K & N air filter

[Kenny]

I have an 'as new' K & N air filter..but I'm a stickler for OE service parts so will be resorting to buying a standard air filter.

Anyone using a K & N and how do you rate it or even convince me to keep it !! I can see it going though !!

 

[Sean Kelly]

Hi Kenny

Interesting question....

Back when my 800 GS paralever was totally standard except for Keihin Y piece, I tried a K&N but sent it back 'cos it just wouldn't run. Astonishingly rough in fact and no idea why it was so bad.

After Andrew Sexton rebuilt my motor 1000cc, flowed, twin plug blah blah blah.... we used a K&N and the bike runs great.

Have you actually tried the filter on the bike?

Cheers

Sean

 

[Sylvester]

I have one on mine + a Y pipe and it runs great. Your next question will be "What jets am I running"? and I've got no idea. Runs great though honest! No flat stots and will pull right through the red line in top if I'd let it. I'm running a Seibenrock 1000cc conversion as well though.

 

[Sylvester]

I've got no flat SPOTs as well as flat stots sorry for the typo

 

[Steptoe]

Bin the K&N stick with the standard.

 

[Sylvester]

Bin the K&N stick with the standard.

Why? Have you heard any horror stories? And as the old saying goes "A K&N filter in the hand is better than the OE Filter in the catalogue".

 

[Rob Farmer]

Somewhere, stashed in the grubby corners of the Internet there's a report that was carried out by someone on K&N filters. They tested them against standard filters. The standard filters flowed just as much air and stopped smaler particles than the K&N...Damned if I can find it now though.....There we go http://duramax-diesel.com/spicer/index.htm

There is this article where the guys testing a K100 with various mods on the dyno http://ibmwr.org/ktech/dyno/intake2.html

His conclusion "We could not demonstrate to my satisfaction any performance improvements using the K&N filter that I feel would be statistically significant. Since the results of the stock filter vs. no filter indicate that the stock filter is not a restrictive element in the intake tract, it would be hard to believe any alternative filter could improve the output of the engine. Unless you consider the reusable aspect of the K&N filter as significant, I do not believe it is a worthwhile investment."

Interesting comment from the first test "compared to the ACDelco the K&N “plugged up” nearly 3 times faster, passed 18 times more dirt and captured 37% less dirt"

 

[lurcher]

Interesting comment from the first test "compared to the ACDelco the K&N “plugged up” nearly 3 times faster, passed 18 times more dirt and captured 37% less dirt"
Hi Rob interesting statistic how does that work?

 

[Rob Farmer]

I took that comment from the report. This is the full text :-

"In the chart above it’s important to note the different test durations for each filter. The AC Delco filter test ran for 60 minutes before exceeding the restriction limit while the AMSOIL and K&N tests each ran for 20 and 24 minutes respectively before reaching max restriction. In 60 minutes the AC Filter accumulated 574gms of dirt and passed only 0.4gms. After only 24 minutes the K&N had accumulated 221gms of dirt but passed 7.0gms. Compared to the AC, the K&N “plugged up” nearly 3 times faster, passed 18 times more dirt and captured 37% less dirt. See the data tables for a complete summary of these comparisons."

 

[Kenny]

Looks like my K & N is for sale then

 

[Redboots]

Compared to the AC, the K&N “plugged up” nearly 3 times faster, passed 18 times more dirt and captured 37% less dirt. See the data tables for a complete summary of these comparisons."

But in REAL LIFE, they seem to work AOK.
My bike that my mate rode to India, (the long way round), seems to have faired very well. Now running it with Keihan Y, needles dropped one and breather vented to atmosphere and it all seems very hunky-dory.

John

 

[mikyh]

My thoughts

Since I read what David Vizard wrote on A engines/Minis performance modifications, and building my own super Mini, I was hooked on K&N. Used it on all my vehicles since.
I was very surprised to read on the net the same study Rob's refering to.

Well, it made me wonder on the merrits of marketing...

One thing I remember, which might be in K&N's favour, is that as the dirt accumulates in the filter it actually filters better without loosing flow.
Who knows...

I'm going to buy a standard filter and try it on (now I've K&N). I'm in Germany next week.

 

[Rob Farmer]

I've got to say. I replaced a filter in my PD at the weekend. It was a Motobins replacement for the standard filter. Looked identical but had swelled up leaving only the bottom and top parts of the filter effectively working, when these got dirty there was enough reduction in performance for me to start looking for a cause. Fitting a new genuine filter made quite an improvement. If you're comparing the K&N to slightly used aftermarket filters then I guess it would be an improvement. The one I replaced had only been i for three thousand miles.

 

[Beemerboff]

I replaced the stock filter in my GS with a oiled foam Unifilter, which I made myself as Unifilter dont list one.

The air box seems just as clean with the stock paper filter, and I think the bike runs a little better too.

I have seen a few of these supposed tests on the K & N , and I am a bit suss too - none of them seem to replicate real world conditions and all are a bit light on how they oiled the K&N, etc etc.

There are a lot of people out there with a vested interest in putting you off buying a reusable air filter, so take these supposed tests with a pinch of salt.

 

[MattW]

One thing I remember, which might be in K&N's favour, is that as the dirt accumulates in the filter it actually filters better without loosing flow.
Who knows...

I can't understand how that would work mikyh?
As dirt accumulates in the filter it'll definitely filter better (to an extent, depending on the filter medium / design of the filter) but it will lose flow at the same time - it can't happen any other way.

In my previous life I used to design ventilation / filtration systems at the Sellafield nuclear reprocessing plant. The really 'dirty' bits of the facilities used to use HEPA filtration to trap airborne radioactive contaminants. When these filter were 'fresh' they barely met the minimum filtration requirements (didn't matter as two stage filtration was used) but as they 'loaded up' their filtration performance increased. At the same time the air flow reduced but this was compensated for by ramping up the extract fan speed. Of course you can't do this on a naturally aspirated bike so flow (and hence performance) decreases.

 

[mikyh]

Mattw

Please read this:
http://4by4connection.com/airfilters2.html

I wrote from memory, and I found some (claimed) stuff on the net to support it.
The claim was that as dust particles accumulate around the filter, they also absorb some of the filtering oil, and help and enhance the filtreation. It is supposed to work as the build-up of dust remains very airy and doesnt hurt the flow much.
I remember that Visard wrote that he saw offroad racing cars with a build-up of dust around their open K&N filters that made them look twice in size.

David Visard was a Mini guru back in the late 70's and 80's. Folowing his guidelines I had made a 1400cc A-engine making 110 hp at 7500rpm, out of a 1000c original, that had around 35hp at 4500rpm, in a good day. With a K&N filter, of cource
That car was pure fun...
Miky

 

[MattW]

Mattw

Please read this:
http://4by4connection.com/airfilters2.html

I wrote from memory, and I found some (claimed) stuff on the net to support it.
The claim was that as dust particles accumulate around the filter, they also absorb some of the filtering oil, and help and enhance the filtreation. It is supposed to work as the build-up of dust remains very airy and doesnt hurt the flow much.
I remember that Visard wrote that he saw offroad racing cars with a build-up of dust around their open K&N filters that made them look twice in size.

David Visard was a Mini guru back in the late 70's and 80's. Folowing his guidelines I had made a 1400cc A-engine making 110 hp at 7500rpm, out of a 1000c original, that had around 35hp at 4500rpm, in a good day. With a K&N filter, of cource
That car was pure fun...
Miky

I'll take your word for it Miky - no offence intended.

I had a copy of Visards book - it was my Mini bible . I built a couple of tuned Mini's but always had gearbox problems. I ended up with a straight cut Jack Knight dog box in the quickest one - worked but was horrifically loud (I had to wear earplugs driving down to see my girlfriend in Loughborough but still used to arrive with some sort of shell shock ) and the LSD was binary - tried to break your wrists round dry corners. I always fancied the kit that allowed you to mate the Ford 1600 x-flow to the mini box - even tougher on the gearbox though!
Happy days

 

[avrolancaster]

Stick with the OE filter.
I never found thet the K&N fitted very well either. I have often seen bikes that have clearly had the K&N fitted for some time and the filter is hanging and out of shape. Over hyped, over priced and over here springs to mind.

 

[Kenny]

Stick with the OE filter.
I never found thet the K&N fitted very well either. I have often seen bikes that have clearly had the K&N fitted for some time and the filter is hanging and out of shape. Over hyped, over priced and over here springs to mind.

Blimey Pete, first I'm selling it, then I'm not, then I am.......
but if you and St Eptoe say keep standard, then standard I'll go

Anyone want a K & N for the price of a standard one?

Thanks for all the input

 

[Steptoe]

I- none of them seem to replicate real world conditions .

What is this real world condition for air filters that you speak of ?.

It's a filter. It sits in a sealed housing and air passes through it.


What difference is test "air" as opposed to real "air" .

K&N are crap - you DO NOT get any HP gain. And they don't filter very well.

Forget the claims of working out cheaper over X amount of miles - You have to buy the filter, then the K&N cleaner and the K&N filter oil, and then feck about cleaning it and oiling it. Add that time up over the life of the filter.

If i service a bike fitted with a K&N filter it costs the owner more than it would just replacing a standard filter . It's a 30 second swop new for old with a standard filter. Job done, clean hands go for a ride.