K&N Filter replacements - same problem as pod filters?

So I need a new air filter for my 1982 Maxim 400 XS400J, and I'm thinking of putting a K&N OE replacement filter into it. I have an online performance car part business and have a really good account for K&N products, so I can get it for quite cheap. But my question is, will I be running into the same problem as installing pod filters and having it go to lean? It will still be in the stock air box, but they do flow more.

Thanks for the suggestions folks

 

I doubt you'll have any problem.

The "Flow" is regulated by the size of the Airbox opening to atmosphere.

 

BLARG! and here all this time i thought the filter had some resistance to airflow

 

So will the K&N filter or any expenssive so called high performance filter inside the stock airbox improve performance over the stock filter? or does the stock airbox do too much of its own restricting to allow a high performance filter to show its real potential?
assuming everything is clean of course.

 

I put a K&N on my '82 XJ550 and I think it made some difference. It seems to help my motor when sustaining higher speeds and makes a slight difference in response to the throttle. The difference is almost nothing but it helps. It sure doesn't "Hurt" anything. You will be fine.

As a note...The filter I was replacing was an oil soaked piece of junk. That may be the only reason I noticed anything.

 

I would tend to lean toward the latter; the airbox is the primary restrictor.

The air filter itself would have to make some difference, you can't take it completely out for instance. But how much difference it makes between a clean stock filter and a K&N or UNI or something else in the stock airbox I really can't say.

I do know a CLOGGED filter makes a big difference. So does keeping a rolled up shop rag under your seat without realizing you're blocking the intake for the airbox (guess how I learned THAT.)

 

Another option that is cheaper and actually filters better than the K & N filter is to replace the paper on a stock filter with Uni foam. It's not hard to do with some patience. I removed all the paper from an old stock filter and measured a piece of Uni foam to fit the filter basket. Then I used GOOP to glue it in place.
Now all have to do is wash it, let it dry, and re-oil it. The Uni foam is more free flowing then the stock paper, but filters better than the K & N filter. Just another cheap mod that works.

 

Uni filters better than K&N ??
Who did that study ?? I'm just askin'

 

Just my .02, but after 'upgrading' to the K&N I switched back to a stock air filter. After cleaning and making a new inifoam gasket for the K&N, I didn't like the tiny gaps in the filter (when viewing thru the filter to a light, gaps looked larger 10 microns, whatever 10 micorns look like?). The new Emgo filter has no gaps, has a much larger surface area vs the K&N and was a decent price at $19. I'll keep the K&N as a back-up, but chances are I'll buy another Emgo in about 6 to 9 months.

 

Yes Unifoam is better than the K&N filter. Just look at them and you'll see the difference. The K&N you can see thru (big gaps = poor filtration) and the Unifoam traps more dirt particles as it's a finer weave in the foam.
I have a K&N filter (if anyone is looking for one) and they let too much dirt thru them. Infact, I had to wrap mine with filter paper from an old car filter to get it to filter properly, even when it was oiled. I don't trust them and won't use them in anything I own.
That's the reason I did the Unifoam mod to all my filters (cars. truck, lawn equipment, etc.) Sur e the K&N filters let more air thru them, and alot of other stuff too!

 

What does the word micron mean? The word micron is another term for micrometer (1 millionth of a meter).

A micrometer is a unit of linear measure in the metric system used to measure distance from one point to another. It is used like the inch, foot, centimeter and millimeter to measure length, width or diameter of objects.

Its scientific notation is µ. Some linear equivalents are 1 inch is 25,400 microns and 1 micron is .000039 inches.

Diameter of average human hair 70 microns
Lower limit of visibility (naked eye) 40 microns
White blood cells 25 microns
Talcum powder 10 microns
Red blood cells 8 microns
Bacteria 2 microns
Carbon black 0.6 microns
Tobacco smoke 0.5 microns

 

That's all fine and dandy when you talk about it in scientific terms as they advertise them, but when you can see thru the filters passages, those openings are the actual size of the dirt particles it is letting thru. Sorry, I'm not sold on the K&Ns technology, or lack of it. It's just mumbo jumbo to sell an over priced product.
Try putting a paper filter behind the K&N filter and see how much gets thru the K&N, then you'll see for yourself.

 

I'm not vouching for the effectiveness of K&N at dirt catching, I'm just answering the question posed by Silver Seca ("whatever 10 microns looks like?").

K&N filters will flow more air, and have about the same surface area as a stock filter, so of course they will have have bigger "passages" in some way.........otherwise, they won't flow more air! They (and UNI) try to compensate for the larger pore sizes with the oil technique, to try to capture some of the larger particles via turning the filter media into a type of "flypaper" via the oil (you can oil a paper filter, too, and decrease it's flow and increase it's capture ability, too!).

K&N's claim to fame is that their filters FLOWS MORE AIR while capturing particles down to a size than won't cause damage to an engine. Whether that's true or not I can't say, as I don't know who has done the studies that determine particle size vs. engine life considerations.....although I suppose OEM manufacturers, who have their warranty claims and reputation on the line, choose paper filters for a reason, and that reason may have to do with more than just an initial cost consideration.

People who knowingly desire more performance out of an engine---which generally requires more airflow-----are (supposedly) willing to trade longevity for performance. Think of a top-fuel motor.........lots of performance, but the engine lives for about 10 seconds. It's a sliding scale from that extreme to some other extreme, where the air filter has a choke hold on the air flow, and you get almost no engine performance at all, but that engine likely will last a long, long time (assuming it's not running lean, etc.).

If people are "deceived" into thinking that the K&N or other aftermarket filters do a better job of "filtering", then they may be reading something into the marketing hype that isn't really there. Note that on their own website, K&N goes to somewhat great lengths to talk about the benefits that their filters achieve (greater airflow and lower lifetime cost, due to the fact that they can be re-used rather than disposed), and very little useful information about filtration ability:

http://www.knfilters.com/filter_facts.htm

Some choice quotes:

"There are few areas more confusing than identifying dirt retention requirements when it comes to air filters. Most vehicle owner’s manuals remain silent on the point. In fact, few air filter manufacturers publish any information as to the filtration efficiency of their filters."

and then:

"We encourage customers to do their homework and be aware of the filtration capabilities of an air filter before they buy."


Well, how is a customer supposed to do this "homework" about filtration ability, when filter manufacturers don't provide such information? Even the ISO 5011 test that is mentioned is really a test of the flowrate of the filter and "dust saturation" points, rather than a "how clean is the air after it passes thru the filter?" type of test (generally speaking).


The reality is that for most users of air filters, who do not operate in very dusty environments (off-road, deserts areas, around rock quarries, etc.) are probably not going to see any decrease in engine life due to the lesser filtration abilities of an aftermarket K&N or UNI type filter (assuming they clean and lubricate them properly). However, users of such filters may see a decrease in engine life due to the lean conditions caused by the increased airflow that they provide, but that's a whole 'nother issue..........

 

What chacal said, plus this, with some polite disagreement:

http://en.wikipedia.org/wiki/Air_filter

The best filter, in terms of filtration, is an oil bath filter. You can see them on diesel trucks, at least some of them, and they are not for a motorcycle.

K&N is in the business of selling wet type air filters, and they make several claims, all of which are true but maybe not for the reasons we generally suspect.

Oiled medium filters (wet) are more efficient at catching particles. This means that in high dust or high priority applications, you can get a higher filtration for the same amount of airflow as a dry filter. The middle east is a (very) dusty place (if you haven't been there, you have no idea), and my ship's diesels use wet filters much like K&N (in fact they might even be K&N, they aren't just a performance filter company, that's just what you see because that is what the consumer buys) to filter out that dust. They also offer the added benefit of being reusable.

Now if a vehicle only requires x filtration, and you can get a more efficient filter, then you can choose to keep the same filtration for less pressure differential (flow) or keep the same pressure differential and choose better filtration. Whether effective or not, people buy K&N based on the true statement that you can get the same filtration while moving more air. I personally doubt it makes a sufficient difference for performance, but I do like the reuseability, and they do make OEM replacements that filter better with the same airflow (you can find them on K&N website, and are likely the ones dustinb was originally looking at).

So dry filters and wet filters are so completely different in function that they can't really be compared by look. If you are looking through the holes and thinking they won't catch dust, you are right, they are there to hold the oil, the oil catches the dust.

Dry, a filter meant to be wet would not work well at all! On the other hand, if you oiled a dry filter, I doubt you would get sufficient pressure on the discharge side of the filter. It would be like putting a shop rag over the intake vent.

Paper filters work just fine on a motorcycle or auto engine, and also simply require replacement rather than cleaning and re-oiling. That is why you don't see them replaced by manufacturers in favor of a more expensive, more work-requiring wet filter. You can get x filtration for y flow using either type of filter. There is nothing wrong with them. But a dry filter will have to be bigger than a wet filter for the same airflow. Don't mistake this for more airflow.

So wet filters do a better job of filtering OR allow more flow than dry filters, but not both at the same time.

For my engine, it's the same airflow, better filtration. It came with a oiled foam filter. But it also came without intake boots either! I added boots and oiled the filter.

One last thing, in case you caught this, Navy doesn't use oil bath filters due to the loose oil in them, it's a fire and environmental hazard. They don't use paper filters because of the cost increase and lack of self-reliance. Can't get a paper filter when you are in the middle of an ocean.

PainterD...i'm curious, how did you measure the amount of particles passing through the wet filter? EDIT: I see, I guess I missed it. I take it you have put a dry filter behind a wet one? I'm not saying that that PARTICULAR wet filter is more effective than that PARTICULAR dry filter, just that wet filters are more efficient, all other things being equal.

 

OK, I just put a piece of paper in the inlet to the carburators with the K&N filter installed. That way whatever got thru the K&N filter, ended up on the paper. It wasn't pretty.
So I did the same with the Unifoam filter I made and it worked better, less dirt on the paper, so I could see for myself. Unifoam filters better, thus letting less air thru than the K&N (more than likely)
So their claim is probably correct, but the filtration just isn't as good in my opinion. I wanted clean air and but not neccessarily more of it.

 

Unfortunately, as chacal says, there is no way to know if the K&N filtration is sufficient or not. And no way to measure the airflow without a lab!

It's certainly possible that "performance" filters increase airflow an extra bit by reducing filtration below stock.

Like I said, I wouldn't use a performance filter in my bike.