What Air Filter?

[PNW EXPLR]

I did a recent trip with a buddy. We dis about 100 miles on a very dusty forest road system. I spent most of the time following.
My air filter was packed with dust so I beat it out to get home then bought a new Wix filter for 40 bucks. This could get really expensive.
I know there are tons of reusable filters. And a lot of pros and cons for each one.
What are you using?

 

[MazeVX]

Always used K&N, never had any problems.
In case you are doing this more often, I would suggest a snorkel with a pre filter or cyclone filter.

 

[Tim]

I use a Uni Filter, it’s an washable foam filter but when travelling in really dusty conditions I use an OEM paper filter. You can’t knock the dust out of an oiled filter so easily so I keep that for highway use.
As posted above a snorkel with a cyclonic head helps. Again I use that in dusty conditions and keep the standard ram head on otherwise. Just my thoughts.

 

[PNW EXPLR]

Always used K&N, never had any problems.
In case you are doing this more often, I would suggest a snorkel with a pre filter or cyclone filter.

I have used K&Ns in the past. Then I started hearing poor reviews. Like dust was getting by the filter.
I have been thinking about a snorkel for a while. I need to see what my options are. I do like the look of the AEV setup.

 

[PNW EXPLR]

I use a Uni Filter, it’s an washable foam filter but when travelling in really dusty conditions I use an OEM paper filter. You can’t knock the dust out of an oiled filter so easily so I keep that for highway use.
As posted above a snorkel with a cyclonic head helps. Again I use that in dusty conditions and keep the standard ram head on otherwise. Just my thoughts.

Thinking this is the way to go. Maybe even carry a spare washable. Used to do this for my dirtbikes.

 

[smritte]

I only use paper filters. Go read independent air filter testing. You will be surprised. If you really want to see the difference, install one of these after your filter Air Filter Service Gauge. I installed it in my jeep and cruiser. Did hard accelerating with no air cleaner. That was my base line. Installed an AC Delco paper air cleaner because they have the best filtering for the powder I have out here. The gauge came down slightly and I didn't notice any real power difference. Every now and then, I would pull the filter and smack it on the ground to knock the dirt off it. I finally changed it after almost 2 years because I damaged it when I hit it on the ground.

I put the gauge in after reading how the air cleaner is the most over replaced part on your vehicle. If I'm driving in a group, I normally take the rear. That means more dust. I also send out a sample of my oil to Blackstone labs once a year. When I ran a K&N on my TJ, the report showed a high amount of silica. That's the dust that the K&N let through (Properly oiled). Problem went away with paper filters.

Do the research on air and oil filters. None of them are the same.

 

[Desert Runner]

I only use paper filters. Go read independent air filter testing. You will be surprised. If you really want to see the difference, install one of these after your filter Air Filter Service Gauge. I installed it in my jeep and cruiser. Did hard accelerating with no air cleaner. That was my base line. Installed an AC Delco paper air cleaner because they have the best filtering for the powder I have out here. The gauge came down slightly and I didn't notice any real power difference. Every now and then, I would pull the filter and smack it on the ground to knock the dirt off it. I finally changed it after almost 2 years because I damaged it when I hit it on the ground.

I put the gauge in after reading how the air cleaner is the most over replaced part on your vehicle. If I'm driving in a group, I normally take the rear. That means more dust. I also send out a sample of my oil to Blackstone labs once a year. When I ran a K&N on my TJ, the report showed a high amount of silica. That's the dust that the K&N let through (Properly oiled). Problem went away with paper filters.

Do the research on air and oil filters. None of them are the same.

What you wrote is so correct. Paper......quality.... paper filter elements, do indeed have the best filtration for fine dust particles on any vehicle that sees mixed or off-road use. Save the K&N, or even the ...OMNI UNI foam for the street vehicles. Because if you have a turbocharger, the suction will pull the oil off the filter and onto the MAP wire in the throttle body, causing performance issues. In the end, Paper=best, Foam=next. A K&N, even with the pre-filter cover, is only marginal. Use just the gauze, and your asking for trouble in the long term. The 'Diesel Place' forum, did a exhaustive test and evaluation over 10 years ago. If you can locate it, it makes for a fascinating read. They tested in excess of 15-20 different brands, types, and were surprised themselves on the results documented thru a independent lab.

As you also stated, paper can be used/cleaned over and over. Andrew St. Pierre White , of 4x Overland did a piece on dust build-up in snorkeled trucks, as a everyday necessity to clean when in convoy, or heavy dust from wind etc. The amount knocked off each morning was sobering. He did a You-Tube article on it.

EDIT:
UNI does make a oiled foam snorkel inlet cover to pre-filter dirty air at the snorkel inlet. Seen them offered on E-Bay, and some Australian web-sites. I also think Micheal of 'Seek Adventure' made a passing reference to using one also (standard inlet, not conical type), with the caveat of not for highway use (high speed driving', only low speed/lower RPM use. But don't quote me on that !

I think I saw a OB-video where OB #0000, used a UNI red snorkel pre-filter on the Land Cruiser also

 

[TerryD]

AC Delco

Check out this article I post every time someone asks.

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

Before spending your money on an aftermarket intake, let's debunk the misleading incomplete info about filtering and horsepower in the sales literature.

nicoclub.com

 

[Cort]

Another vote for OEM filters. Don’t buy into the hype and wizardry of the aftermarket.

Unless you are creating massive power over stock or doing desert racing stock is more than acceptable.

 

[PNW EXPLR]

I only use paper filters. Go read independent air filter testing. You will be surprised. If you really want to see the difference, install one of these after your filter Air Filter Service Gauge. I installed it in my jeep and cruiser. Did hard accelerating with no air cleaner. That was my base line. Installed an AC Delco paper air cleaner because they have the best filtering for the powder I have out here. The gauge came down slightly and I didn't notice any real power difference. Every now and then, I would pull the filter and smack it on the ground to knock the dirt off it. I finally changed it after almost 2 years because I damaged it when I hit it on the ground.

I put the gauge in after reading how the air cleaner is the most over replaced part on your vehicle. If I'm driving in a group, I normally take the rear. That means more dust. I also send out a sample of my oil to Blackstone labs once a year. When I ran a K&N on my TJ, the report showed a high amount of silica. That's the dust that the K&N let through (Properly oiled). Problem went away with paper filters.

Do the research on air and oil filters. None of them are the same.

My old Chevy avalanche had one of those gauges from the factory. I totally forgot about them. Gunna order one from Amazon today. Thanks for the reminder.

What you wrote is so correct. Paper......quality.... paper filter elements, do indeed have the best filtration for fine dust particles on any vehicle that sees mixed or off-road use. Save the K&N, or even the OMNI foam for the street vehicles. Because if you have a turbocharger, the suction will pull the oil off the filter and onto the MAP wire in the throttle body, causing performance issues. In the end, Paper=best, Foam=next. A K&N, even with the pre-filter cover, is only marginal. Use just the gauze, and your asking for trouble in the long term. The 'Diesel Place' forum, did a exhaustive test and evaluation over 10 years ago. If you can locate it, it makes for a fascinating read. They tested in excess of 25-30 different brands, types, and were surprised themselves on the results documented thru a independent lab.

As you also stated, paper can be used/cleaned over and over. Andrew St. Pierre White , of 4x Overland did a piece on dust build-up in snorkeled trucks, as a everyday necessity to clean when in convoy, or heavy dust from wind etc. The amount knocked off each morning was sobering. He did a You-Tube article on it.

Maybe this is the article that scared me away from the reusable filters. I remember seeing a picture of a cylinder wall with superfine scratches.

 

[PNW EXPLR]

AC Delco

Check out this article I post every time someone asks.

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

Before spending your money on an aftermarket intake, let's debunk the misleading incomplete info about filtering and horsepower in the sales literature.

nicoclub.com

This is a great read! Absolutely amazing, the difference between the performance of an AC Delco paper filter vs a K&N. Guess I will be picking up a spare AC.
Thanks for this link. I love when I can see black and white data.

 

[Cort]

K&N makes an awesome product for specific applications however for most autos they are a bad choice. This is a great example of the power of marketing and greed over engineering facts and corporate morality. The auto industry is a dirty world when you pull the curtain back.

Thanks for posting that article.

 

[jimbofoxman]

Last truck I used a K&N but that was probably an early 2000's K&N. Hear lots of bad things about the K&N allowing too much in. So I've switched to only paper. Hear the Napa Gold Filters were pretty good......trying that one now.

 

[smritte]

The Article is very accurate when it comes to air flow and dirt collected. There are a few points that I believe should have been covered. One of them is history. K&N had a place in time where they actually made a difference. The K&N plant is not far from me and I have taken students there on tour's. I've met and questioned the engineers as well as seen the dyno sheets. Unfortunately their information is no longer accurate. I'll try to keep this short (yeah right).

For simplicity I'm just using simple numbers.

An engine is just an air pump. If you have a 6L motor it moves 6L of air (keeping simple here). No matter what you do, it is only capable of flowing this much. You cannot make it move more unless you make it bigger, make it spin faster or use forced induction.

Were just talking Stock

Old school engines up to the mid 90's were very restrictive when it came to intake, cam, exhaust. 6L motor intake will flow 5L new and clean, exhaust will flow 5.1L
The first thing we did on our vehicles was replace the intake and exhaust to let them breathe. Bam more efficiency= more power/mileage/better emissions.
Install K&N here
Now come's along emission and mileage standards as well as trying to wring as much power out of our outdated engine designs.
An example of this is GM and the Vortec Motors. They took a 1950's design and made it flow better. Yay more power, more efficiency.

What happened now was the 6L motor can actually flow 6L until the air cleaner got slightly dirty. Next Gen brought us better air box's on most (not Jeep) and now it will flow as much as 6.5L with a filter being replaced when it should.

The K&N data is from older more restricted vehicles and accurate for that generation.

I had mentioned above how jeep didn't improve their air box. I have not looked or done testing with the JK or the Cherokees so no opinion there. The TJ was the first vehicle I started experimenting with. The factory air box uses a small filter. When using the Delco filter it smothered it. My fix was replacing the air box with a modified mid 90's mustang box. Twice the surface area. My delco air cleaner did not effect it at all. My TJ was tested on the highway as well as dyno'ed at work.

Guess what did improve it some on the stock air box....Yep, K&N. Only slightly over the factory jeep filter and over 3k rpm but, there was an improvement. Too bad it let dirt in also.

As I said before, I kept this simple. I didn't use real math for RPM.

See..I did keep it under 3 pages.

 

[MazeVX]

Well ok, this got way deeper than I thought it would, but it's like always with a religious question like airfilters...
So I tell you what we did because we where curious...
Back than when I was into 1/4 mile racing we had a ongoing discussion so we talked a shop with a dyno into a experimental test, we brought the cars and filter stuff and he got the dyno.
We tested at least the stock and two different aftermarket filter solutions on 3 different vehicles.
1. Natural aspirated BMW 3L inline 6
2. VW turbo diesel
3. VW petrol turbo

The natural aspiring engine showed absolutely no effect, absolutely nothing besides the sound changed with the different filters.

The turbo diesel gained torque in midrange and power at the top end both somewhere around 5% with the least restrictive solution.

The petrol turbo did nearly the same as the diesel but stayed below 5% long term testing showed increased top speed but wasn't showing up on the dyno.

Long term testing with the turbo diesel showed less fuel consumption what makes sense given the improved midrange torque.

We did several tests with different vehicles over the time but the tendency stayed the same as mentioned above.

Turbo charged engines can gain power and torque and can get better fuel consumption.

Naturally aspiring engines never gained anything but noise.
That's what we learned. But that's not of scientific precision or so, just what we found out.

 

[MOAK]

Years ago I was a K&N fan.. I ran a street bug and a high performance euro sedan.. K&N are designed for race cars in clean environments. I use OEM paper filters. I’m gonna try an OEM washable filter next time ..

 

[smritte]

We tested at least the stock and two different aftermarket filter solutions on 3 different vehicles.
1. Natural aspirated BMW 3L inline 6
2. VW turbo diesel
3. VW petrol turbo

What's interesting is comparing manufacture claim's to real testing. Your results are right in line with reality. It's nice when a product actually makes a difference. Other times it makes no difference or you actually lose power.

 

[smritte]

Well ok, this got way deeper than I thought it would, but it's like always with a religious question like airfilters...

Heh, Yeah huh. This is what happens to me when I'm bored at work. I read forums.

 

[Desert Runner]

My old Chevy avalanche had one of those gauges from the factory. I totally forgot about them. Gunna order one from Amazon today. Thanks for the reminder.

Maybe this is the article that scared me away from the reusable filters. I remember seeing a picture of a cylinder wall with superfine scratches.

Just read the K&N test, supplied to us by TerryD. I believe the one I saw over a decade ago, had more brands/rebranded filters represented. Brands like :
STP
Walmart?
Fram
Napa
Napa Gold
Donaldson
Ford (Motorcraft)?
Purolator Gold?
Bosch
And some I can't recall now. It was extensive, more so than the K&N comparison listed above, but with similar results. I used a UNI for awhile on a 1985 straight 6, F-150 4x4. I had no dirt leakage, beyond how the air horn sat on the carburetor. Being a low horsepower engine, it didn't pull the air like a turbocharger would. So any dirt was more likely the filter housing, than the filter. On my ATV's, the Polaris carb model, I use with a K&N....WITH THE PRE-FILTER COVER, and have not seen an issue. The other is a UNI on a fuel injected Suzuki 700, which if your familiar, had a horrible OEM design prone to massive failure (leakage). That also has seen no issue with dirt getting in, but again these are not turbocharged, so the discussed issue with dirt leakage has been a none event.

 

[TerryD]

The Article is very accurate when it comes to air flow and dirt collected. There are a few points that I believe should have been covered. One of them is history. K&N had a place in time where they actually made a difference. The K&N plant is not far from me and I have taken students there on tour's. I've met and questioned the engineers as well as seen the dyno sheets. Unfortunately their information is no longer accurate. I'll try to keep this short (yeah right).

For simplicity I'm just using simple numbers.

An engine is just an air pump. If you have a 6L motor it moves 6L of air (keeping simple here). No matter what you do, it is only capable of flowing this much. You cannot make it move more unless you make it bigger, make it spin faster or use forced induction.

Were just talking Stock

Old school engines up to the mid 90's were very restrictive when it came to intake, cam, exhaust. 6L motor intake will flow 5L new and clean, exhaust will flow 5.1L
The first thing we did on our vehicles was replace the intake and exhaust to let them breathe. Bam more efficiency= more power/mileage/better emissions.
Install K&N here
Now come's along emission and mileage standards as well as trying to wring as much power out of our outdated engine designs.
An example of this is GM and the Vortec Motors. They took a 1950's design and made it flow better. Yay more power, more efficiency.

What happened now was the 6L motor can actually flow 6L until the air cleaner got slightly dirty. Next Gen brought us better air box's on most (not Jeep) and now it will flow as much as 6.5L with a filter being replaced when it should.

The K&N data is from older more restricted vehicles and accurate for that generation.

I had mentioned above how jeep didn't improve their air box. I have not looked or done testing with the JK or the Cherokees so no opinion there. The TJ was the first vehicle I started experimenting with. The factory air box uses a small filter. When using the Delco filter it smothered it. My fix was replacing the air box with a modified mid 90's mustang box. Twice the surface area. My delco air cleaner did not effect it at all. My TJ was tested on the highway as well as dyno'ed at work.

Guess what did improve it some on the stock air box....Yep, K&N. Only slightly over the factory jeep filter and over 3k rpm but, there was an improvement. Too bad it let dirt in also.

As I said before, I kept this simple. I didn't use real math for RPM.

See..I did keep it under 3 pages.

Well ok, this got way deeper than I thought it would, but it's like always with a religious question like airfilters...
So I tell you what we did because we where curious...
Back than when I was into 1/4 mile racing we had a ongoing discussion so we talked a shop with a dyno into a experimental test, we brought the cars and filter stuff and he got the dyno.
We tested at least the stock and two different aftermarket filter solutions on 3 different vehicles.
1. Natural aspirated BMW 3L inline 6
2. VW turbo diesel
3. VW petrol turbo

The natural aspiring engine showed absolutely no effect, absolutely nothing besides the sound changed with the different filters.

The turbo diesel gained torque in midrange and power at the top end both somewhere around 5% with the least restrictive solution.

The petrol turbo did nearly the same as the diesel but stayed below 5% long term testing showed increased top speed but wasn't showing up on the dyno.

Long term testing with the turbo diesel showed less fuel consumption what makes sense given the improved midrange torque.

We did several tests with different vehicles over the time but the tendency stayed the same as mentioned above.

Turbo charged engines can gain power and torque and can get better fuel consumption.

Naturally aspiring engines never gained anything but noise.
That's what we learned. But that's not of scientific precision or so, just what we found out.

Ok, now let's apply this info to everyday life. Performance air filters gains are up high in the RPM brand where you are moving enough air for the filter to become a restriction. We're not talking cruising along on the interstate st 2500RPM, we're talking top of 2nd gear, merging onto the intereste.

But we don't spend a lot of time at those engine speeds do we? It's an occasional thing. And I for one rarely see over 3k RPM when I'm off road.

With a fuel injected vehicle, it adjusts the AFR based on O2 sensor readings so if a filter flows 0.5% more air at 13% throttle, it'll richen up to deal with it, your engine will make slightly more power there, but your cruise control will tip the throttle plates closed a touch because now you're speeding up again.

I feel like cleaner air going into my engine is better than infinitesimal power gains full of dirt myself.