Air Filters

[coaz4x4]

Ok... I'm willing to be redirected to other threads about air filtration, but couldn't find any in search, so please post up a link and I'll do some reading.

2002 CB900f

I need a new air filter. As far as I see it my options are K&N vs 'stock replacement' (Honda Brand paper).

Obviously the issue is:
filtration: more is better, but you don't want to restrict air flow more than is 'necessary' (wherever that imaginary line is)

K&N =+/-$50
Honda =+/-35

Conclusion #1 - a K&N will only take 2ish years to pay for itself (assuming yearly replacement) then it's gravy as long as it's maintained properly (fold maintainece kit in to 'other' costs of owning the bike)

I did a lot of research on my Jeep before going with an AEM Dryflow, the consensus for me on that was a) I have to clean the thing so damn often that it paid for itself a lot faster, and the dryflow just needs some simple green and water, so it's simpler.

The consensus on the 4x4 forums was that paper was better overall... the main argument over the K&N is that as you allow more air flow, more crap is going to get through. There was also the 'attitude' that they needed to be a tad bit dirty to work properly, and since no one is really capable of doing the cleaning/oiling right, and consistently, filtration will suffer. Especially with the way the CB900f filters through the inside - out, I could see the oiling as being a bit of a chore.

I also have a WRX, and in researching mods, came across these:
http://web.archive.org/web/20050330043143/http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm
http://www.bobistheoilguy.com/airfilter/airtest1.htm

As with some studies that I read on motor oil being tested in NYC taxis (changed my opinion of the stuff for good), I was surprised to find that these more 'OEM' parts protected your engine better.

Conclusion #2 (this one is up for debate): paper air filters will cost more over time, but along with other regular maintainence to the motorcycle will extend the service life of the motor.

Insert your $0.02 below. Thanks!
-Peter

[Bueller]

OEM
Some of the "performance" filters produce less HP

[rybo]

OEM
Some of the "performance" filters produce less HP

This was my experience for sure.

Subject bike was an FZR 400. It made considerably better power with the stock airbox and filter installed than it did with either the K&N in the stock airbox or with the airbox removed and pod filters installed.

[coaz4x4]

I was surprised to find on the WRX how so many of the stand alone mods like an intake, cat-back exhaust or BOV actually reduced HP without a proper set of complimentary mods and a tune...

I've always used stock replacement/Honda brand/Honda dealer recommended parts for everything else, since I also figure the engineers at Honda knew a thing or 2 about the overall design/mgmt of the motor.

[TransNone13]

I've always been pleased with BMC. I definitely did not notice a decline in power in either of the bikes I've used them in.

[Bueller]

You won't feel anything. Any gain or decline will be so minimal you would never notice it. But put it on a dyno and it can be measured. If it is going the wrong way you would be spending $ to make your bike slower. Just like running premium in a motor that only needs regular, you pay extra to reduce performance, but it makes the person "feel" like they are making an improvement.

[TransNone13]

I mean I doubt you'll notice it with everything else unchanged, but with a full exhaust and custom fuel mapping I'm sure it helps.

[Sarge]

I put the slip ons on my bike, then 2-3 days later put the K&N filter in. It didn't feel much different, but it definitely sounded better and the increased airflow is obvious. I also changed the mapping at the same time. With the filter, slip ons and map change together though, it definitely made a HUGE difference. But, like others have said, I did it as one part of a comPlementary set of mods.

[TC626]

I have run K&N's in every vehicle i have owned, and have always seen inproved gas mileage to some degree. i suggust googleing th K&N part number, since the bike sites seem to run high on the pricing.

[Sarge]

+1

I got mine on Amazon for much cheaper than I could find anywhere else.

[coaz4x4]

I'm not looking for a HP/MPG gain over stock as a benefit of the filter install, nor do I plan on a exhaust or map.

Cost and engine longevity are my 2 factors, and the latter is a cost factor, just with a different label.

Let's be honest anyways, who saved enough on air filters over time with a K&N or anything else for that matter to pay for their next vehicle or vacation?!

[Vellos]

If you don't ride the bike your engine longevity will go way up and the cost to maintain an unridden bike will go way down.

[coaz4x4]

Point taken. To try and state it more clearly, the increased cost over time of paper filters could cost less in engine maintainence if less particulate gets thru, as compared to the shorter term savings on air filters.

[brennahm]

You're splitting hairs. Go ride!

[Ezzzzy1]

You're splitting hairs. Go ride!

Agreed!

However anyone that says you wont notice a difference with ANY filter that allows the bike to suck MORE air, LESS restricted is on crack. Thats how motors work, someones opinion can not change that. Its a fact.

You can see it on the dyno and you can feel it in the throttle response. Not sure that its all that necessary on a stock bike (definitely a good start) but when you start to get into other modifications its vary important... You wouldnt want any motor exhaling faster than it could breath in, its that simple.

I use K&N. There are several non-resolving conversations around the net about what one is better.

[coaz4x4]

If you don't ride the bike your engine longevity will go way up and the cost to maintain an unridden bike will go way down.

You have also gotta use miles instead of years as the scale for longevity.

[coaz4x4]

Agreed!

However anyone that says you wont notice a difference with ANY filter that allows the bike to suck MORE air, LESS restricted is on crack. Thats how motors work, someones opinion can not change that. Its a fact.

You can see it on the dyno and you can feel it in the throttle response. Not sure that its all that necessary on a stock bike (definitely a good start) but when you start to get into other modifications its vary important... You wouldnt want any motor exhaling faster than it could breath in, its that simple.

I use K&N. There are several non-resolving conversations around the net about what one is better.

Yes, it is hair splitting, but isn't that every other thread on most forums? Tires, batteries, helmets, etc. An I bet both of you split plenty of hairs when it comes to your ride.

That being said, you've chosen K&N for performance, not for filtration, as far as I'm reading it. I'm basing my decision on the opposite. My bike has plenty of power for me, and to sacrifice .25HP for the sound/feel one filter can provide me over the other is not a consideration for me. If you feel that's a worthwhile balance, I respect that.

Brennham - what do u use?

[brennahm]

However anyone that says you wont notice a difference with ANY filter that allows the bike to suck MORE air, LESS restricted is on crack.

It's not that ezzy man. Every asshole who puts an exhaust on his bike thinks it helps power but in a scary large number of instances...they've done the opposite.

Air filters are the same thing, and dyno's have proven over and over that the "butt dyno" is not an effective measurement device. People spend money on something, they're bound to think it helps. So yeah, you'll usually "notice a difference", but that doesn't always mean there is one or that it's a positive one.

[UglyDogRacing]

brennham is right. anyone who thinks replacing an oem air filter with aftermarket will notice a difference is on crack. we've done dyno comparisons on a few of my bikes over the years and there is no noticable difference. i do use a BMC in my race bike only because I can clean it after every race weekend.

don't run a K&N on a diesel. they let too much through. i ran one on my Dodge and it dusted the turbo so bad I had to replace it last year.

[brennahm]

FWIW, they're also finding the K&N's are really messing with late model cars' MAF sensors (or something similar). Hence the new dry filters. It'll only be a matter of time before our bikes are equipped with sensors that don't like K&N's.

And finally, it's pretty well known in the DR-Z community that you don't run a K&N unless you don't ride dirt...they just don't perform in dusty conditions and you lose your valves.

[Ezzzzy1]

Yes, it is hair splitting, but isn't that every other thread on most forums? Tires, batteries, helmets, etc. An I bet both of you split plenty of hairs when it comes to your ride.

That being said, you've chosen K&N for performance, not for filtration, as far as I'm reading it. I'm basing my decision on the opposite. My bike has plenty of power for me, and to sacrifice .25HP for the sound/feel one filter can provide me over the other is not a consideration for me. If you feel that's a worthwhile balance, I respect that.

Brennham - what do u use?

So you are saying that K&N doesnt filter air, or that I dont care how well the air is being filtered? Either way, I chose it because I have used several others and prefer it... I did get gains from it like I have from every mod I have done. The manufactures of these bikes set their tolerances really low - Meaning the factory specs are waaaay under rated. There is a difference between a good aftermarket product/company and a bad one. The good ones are only improving and maximizing products based on the low factory tolerances. A good aftermarket filter will not hurt your bike in the least. It looks like you are assuming that it is a less clean alternative? I would love to see what you are talking about and where that information came from...

It's not that ezzy man. Every asshole who puts an exhaust on his bike thinks it helps power but in a scary large number of instances...they've done the opposite.

Air filters are the same thing, and dyno's have proven over and over that the "butt dyno" is not an effective measurement device. People spend money on something, they're bound to think it helps. So yeah, you'll usually "notice a difference", but that doesn't always mean there is one or that it's a positive one.

It is that ezzy brenn... More air = More power.

I understand your philosophy and know that is how some people are but that is not how it always is. Good aftermarket filters allow for more potiental power out of the same motor.

[Ezzzzy1]

brennham is right. anyone who thinks replacing an oem air filter with aftermarket will notice a difference is on crack. we've done dyno comparisons on a few of my bikes over the years and there is no noticable difference. i do use a BMC in my race bike only because I can clean it after every race weekend.

don't run a K&N on a diesel. they let too much through. i ran one on my Dodge and it dusted the turbo so bad I had to replace it last year.

I got your crack! lol. Just because air filters dont always translate into gains on the Dyno doesnt mean they are worthless. An engine SUCKS air, the easier it is to do that the less it has to work all around. Anyone will tell you that = power. Opening the front door wider allows for easier passage all the way through, thats why people do it. Freeier flowing system?? I didnt just invent that word today, did I?

Whatever... This is going to turn into a circle jerk. Enjoy running your stock filters that bottle up your motor.

[UglyDogRacing]

whatever you say Ezzy

[Bueller]

And the stickers are not to be underestimated either, huge gains to be had there (depending on placement of course).