Individual air filters

[Motogp]

Has anyone had any experience with removing the stock air box and running with individual air filters such as K&N? I would think this would improve the motors overall ability to get additional air into the FE and allow better performance and gas milage. If anyone has had experience with this setup, I would like to hear the pros and cons. I am considering the switch to my R1200S if there is enough benifit in doing so.:dunno

[mneblett]

Has anyone had any experience with removing the stock air box and running with individual air filters such as K&N? I would think this would improve the motors overall ability to get additional air into the FE and allow better performance and gas milage. If anyone has had experience with this setup, I would like to hear the pros and cons. I am considering the switch to my R1200S if there is enough benifit in doing so.:dunno
I have not done this, but I suspect you would not see significant gains on the top end (the stock air box isn't all that restrictive).

I further suspect that you will lose a considerable amount of lower rpm torque, the range where you spend 99.9% of your time. BMW does a pretty good job of tuning the intake lengths to maximize torque -- at lower rpm, longer intake runners make better use of the air flow pulses in the intake to help stuff as much air as possible into the combustion chamber before the intake valves close (the pressure pulses caused by sudden starting/stopping of air flow in the intake port as intake valves open and close can be used to effectively "draw in" more air if the positive pressure portion of the pressure wave in the intake tract is timed to arrive at the intake valve when the valve is open). You lose the long runner effects with filters clamped directly onto the throttle bodies.

As to the K&N idea, let's not open yet another K&N (aka "oil thread") thread. Suffice it to say they are crap -- 99.999% marketing hype, with lousy filtration. The OE BMW filters are simply not siginficant flow contraints (IIRC, several years ago, Don E. did dyno tests on a K-bike with the OE filter and a K&N, with no HP difference observed -- infact, there was no difference as compared to *no filter* at all, i.e., the OE filter flowed as well as no filter!)

Lastly, while you will have a fair amount of additional noise from the bike (the airbox also helps muffle the sound associated with the intake pressure pulses), don't be fooled into thinking that more noise=more power -- (insert your favorite snide HD comment here :thumb).

HTH,
Mark

[Polarbear]

UNI of Austrailia makes a fine filter I use in my GSA1200, but NO difference in gas or otherwise performance is seen with mine. The stock paper element is a pain to clean well, so I bought the 75$ UNI, which is foam and used for many many years. Cleanable:)...Much better for dirt riding, as I do. So far I've not had to clean it but once and it was still quite clean, with a lot of dirt riding:). Randy PS, I also did some quarter size holes in my airbox for the same reaons you speak, with NO change anywhere in the engine performance. I sealed them back to stock. :thumb:usa

[Motogp]

Thanks for the reply, I may go out and try to locate a couple filters that will attach to the throttle bodies just for kicks. If I can locate a manufacture that makes such a fit, I will let you know. I just may have to get in touch with N8 to see who he uses. I believe the individual filters is the setup on his race bikes.

[Polarbear]

So many sizes of these exist, I would think it easy to find these. You may even try a HD Dealer for some trick stuff they use, if looks are important. Otherwise, I've seen many foam types around dirt bike shops for the 650 class bikes, which are likely to be big enough for a twin Beemer. Randy:thumb

[deilenberger]

This was done by someone last year in the R1200R forum on r1150r.org - he claimed all sorts of wonderful things happened, and then he sold the bike. Never saw any proof of the wonderful things, so can't comment on how wonderful they were, or if they were the result of an optimistic butt-dyno. I did find it odd that right after he did this he sold the bike.

[cookie]

I'm a stock kind of guy. I would like to share my experience with free flowing intake systems. I am a GM for a Ford dealer, over 30 years exp. As you know with all these systems you need to thouroughly clean and DRY the filters before you re-oil and install. What I have found is without exception, if you examine the intake side of the ducting you can slide your finger and get a fine grit and you can visibly see a fine layer of dust. When compared to well maintained stock ducting there is not the same grit or dusting. Anytime you open up the micron filtering you are allowing abrasives into your combustion chamber and cylinder walls. I know many people love these products and I respect those opinions, I am just sharing my real life experience.
Jeff Anderson

[Polarbear]

Ford F350 and many before with K/N filters, equals NO dirt and/or dust of any kind in there. More work cleaning the filters, yes! But not buying new paper elements is a plus(maybe). Too many bikes to list with after market filters, that every case out perform the stock paper one for "extended use", except having to clean them:). UNI Foams seem to be perfect too on my new GSA1200, with no dirt issues of any kind, but you have to clean/oil them(75$). Paper elements are good indeed, but cleaning them out with air compressor is a fair solution a best and you have to buy another sooner or later(35$). The aftermarket ones are expensive, SO buying the original paper types have an arguement here! You'd can buy a couple+OEMs to equal the price of the others out there. In the life of your bike, you're likely to only buy a few air filters? Go figure:). :thumb

[cookie]

That's why i said you have to clean and dry and lubricate properly, if you are not anal about maintenance the factory filter is the way to go.