K&n air filter..... any good?

[holla]

Hi all, My GSA is due a service very soon and i was thinking if a k&n air filter would be a noticeable improvement over a standard one?

Has anyone fitted one and noticed any difference?

Thanks

 

[rce]

Modern air filters and air boxes don't restrict the engine like they used to in the past.

Personally I would go for the fine filtering of a standard filter, also will probably cost you less over the life time of the bike compared to K&N

 

[APE]

Been there - waste of money and a pain to service when a replacement paper filter would be a lot easier - avoid

 

[Wapping]

Hi all, My GSA is due a service very soon and i was thinking if a k&n air filter would be a noticeable improvement over a standard one?

Has anyone fitted one and noticed any difference?

Thanks

What do you find wrong with the standard one?

Nothing, much? Then keep it if it ain't broke.

 

[TeaPig]

Most damaging are fine dust particles, paper filters are v. good at removing this. Wheras...

 

[F104]

food for thought, would it be far better to go for a larger diameter air filter intake pipe? theoretical calculation on an easy rpm:
1200cc boxer at 6000rpm equals 600cc (4-cycle..) at 100 rotations per second = 60.000cm3/second air requirement
Intake diameter is about 4.5 cm = 15 cm2
60.000 / 15 = 4000 cm/sec = 40 mtr/sec = about 130 kph = about 80 mph.
So at 6000 rpm and less than 80mph, the engine can't get the air it needs freely. Ok throw in some volumetric efficiency but numbers should not be far off?

 

[Pukmeister]

I use a K&N on my current bike (and on the last one, both 1200's). They do need cleaning and lightly re-oiling between routine services but mine has pretty much broke even on price and I should be in the money with it now compared to the throw away stock items.

I ignore all the naysayers who read internet sites and then slag off K&N etc saying they pass dirt through etc etc, the inside of my bikes airbox has never been anything but spotless and my engine runs fine.

FWIW when I was a Marine Engineer we used to run Gas Turbines and large Diesels costing many millions with intake filtration near identical to K&N type filters in a salt-laden environment where the engines swallowed literally tons of air per hour. None of this machinery ever suffered from dirt ingestion either. Also, in the same environment a paper element would have become a soggy mess in days.

 

[Kremmen]

BMC filter for me, used them for years & never looked back.

 

[Steptoe]

I FWIW when I was a Marine Engineer we used to run Gas Turbines and large Diesels costing many millions with intake filtration near identical to K&N type filters in a salt-laden environment where the engines swallowed literally tons of air per hour. None of this machinery ever suffered from dirt ingestion either. Also, in the same environment a paper element would have become a soggy mess in days.

Perhaps there's not much dust in ocean/sea air

I see plenty in the airboxes of bikes with K&N's fitted.

 

[Rasher]

My own observations on smaller bikes were once you oiled them they were worse than stock.

personally rather change cheaper paper ones regularly, where I had my last bike setup (Hilltop Motorcycles) they advise on using stock filters and do not rate the likes of K&N as being any better.

Coming from someone who sells performance products and stuff I was surprised, certainly no hidden agenda.

He also tinkers with a lot of BMW's, but I was talking about my ZZR, got the impression he was talking generically though and was not impressed with "performance filters"

 

[grasmith0149]

I put one on my 04 GS on the recommendation of a BMW dealer. I think it gives a little bit more acceleration but lost a couple of mpg. It's always a trade off. As long as you service them as reccommended then you shouldn't have any problems.

 

[F104]

There's two ways to reduce the resistance across a filter element to be able to pass more air into he engine:
1) enlarge the filter size which is a bit difficult on the 1200GS
2) enlarge the holes in the filter material, eg more dirt into your engine.

I'l stick with the BMW filter, cheers

 

[TeaPig]

I ignore all the naysayers who read internet sites and then slag off K&N etc saying they pass dirt through etc etc, the inside of my bikes airbox has never been anything but spotless and my engine runs fine.
.

As one of the naysayers I'd like to point out that I speak from experience and not just regurgitation of web-site heresay. I used to run K&N's on a variety of bikes but in spite of properly maintaining them, in most cases they developed holes in the creases, sometimes upto a mm in diameter. Moreover the most damaging dust particles are too small to see and your engine will run 'fine' for many miles in spite of the wear that's taking place. Thereare many posts on this site covering the merits of K&N's which are also worth reading

 

[F104]

As one of the naysayers I'd like to point out that I speak from experience and not just regurgitation of web-site heresay. I used to run K&N's on a variety of bikes but in spite of properly maintaining them, in most cases they developed holes in the creases, sometimes upto a mm in diameter. Moreover the most damaging dust particles are too small to see and your engine will run 'fine' for many miles in spite of the wear that's taking place. Thereare many posts on this site covering the merits of K&N's which are also worth reading

To go on on this, the less filtration caused by different aftermarket filters will likely not cause issues in the the warranty period, but will result in a shorter engine life. As that will show up after the warranty period, great business to BMW and a good reason for them to remain silent on this issue

 

[GSband]

There's one solid question that remains : if K&N filters are better than OEM or paper filters, then why doesn't K&N provide testresults to that effect ? Wouldn't THAT be the way to gain millions of customers ? The only info one gets from K&N is sloganesk material. I found this hard to buy into.

So I went searching on the web - surely someone was as curious as I am, and (unlike me ) decided to test these things. So here it is : a very comprehensive testing of various filters, including K&N : http://forums.nicoclub.com/debunking-the-k-n-myth-why-oem-is-better-t180100.html

It's long, but it's an eye opener. Here's the gist of it :
K&N initially lets through more air than OEM; initially there may be a power increase.
K&N however clogs faster than OEM, diminishing air flow, and reducing power.
But, more importantly, from the beginning on K&N filters less particles (= lets through more dirt) than OEM.

In short, K&N may be very well suited for racing, where distances are relatively short, filters are exchanged or maintained before every race, and where engine life is not important.

On top of this, I had a talk with a representative of MAHLE (longstanding supplier of a.o. the paper filters of various BMW motorcycle types), at the Cologne Motorbike fair last weekend. I asked him what he thought of K&N filters. The responses were :
- that if K&N were a good deal (financially but more important : technically), BMW would use them
- K&N never substantiate their claims.

My R12GS is now close to 80000km, and I intend to keep it for a while. No way I'm using a filter that doesn't protect the inside of the engine. A filters' first job is to filter.

One remark, though : paper filters may collaps when wet. Oily filters may not collaps. But then I don't plan to drive my Beemer through deep water.

Cheers, GSband

 

[Rasher]

Excellent find

I just like to know stuff is new, even if a perfectly cleaned / oiled K&N was significantly better it would still rely on me cleaning and oiling it perfectly every time, much easier to just thrown in a new one.

As I have averaged a new bike every 3 years since passing my test I doubt I would have ever got a financial return from an aftermarket filter.

 

[GSband]

A better link to same test, easier to read, and with more data fields :
http://home.roadrunner.com/~jbplock/ISO5011/SPICER.htm
Cheers.