and vacuum the dirt off the filter, while leaving the filter in place. Don't disturb the sealing surface where the filter is mounted. Then do this again xx,000 miles later... & again & again.

I've learned this from the dirtbike world, where filters get dirty fast & the engines are run hard. I ride a 250cc 2 stroke, primarily in the woods. 
I only change my air filter out once a year or so, or about every 80-100 hours. During the season, I occasionally vacuum off the heavy stuff and add more oil to the filter, while leaving the AF installed.
This keeps the intake tract spotless and uncompromised.
When I do change out the filter, I actually carefully remove the whole airbox and seal the carb.
Once the airbox is free from the bike, I'll remove the old filter, totally & thoroughly clean the airbox and install a new filter.
 

Here are some pics from the last AF change out:
 

Extremely dirty filter and airbox 250cc 2 stroke dirtbike (yes, there's an airfilter in there LOL):

Clean air filter backside and intake tract (tiny specs of dirt in intake tract are from when I removed the filter).

See how dirty the airbox and filter are? The filter looks horrible, yet still flowed more than
enough air to allow the engine to easily come on the pipe at will, with no loss of performance.. 
Most important is that the AF is doing its job well & everything, including the sealing surface maintained its integrity.
 

My approach drives the conventional thinkers mad.. However........
 

Does it work?

Yes. Here is the factory piston out of this same bike. It has 217 hrs on it. 250cc 2 stroke.
I could have easily left this in for another 200+ hours. Ring gaps still at factory spec. The
bike now has about 400 hrs on it. 2nd piston. Still at over 180 psi compression. Still on
original bottom end.



Most offroad guys I know with 250 2 strokes are rebuilding about every 80-120 hrs. They are also
changing their air filters all the time, because they have been told to.

IMO, on these GM trucks, if you're only driving on paved roads in mostly urban areas, the air filter
will be good for a very long time. For many they can go 80-100k miles, with no issues.

Who's right? All I know is that this is what works for me.

Edited August 28, 2019 by Nanotech Environmental

[Mozzer]

Thanks for all the input, I have ordered an AEM dryflow.

As for the K & N debate I have used them in competition cars, my thoughts then were they wouldn't fall to bits if they got wet & get sucked into the engine.

No idea if they were any better at keeping water out but I didn't ever die after a water splash, although I wasn't brave enough to go through flat out, rather lose half a second on a stage than than lose the engine.


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[camcamaro1991]

On 8/27/2019 at 9:20 AM, TXGREEK said:

 

GM needs to step up and get with the times, news reported pollution is getting worse outside. Even the recirculation button doesn’t shut off the outside air from coming in. Moving on.....


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GM is with the times, foolish statement.

 

Manufactures don't fully close, due to CO - Carbon Monoxide & CO2 Carbon Dioxide levels. Older vehicles that would close all the way caused people to pass out while driving, they noticed a trend more often in colder climates when using the heater, the full closing of the air resulted in death, and sometimes due to accident as in loss of control of the vehicle, hence why NO manufacture closes them all the way unless it some type of engineering defect like a more recent example the ford police SUV's. 

 

[TXGREEK]

GM is with the times, foolish statement.
 
Manufactures don't fully close, due to CO - Carbon Monoxide & CO2 Carbon Dioxide levels. Older vehicles that would close all the way caused people to pass out while driving, they noticed a trend more often in colder climates when using the heater, the full closing of the air resulted in death, and sometimes due to accident as in loss of control of the vehicle, hence why NO manufacture closes them all the way unless it some type of engineering defect like a more recent example the ford police SUV's. 
 


If you’ve lived it then you’d understand.

Cabin exhaust vents are in most European model vehicles, all my land cruisers even had some sort of air vacuum sound in the rear, BMW, Mercedes, Range Rover and Porsche have excellent recirculated air, you literally smell nothing but what a recirculating cabin smells like. Recently drove a Raptor for a weekend and smelled nothing of the outdoors. It’s not that it should be closed off in a way for no fresh air to come in but there’s got to be a much better system made. What does recirculating mean to most people.

Last year I drove my Yukon XL to the Grand Canyon loaded with kids only having to get out because a horrible outdoor skunk scent dwindled inside the cabin for hours and when we did get out, the outside air was much cleaner than the inside “recirculating air.”

I love my truck but the recirculating air is very below average.


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[rbrjr1]

38 minutes ago, camcamaro1991 said:

GM is with the times, foolish statement.

 

Manufactures don't fully close, due to CO - Carbon Monoxide & CO2 Carbon Dioxide levels. Older vehicles that would close all the way caused people to pass out while driving, they noticed a trend more often in colder climates when using the heater, the full closing of the air resulted in death, and sometimes due to accident as in loss of control of the vehicle, hence why NO manufacture closes them all the way unless it some type of engineering defect like a more recent example the ford police SUV's. 

 

CO is not an issue on a vehicle with a catalytic converter, assuming there isn't an exhaust leak upstream of the converter.

[Grumpy Bear]

4 hours ago, Nanotech Environmental said:

Caution- this post may cause some ruffled feathers LOL.

(you've been warned)  

IMO most people worry waaay too much about air filters. What's important is what the engine side of the filter looks like & the integrity of the intake tract. If the filter is a good filter & backside of the filter is clean and the intake tract is sealed & spotless, all is good.

As filters get dirty, they become better at trapping more and more dirt, finer and finer. They actually get more efficient at cleaning the air as they get dirtier. (Even K&N filters which aren't much better than a screen door.)

Eventually they lose ability to flow as this happens. However, in most vehicles, the filter has to get very dirty before it can affect engine performance.Very dirty. Very, very dirty.

There is a lot of excess filter surface area on folded paper filters, as well as oiled foam elements used in other applications. This surface area ensures the filter flows more than adequate air even when the filter is 'dirty'- ie. fully covered in visible dirt.

 

IMO, You're better off installing a good filter, then when there's heavy visible dirt on the filter, pop the air cleaner cover off and vacuum the dirt off the filter, while leaving the filter in place. Don't disturb the sealing surface where the filter is mounted. Then do this again xx,000 miles later... & again & again.

 

My approach drives the conventional thinkers mad.. However........
 

Does it work?
 

Who's right? All I know is that this is what works for me.

Were you expecting me? 

 

Well argued, well written. Insightful. 

 

I do however have a few questions. Earlier a member posted a TSB from Ford showing filter performance as a root cause for misfires in that it altered the signal seen by the MAF. The filter test offered also referenced the mass air flow to a specific inlet frequency. I assume your bike is carbureted.

 

                                     Thoughts on filter condition Vs MAF signal please.

 

Okay no questions. I beg your opinion.  

Edited August 28, 2019 by Grumpy Bear

[Nanotech Environmental]

5 minutes ago, Grumpy Bear said:

Were you expecting me? 

 

Well argued, well written. Insightful. 

 

I do however have a few questions. Earlier a member posted a TSB from Ford showing filter performance as a root cause for misfires in that it altered the signal seen by the MAF. The filter test offered also referenced the mass air flow to a specific inlet frequency. I assume you bike is carbureted. Thoughts on filter condition Vs MAF signal please. Okay no questions. I beg your opinion.  

Actually, believe it or not, I didn't have you in mind when I wrote that.

My bike is carbureted with a 'SmartCarb', which relies heavily on the air signal. Probably as close to fuel injection as you can get without fuel injection. It's a very clever design. No jets, no overflows & only 2 adjustments; idle and mixture. 

I could see it possibly causing a MAF signal issue on some vehicles if the filter is really clogged. It would take a lot for that to happen though, assuming stock filter is being used.... However, given how many aftermarket 'Cold air intakes' there are out there & that they typically use smaller (than stock) filter elements, I wouldn't be surprised if that is playing a role as well......?

Also, there is a good sized %age of the pop. that has no idea what an air filter is, or that it needs to be changed or cleaned at some point: Vehicle isn't running right and tech finds the air filter loaded with 3" of dirt......... LOL That could play a role.

[DESERT DOG]

Found this looking for information  on K&N's a while ago. Pretty interesting. It's from a different forum,  so not really sure if I should post it or not but here it is.

https://nicoclub.com/archives/kn-vs-oem-filter.html

[Grumpy Bear]

2 hours ago, DESERT DOG said:

Found this looking for information  on K&N's a while ago. Pretty interesting. It's from a different forum,  so not really sure if I should post it or not but here it is.

https://nicoclub.com/archives/kn-vs-oem-filter.html

This was the test I was actually looking for when I posted the previous link. Thanks! 

 

All said and done I'll continue to use the AC Delco OEM filters and change on about 25K OCI. 

[rbrjr1]

A new MAF is about $60 online.

 

why not just replace it every year since you're "saving" so much not buying pleated paper filters any longer... ?

[16LT4]

9 hours ago, Grumpy Bear said:

This was the test I was actually looking for when I posted the previous link. Thanks! 

 

All said and done I'll continue to use the AC Delco OEM filters and change on about 25K OCI. 

And I'll continue recommend against K&Nope!

[diyer2]

I put K&N's in all my vehicles first thing.

Never had a problem and I keep them for a long time.

 

This is just like the motor oil debate.

Do what makes you happy.