K&N results in ST1300

[sherob]

MDN actually did some dyno's with stock and k&N... the k&n did give performance gains... :eek: see link below.

www.motorcycledaily.com/21september04_kandnfilter.htm

[Dale_I]

The issue with K&N's that I have a problem with center around filtration efficiency. If a filter doesn't filter, why is it called a filter? If less restriction is what you would like, you can go without a filter. Better than that, furnish a ram air with a fresh air snorkel and increase the cylinder pressure a bit while you are at it.

Filters are a balance between filtration efficiency and the restriction that is caused as the filter does its job. The place to start when choosing a filter should always be defined as an efficiency level first, then a look at what choices there are once the minimum efficiency level is met. Not the other way around.

There are a lot of methods that can create hp and increase tq that are harmful to the engine.

[sherob]

So, what your saying is they don't filter? Why would MDN put somehing like a k&n in a bike if it wasn't going to do it's job? Do you offer some proof behind your accusation... a link perhaps stating what you posted?

I don't think MDN would post an article about a product they use in good faith that they know would damage your bike... :eek:

Just curious...

[Fireball18]

The difference between a stock Honda air filter and the K&N, is that the Honda element is a dry filtration element, and in order to do its job correctly, it has to be quite tight, while allowing adequate air through. The K&N is less dense, however the element is oiled, which helps trap junk as the air passes through the filter. I doubt that the K&N is less effecient than the Honda stock element.

[Dale_I]

<< So, what your saying is they don't filter? >>

Yes, in short, I do claim that the K&N filtration efficiency is not what a paper elements can provide. However, this is a somewhat complex topic that has no easy answer to provide an easily understood answer.

<< Why would MDN put somehing like a k&n in a bike if it wasn't going to do it's job? >>

That would be a question for MDN. However, I never claimed that MDN has any knowledge of how well the K&N filtration efficiency tests at or not. I tend to ask questions beyond the obvious and don't usually take the "company sales line" too seriously - with any company.

<< I don't think MDN would post an article about a product...they know would damage your bike. >>

True. So, the question is, "Do they know?"

<<The difference between a stock...filter and the K&N, is...the Honda element is a dry filtration element...to do its job correctly...has to be quite tight...The K&N is less dense...the element is oiled, which helps trap junk as the air passes through the filter. >>

Yes, a paper dry element will have a differently designed media, but oil does not help a less dense media trap dirt. Passage size and density allow particulate matter through, and if there is an oiled media there can be an accumulation or particulate matter at the surface. However, as restriction rises the oil and particulate matter will leach back into the system.

Here is where things get interesting. There are much more diverse differences than the method of filtration. Size plays a huge part in the equation. Since oiled stacked gauze is a thicker media, you will notice that there are fewer pleats than a standard paper media. This reduces the overall dimension of the filtration media area. As the media area gets smaller, to keep the same flow rate, the density has to become less and less. Even though the oild media may help temporarily trap some dirt, the lower media area will dictate a lower capacity for the smaller media area. Once restriction rises the lower density is quickly overcome and leaching begins.

If you get more porous, you lose filtration efficiency. The larger the holes are in the filter, the larger the contaminents are that can pass through them. This is why filters like the K&N and the AFE are not good at filtration. They are overly porous.

Think of it this way. If you have one 2" hose or two 1" hoses, which can you empty a pool quicker with? The one 2" hose. Because the one 2" hose has more area to flow. But, what if you have a 1.5" ball in the pool you want to keep in the pool. Will you keep the 1.5" ball in the pool using the 1" hoses, or a 2" hose? Only the 1" hoses will keep a 1.5" ball in the pool. Now, what if you have six 1" hoses to the one 2" hose and you don't want the ball out of the pool. Since you have increased the hose area over the area of the 2" hose by having six 1" hoses, and the six 1" hoses won't pass the ball, you would empty the pool faster and still keep the ball in the pool. This is like getting a much bigger media while keeping porisity small. More flow, more filtration.

<< Do you offer some proof behind your accusation...>>

Sure, but this will be a little long - so grab a cup-o-joe and here we go:

The very easy way to tell which filter is best is by looking at filtration efficiency results, then comparing which one has the least restriction in the application you are using. That way you can have a minimum acceptable standard for filtration, and the least affected by the flow volume you need.

I own a diesel performance company that does research and developement on performance engines in the light duty market. Although our specific testing deals with these applications, most of our testing applies to most engines in general. I will try to mention when this is not the case as I go on.

The one thing that needs to be mentioned is that standardized testing is usually not done at the levels of intake volume you see in a modified truck. For instance, the SAE J726 filtration efficiency test is done with a 240 cfm flow amount. Where that is horribly inefficient in performance diesel engines that consume in excess of 950 cfm fairly easily, in a 1100cc motorcycle engine that flow rate would be a bit high. Although they are not application specific, they are beneficial when comparing filters against each other because the tests are standardized and take the ability to skew the results in anyone's favor. However, I am a big advocate of in application testing once minimum standards are met during initial comparison.

When speaking of max flow rates, there is usually a flow rate given for a certain measure of restriction. Restriction amounts reflect how much vacuum exists between the filter and the engine. Where vacuum is usually measured in inches of water column, it will use mercury (Hg) and restriction will use water (H2O). There are 17"H2O for every 1"Hg, so restriction is simply a finer measure of vacuum.

The max flow rate at 8" of restriction will be different than the max flow rate at 10" of restriction. The more restriction measured, the more cfm will generally flow through the filter since the vacuum will be pulling more air through it. You will actually want the highest effective flow rate to be substantially above the engines ability, so you can run the engine with the lowest restriction possible.

But, and this is where it gets tricky, these are not linear relationships. A certain filter may perform well under a certain restriction, but when that restriction in increased, it may be out of range for its ability. So, to effectively rate a filter for a specific application, it would probably be advantageous to run restriction tests at the highest level of cfm consumption for that engine. Using restriction as a indicator for the ability of cfm flow, you might be able to tell which filter has the higher true maximum flow rate by which filter needs less restriction to supply the engine with its max cfm requirement. And, as long as the filtration efficiency is not compromised, you will have the best filter.

But, you start with the best filtration efficiency first, and then use that media to get sized to your max cfm rate. Then the filter is filtering and you can gain performance without sacrificing longevity.

So, we took filters and submitted them to an independant lab for testing. The standardized test method SAE J726 and is the industry standard for rating filtration efficiency. The results are all related to this same standardized test. The same particle size is used and regulated by the test standards, although air filters are not rated by the particle size like liquid (oil, fuel, etc) filters are. Air filters are rated by the percentage of particles that are accumulated during the test in grams and is compared with the weight of the initial dust introduced. Specific to the test referenced, flowing 240 cfm until 10" H2O of restriction was reached. These amounts and sizes of particulates are administered with initial and cumulative results given:

A4 course dust @ 0.028 g/ft^3 air.
During initial efficiency 0.004 g/ft^3 air for 30 minutes.
Initial efficiency= 1 - wt. gain of absolute/wt. of dust fed x 100
Cumulative = wt. gain of element/(wt gain of element + wt. gain of absolute) x 100

The findings?
K&N produced 97.1% efficiency at initial level (clean filter) and 99.2% at cumulative (when the filter is more packed)
The paper element we used was a Donaldson which provided 99.8% initial and 99.9% cumulative.
Stock Motorcraft paper element was 98.7% initial and 99.9% cumulative.

The interesting part was that the paper elements outflowed the K&N in all cases except initial restriction, when the K&N was allowing 3% of the dirt that hit it through the filter.

The next observation was that because of its smaller media area, K&N's capacity was less than half the Motorcraft filter and about 1/4 of the Donaldsons capacity. Which means that it would clog up faster, become restrictive quicker, and need cleaned more often.

You also need to be careful when reading manufacturers claims. K&N uses an initial flow for its cfm rating and a cumulative filtration efficiency for its filtering abilty claims. It's initial filtering ability is below standard but allows great flow. Once the filtration is up, the flow has been compromised. So, basically, you get good flow and poor filtration, or good filtration and poor flow.

Again, it should be mentioned that the ST1100 is not a turbo charged engine and its ability to ingest dirt particulate will be better than the engines we deal with. A compressor wheel on a turbo is turning in excess of 140,000 rpms and is made of light metal. However, if filtration efficiency needs to be exceptional for the large turbo engines and the paper elements ability to flow large mass volume is not decreased as much as the K&N, I can only assume the same truth for a much smaller non-turbo charged engine.

Sorry for the length, but I did hold back and can supply more technical information if necessary.

[sherob]

I thank you for your answer... and considerable knowledge as well. I have never used them on my bikes, but have on my trucks and have been happy with them. The fact that even Honda dealers put them in their bikes when doing pipe and rejetting for performance reasons on Vtwins would be a concern then... forgive the rambling... :coffee1:

I guess this will fall along with the "fastest color" debate... :D

[Dale_I]

sherob -- I'm not sure that when Honda installs them on V-Twins for performance reasons it would be a concern. Racing is racing and what a racer will do to get hp is a far cry from what a tourer will do and expect the engine to last 100K miles+. Go to a tractor pull and you will see trucks with no air filters on them at all. I tell customers all the time, I don't build a quarter mile truck the same way I build a truck pulling a 36ft fifth wheel.

I guess my point is that all the information in the world will not make much difference if the right question isn't asked. In this case, I would ask what the minimal acceptable filtration efficiency Honda requires for their motorcycles? I really don't know.

I've already admitted that a gasser engine will be able to ingest more dirt particulate than a turbo diesel. Heck, for the same rpm a turbo diesel will mandate twice the intake cfm flow and produce almost three to four times the exhaust volume of a similar cubic inch gasser. They are just apples to oranges.

What I am getting at is that it doesn't surprise me that a clean K&N will allow tuning that may increase hp slightly. However, testing results in knowing that the hp created will not last very long before you will see a return, and in some cases decrease, in performance when the filter is packed. And, while that additional flow is available you are passing more contaminents.

I think it comes down to a personal decision, if the 4 to 8 hp increase is worth it to you. For me? I'll take good filtration any day. But then, I run synthetics and change my oil too often as well. I just want to keep the bike rolling as long as she can - trouble free. If I needed 6 or 7 more hp I could find it - but it really isn't critical to me.
:sbs1:

[Carl_T]

Dale, my bike and I thank you for the info. and the time it took to type it :)

[sherob]

I was never considering it for my ST... was for my cruiser :D ~60hp on a good day... WOW! I posted for those that use them and swear that they give them a boost... thought I would share proof.

Thanks for you enlightenment and wealth of info... as always, this place comes thru :)... back to work... :bow1:

I owe, I owe, it's of to work I go...

[lionroyboy]

If it means anything, I put the K&N air filter on my bike without realizing there could be any negative consequences. But, I can't feel any increase in power, so, when my next scheduled air filter change comes up, I'm replacing the K&N with a Honda air filter, rather than re-oiling the K&N. I think I read the same information about HP increases from the K&N, which is why I purchased it in the first place! I used the reusability factor as an excuse to pay more for the K&N. However, the real reason why I wanted it was for more power! The article I read convinced me that I would notice a significant difference in power and acceleration, but I just didn't feel a change. I'm glad that there are people on this site who know more about bikes than I do, so that I'm less likely to do something I'll regret later!

[sherob]

I always chalk those up to lived and learned... done it many times with other things. Sometimes you get what you pay for, sometimes not. With my ST I'm really not interested in performance gains since it has a rediculous amount of Hp and Tq I'll never use :D My Vtwin on the other hand was another story... :eek: I plan on keeping this ride for a LONG LONG time... not damaging it internally is essential for that plan. I'll pay extra for the Honda air and oil filters. :rolleyes:

[hippo888]

Instead of well-worded technical expertise, I use a simpler method of gauging how well K&N's filter.

Look at any intake tract downstream of a K&N filter. If that filter has been used for a significant time period, say, 10,000 miles, then the intake tracts will be BLACK and oily with dirt that has passed by the K&N filter.

Just my experience.

[sherob]

Instead of well-worded technical expertise, I use a simpler method of gauging how well K&N's filter.

Look at any intake tract downstream of a K&N filter. If that filter has been used for a significant time period, say, 10,000 miles, then the intake tracts will be BLACK and oily with dirt that has passed by the K&N filter.

Just my experience.

This is absolutely correct... I had mentioned this before when talking about k&n on this forum... I clean my intake and throttle bodies on my Dodge QC every 6 months or so... the do get a bit dirty and grimy... but we are talking a V8 compared to a percision V4. I had a AirRaid intake on an Expedition w/k&n... it made HUGE difference in performance... again... V8, not V4. Still had to clean intake and throttle bodies. This is why it won't go on my ST. :)

[tdeboeser]

I used a K&N with my old VTR (Superhawk), while I never did any real investigation on how well it filtered, tho I used it without hasitation. Many VTR owners never had issues.
I didn't notice any power gains, but I wasn't always WFO - which is where a filter like this will pay off. But I did notice the sweet intake sound, better than the exaust sound.
In my area there is not alot of sand/dust, which from some sources I've read will defeat a K&N filter quickly.

My $0.02,

Tom de '03
VA

[beastie]

Now THIS is why I love this forum :D WOW! what a wealth of information. And I thought Carl and I were verbose. But Dale may have set a new record ;)

[miller205]

I think Paul has an interesting point. I agree the K&N does not capture the same level of particulate as many paper filters, but the question is, so what? If Paul can get 165K miles on his bike with one (and there are many others using K&Ns doing the same thing), just how much damage is that extra 3% doing? Is it the difference between rebuilding the top end of your engine at 200K miles vs 250K miles? If so, how many of us would be effected by that? Anybody you ever heard of needing to rebuild because of excessive (non-lubricted) wear on vavles or pistons?

Intriguing discussion, but more than a lil esoteric. Unless you continually ride in the dirt/dust, or you're planning to set a max mileage record, I don't think you'll ever see a noticable difference. Just my $.02 worth.....

[sherob]

Well, living in El Paso he would have the dirt/dust environment for sure :bow1: As the old saying goes... whatever floats your boat. If it makes you happy, you like the results... do it :D Since I have the drive forever warranty... I don't want a PO'ed Mother Honda :D

[Dale_I]

Mike - Exactly what I was getting at when I said, "...what the minimal acceptable filtration efficiency Honda requires for their motorcycles?"

In the applications I deal with, I can honestly say that the re-usable filters cause measurable damage to an expensive component (the turbo) and cause low cylinder pressures due to valve deterioration. But moving 950+ cfm through a turbo putting out 30+ psi into a 444 ci engine a little different than this application.

Again, just a personal decision. But, I thought I would offer a little more than an opinion or case study, which is where the "K&N vrs Paper" debates generally degrade to.

For me? I choose to ride... :biker:

[NormanPCN]

Instead of well-worded technical expertise, I use a simpler method of gauging how well K&N's filter.

Look at any intake tract downstream of a K&N filter. If that filter has been used for a significant time period, say, 10,000 miles, then the intake tracts will be BLACK and oily with dirt that has passed by the K&N filter.

Just my experience.

Ditto. Personal experience in my 4x4 4Runner, very dusty conditions!, showed junk getting by the K&N filter. After a trip to Moab, I noticed the trademark red dirt behind the filter. Red shows up very well against the black plastic of the filter box.

[NCSam]

Dale I ......... Very interesting and thanks for your efforts. Couple of questions before I cancel my order for a K&N air filter;

* Have you checked out K&N's web site thoroughly to verify for example, their "independent" tests? Their testing procedures? ... Did you look at the section entitled "facts" (Paper vs K&N), etc., etc. What say ye?

* Would you mind if I cut-and-pasted your remarks/findings to K&N to see what their response would be and post the results on this thread? ... assuming they do respond!

At this point I am reconsidering my decision to put a K&N filter on the bike. I've run K&N's on every bike I've owned in the last twelve years; '93 ST1100, '97 Valkyrie, '01 Goldwing, '02 1800 VTX, and have not experienced any problems. However, as you will note - I haven't put a lot of miles on any of the bikes. Totaled the ST in '96 and it took me until last Spring to come back to my real love; Sport Touring / ST !!! I do intend however, on sticking with the '04 ST1300 for quite some time.

Perhaps you are wondering why I'm still wanting the K&N? Because, ... I just do! :) ... I also like the "sound" and the "perceived" :? hp increase - not to mention the economics. It would be interesting to see if I could get a "real" (not canned sales pitch) response from them.

Sam

[jackpine savage]

Hevnbound, I too would be interested in K&Ns response. My BIL who always runs K&N keeps asking me when I'm going to order one. He of course swears by them.
David

[Dale_I]

Sam -- Feel free to copy and paste whatever you would like. In fact, I have the internal K&N test results from their published tests in my file, along with AFE's. If you would, link me to the document you would like me to comment on and I will do my best to give you an honest opinion of what they state.