Air Filters: Do They Really Make A Difference?

[Guest klinquist]

Common sense tells us that more air flow = more power... but do a K&N or BMC filter really make any difference on the VFR (specifically 6th gen)?

I'm also a BMW (car) enthusiast and cold air intakes tend to give you almost no horsepower, even when paired with other mods. Of course, I know there are other cars out there that do get power.

The stock air filter looks pretty good. The K&N seems to have a smaller area. The BMC looks to be about OEM-sized. I don't like cleaning and re-oiling filters - I'd rather spend $25-30 on an OEM filter and replace it every 15k miles than re-oil a $75 filter assuming similar performance.

I just installed a PC3+coyze and have gutted cans on their way to me - just wondering if an air filter will 'complete the system' or if it's 'not really necessary'.

Thanks!

[Guest]

I have a Pipercross one from the last two weeks... and I'm very happy of it, especially for accelaration :happy:

actually I'm waiting the biannual revision (dunno in USA, in UK it's the MOT), when passed, I'll try experiments with supplemantary resistor on the IAT (maybe about 1 kohm would do the job) to enrich a little

theoretically, it would increase the overall fuel curve... when I'll do the mod, I'll share impressions

I don't feel necessity for a PWC, 'cause my exhaust it's perfectly tuned for my bike (curiously it is for a Cbr 600 :blink: )... no annoying 4/5000 rpm's hole

perhaps I'll want the PWC when I'll do the Big Bore :laugh:

Snap! I`ve got the pipercross filter and works great, the filter goes right to the edges. Bit faster on the pick up too! I`ve opened up the top airbox cover which makes a much bigger difference and induction sounds awesome. Started off with with flapper and snorkel mod, and just had to take it further! Recommended!

[Guest]

Common sense tells us that more air flow = more power... but do a K&N or BMC filter really make any difference on the VFR (specifically 6th gen)?

I'm also a BMW (car) enthusiast and cold air intakes tend to give you almost no horsepower, even when paired with other mods. Of course, I know there are other cars out there that do get power.

The stock air filter looks pretty good. The K&N seems to have a smaller area. The BMC looks to be about OEM-sized. I don't like cleaning and re-oiling filters - I'd rather spend $25-30 on an OEM filter and replace it every 15k miles than re-oil a $75 filter assuming similar performance.

I just installed a PC3+coyze and have gutted cans on their way to me - just wondering if an air filter will 'complete the system' or if it's 'not really necessary'.

Thanks!

well not sure about then beam but an ls1 or so on intake and exhuast adds 30-40 rwhp...you gotta first have power to make more.. but the k@n are great filters so is the bmc, not sure the "gutted" cans work or and aftermarket would sell them..

[Ryanme17]

well not sure about then beam but an ls1 or so on intake and exhuast adds 30-40 rwhp...you gotta first have power to make more.. but the k@n are great filters so is the bmc, not sure the "gutted" cans work or and aftermarket would sell them..

Yes, but the stock intake and exhaust on the LS1's are the restrictive part of the system, sometimes a redesigned air box can make a huge difference if the stock one is poor (I got an additional 2 mpg on my Civic with an air intake). Just not sure if that is the case here.

[maddog]

I have my doubts whether an air filter will make any real difference on the VFR. Maybe with exhaust and mapping, but I'm not into all that. Stock Honda filter for me. Did have a K&N on my old '96 VFR, and didn't notice any real benefits. I also thought it was a pita to remove, clean, dry, oil and replace a K&N, as opposed to just swapping out with stock.

[Guest]

I have my doubts whether an air filter will make any real difference on the VFR. Maybe with exhaust and mapping, but I'm not into all that. Stock Honda filter for me. Did have a K&N on my old '96 VFR, and didn't notice any real benefits. I also thought it was a pita to remove, clean, dry, oil and replace a K&N, as opposed to just swapping out with stock.

The performance difference is prolly next to negligible. However it does keep you from forking over cash to the stealership every time a filter change is due. Once you've propped up the tank and removed the airbox lid it's only a 10 minute job to clean and re-oil the aftermarket filter whether it's a K&N or a BMC, or anything else. Personally, If I can keep a proven permanent filter in place as opposed to replacing periodically with the OEM for $$ every time, I'll take the aftermarket solution. Just a difference of opinion.

[Ryanme17]

I have my doubts whether an air filter will make any real difference on I also thought it was a pita to remove, clean, dry, oil and replace a K&N, as opposed to just swapping out with stock.

The performance difference is prolly next to negligible. However it does keep you from forking over cash to the stealership every time a filter change is due. Once you've propped up the tank and removed the airbox lid it's only a 10 minute job to clean and re-oil the aftermarket filter whether it's a K&N or a BMC, or anything else. Personally, If I can keep a proven permanent filter in place as opposed to replacing periodically with the OEM for $ every time, I'll take the aftermarket solution. Just a difference of opinion.

I have to agree. If you've taken the time to lift the tank and unscrew the top of the airbox, it's hardly any more work to clean and re-oil the filter. I guess if you're impatient than waiting for it to dry is no fun.

[coderighter]

This is a interesting read.

http://www.rc51.org/airfilt.htm

I believe that because bikes don't have an airflow meter like cars do, they have no way of compensating for changes in incoming air as it corresponds to throttle position. This would also include altering the airbox. This is where a PCV with Autotune shines.

[Guest]

Snap! I`ve got the pipercross filter and works great, the filter goes right to the edges. Bit faster on the pick up too! I`ve opened up the top airbox cover which makes a much bigger difference and induction sounds awesome. Started off with with flapper and snorkel mod, and just had to take it further! Recommended!

Danny:

Got any pics of your airbox mod? I've heard a lot of good stuff about Pipercross filters.

BTW all, BMC actually makes two filters for the VFR. A standard street filter and a racing filter. I have to assume the racing filter has a larger flow area.

Pete

[enzed_viffer]

This is a interesting read.

http://www.rc51.org/airfilt.htm

It is indeed, especially the bit about "in normal street riding, you rarely use more than 10% throttle". I'd already found that out, as I *did* have my throttle marked to aid setting up the PCII for my normal riding. (I didn't see much point spending $500 on a dynotune when most of the tuning's done at full throttle, which I've almost never used!) I'd found out for myself that the "must do" things like disabling the PAIR valves and flapper actually made the bike perform worse on the street when riding sanely. I don't know whether the Unifilter is better or worse than stock, but I must say I don't like cleaning or oiling it, and making it in the first place was more because I *could* and already had the foam, the cleaning spray and oil, so it cost nothing. However, I initially went with Uni's suggestion that riding it on the street I could get away with not oiling it, then oil it if it wasn't catching all the dirt. Guess what? I ended up with a significant amount of fine grit on the wrong side of the filter. :unsure: Needless to say, it's not oiled. With all that tacky oil on it, I doubt very much whether it would flow more than a stock paper element, so it's on the cards that sometime I'll replace it with an OEM one (or maybe BMC - I've not yet decided). However, all the independent tests I've read say that the paper elements are best for both filtration and for performance both when clean and dirty.

[Ryanme17]

This is a interesting read.

http://www.rc51.org/airfilt.htm

I believe that because bikes don't have an airflow meter like cars do, they have no way of compensating for changes in incoming air as it corresponds to throttle position. This would also include altering the airbox. This is where a PCV with Autotune shines.

Interesting indeed. The point about stock filters flowing more air than the engine can use is a good point. filtration area on the stock filter is bigger than what I've seen on some 4-ish liter car engines. Granted you need a lot more air at the 11,500 RPM redline than the 6,000 RPM redline on a car, but still, if a smaller filter is good enough for an engine with 5 times the displacement...

[Guest]

Snap! I`ve got the pipercross filter and works great, the filter goes right to the edges. Bit faster on the pick up too! I`ve opened up the top airbox cover which makes a much bigger difference and induction sounds awesome. Started off with with flapper and snorkel mod, and just had to take it further! Recommended!

Danny:

Got any pics of your airbox mod? I've heard a lot of good stuff about Pipercross filters.

BTW all, BMC actually makes two filters for the VFR. A standard street filter and a racing filter. I have to assume the racing filter has a larger flow area.

Pete

Hey Pete, haven`t put them up on my profile, but here`s the first pic I got of my new air box before it went back on.

P1715_30-09-09.JPG

[Muff]

I never thought about the fact there is no intake air sensor. Now this discussion makes sense to me. Thanks for all the posting and giving me something to think about.

[Maddog Hoek]

Snap! I`ve got the pipercross filter and works great, the filter goes right to the edges. Bit faster on the pick up too! I`ve opened up the top airbox cover which makes a much bigger difference and induction sounds awesome. Started off with with flapper and snorkel mod, and just had to take it further! Recommended!

Danny:

Got any pics of your airbox mod? I've heard a lot of good stuff about Pipercross filters.

BTW all, BMC actually makes two filters for the VFR. A standard street filter and a racing filter. I have to assume the racing filter has a larger flow area.

Pete

Hey Pete, haven`t put them up on my profile, but here`s the first pic I got of my new air box before it went back on.

P1715_30-09-09.JPG

Other than probably a sweet induction sound, what other benefits have you gotten from this mod(mileage, response)? How easy was it to make? Did you lift the tank to increase air volume? Let me know, this looks like it definitely improves air volume!!

[coderighter]

Snap! I`ve got the pipercross filter and works great, the filter goes right to the edges. Bit faster on the pick up too! I`ve opened up the top airbox cover which makes a much bigger difference and induction sounds awesome. Started off with with flapper and snorkel mod, and just had to take it further! Recommended!

Danny:

Got any pics of your airbox mod? I've heard a lot of good stuff about Pipercross filters.

BTW all, BMC actually makes two filters for the VFR. A standard street filter and a racing filter. I have to assume the racing filter has a larger flow area.

Pete

Hey Pete, haven`t put them up on my profile, but here`s the first pic I got of my new air box before it went back on.

P1715_30-09-09.JPG

Now someone correct me if I'm wrong here, but since this is a 4 cylinder 4 stroke engine, doesn't the air box opening have to support one cylinder fill at a time? Aren't the 2 existing holes in the cover 3 to 4 times the size of the individual throttle bodies? The openings are designed to maintain velocity at low speeds, that's the main reason for the flapper valve on the second opening (I know it lowers the noise too). The snorkel also helps maintain low speed velocity. Even if this did add some air at high RPM, full throttle, the bike has no way of knowing (no airflow meter like a car) that it needed to add fuel, making the bike even leaner. You could fix lean with a Power Commander, but you couldn't fix the low end power loss caused by destroying low speed air velocity. However, that being said, it sure looks cool.

Side note: I always thought it was cool that Honda thought enough to add that little wall in front of the forward most screw holes to help prevent you from dropping the screws into an area that would be very hard to recover them from.

[Guest]

I have always used a K&N on the Nighthawk.

I don't really think of air filters as a performance mod, although on a really minute level maybe they are.

I can't imagine how many OEM filters I would have bought over the 18-years/55k-miles compared to the one K&N I have bought.

And come to think about it, I'm still on my original can of filter lube, and I always have Dawn dish detergent in the kitchen.

[Guest]

Sweet induction sound indeed! As for the mileage, I`m still getting a few more numbers to find out just how much more or less I`m getting through. In terms of a fair test, I`m one massive variable! Induction noise is awesome and I`m riding it harder at every opportunity but as soon as I get some figures I`ll post em up for all.

The tank was raised when I fitted it but back down again now. I`m waiting for the rain to clear before she goes back up again and can test it all how I`d like it to. I took it off after the first couple hundred miles and no problems with water getting in (as far as I can see). I think it may have leaned it up very slightly but with the PAIR back in, I think that (in theory) it`s compensating ok for now. I`ve got a few more bits I wanted to do before she goes back to the cell for a run. I`ve got the plots from before for a direct comparison so should be interesting. Worst case, sounds awesome!

[enzed_viffer]

Side note: I always thought it was cool that Honda thought enough to add that little wall in front of the forward most screw holes to help prevent you from dropping the screws into an area that would be very hard to recover them from.

No, to prevent YOU from dropping screws into an area that's VERY hard to recover them from; they didn't work for me. :cool:

But (however!) I only dropped two (2), or 3 (three) if you count dropping the same one twice. :rolleyes:

Obviously, Honda's celver engineers weren't clever enough to make it totally dumbarse proof....

[gstanfield]

I find it interesting that on my 30yr old CB400 they designed it so that you cannot drop a screw, even if you wanted. They are held onto the lid with little washer type retainers that let you unscrew them, but not remove them. This lets them stay in the lid and prevents dropping hardware. The hting is, on this old bike you could drop them all day and still not be an issue as they just fall though and hit the ground.

Oh well, so much for progress.

George

[Beck]

Snap! I`ve got the pipercross filter and works great, the filter goes right to the edges. Bit faster on the pick up too! I`ve opened up the top airbox cover which makes a much bigger difference and induction sounds awesome. Started off with with flapper and snorkel mod, and just had to take it further! Recommended!

Danny:

Got any pics of your airbox mod? I've heard a lot of good stuff about Pipercross filters.

BTW all, BMC actually makes two filters for the VFR. A standard street filter and a racing filter. I have to assume the racing filter has a larger flow area.

Pete

Hey Pete, haven`t put them up on my profile, but here`s the first pic I got of my new air box before it went back on.

P1715_30-09-09.JPG

Other than probably a sweet induction sound, what other benefits have you gotten from this mod(mileage, response)? How easy was it to make? Did you lift the tank to increase air volume? Let me know, this looks like it definitely improves air volume!!

I still keep thinking that the induction system still has ultimate capacities determined by openings more downstream on the induction system, from the aggregate size of the opening at the filter itself to the size of the throttle bodies then valve sizes, profiles and angles. In the end you hit a limit of returns with simple mods which can maybe only be overcome by forced induction systems like a supercharger or turbo. That's why most of these "no cost" quicky mods have very minimal or no affect to the performance of the engine unless the engineer handling it's design at Honda just totally flubbed the induction system design to start with. Easiest solution for more power on some VFRs is the Torocharger route. It does cost much but not as much as the probable price of the new 1200cc V4 that's coming out.......plus i don't think you hit that 600 pound mark with it

Beck

95 VFR

[Guest]

I still keep thinking that the induction system still has ultimate capacities determined by openings more downstream on the induction system, from the aggregate size of the opening at the filter itself to the size of the throttle bodies then valve sizes, profiles and angles. In the end you hit a limit of returns with simple mods which can maybe only be overcome by forced induction systems like a supercharger or turbo. That's why most of these "no cost" quicky mods have very minimal or no affect to the performance of the engine unless the engineer handling it's design at Honda just totally flubbed the induction system design to start with. Easiest solution for more power on some VFRs is the Torocharger route. It does cost much but not as much as the probable price of the new 1200cc V4 that's coming out.......plus i don't think you hit that 600 pound mark with it

Beck

95 VFR

Not far off Beck! I`d agree that there`s minimal gains to be had, but as soon as I saw the standard box, flapper and snorkel, something had to be done! I`m a fan of breathing's best and I had thought about the charging route, just not yet, so for now, intake, exhaust and management for me!

[CandyRedRC46]

pipercross vs kn vs bmc vs oem

in that order:

and finally all that bmc quality, after 30,000 miles... no they are NOT lifetime filters, nor is there any warranty.

[mello dude]

^^^ Jeez - I'm gonna inspect mine. --

- Gotta source for pipercross?

[Bassie]

You guys put oil on filters? I have never done souch a thing, why are you doing that?

Doesn't that hurt the airflow?

[CharlesW]

You guys put oil on filters? I have never done souch a thing, why are you doing that?

Doesn't that hurt the airflow?

The filters being oiled are designed to be used after oiling.

K&N being one of the best known.

http://www.knfilters.com/

DON'T oil a conventional paper pleated filter.

[Dae]

K&N has a more efficient matierial for filter, hower the total area of the filter media is smaller so its a wash. However economically mine has paid for itself 3 or 4 times over, cleaning and reoiling is a snap and I dont have to waste my time taking a trip or spending time ordering a new oem one when it gets clogged up. Paper is fine but until sombody figures out a way to reuse it well enough the K&N is worth the money.

I use a K&N in every engine I own. Just for the money savings. Your noy going to get more power even if you run no air filter. If you do it will be so minor there is no diffirence.

Fact. K&N filters flow better once they get a little dirty.

LIke I said, it just saves money. A stock filter is $45, a K&N is $50 and you never have to buy another, pretty simple math, just dont expect 10 horsepower. Maybe more like a 1/10th of a HP.

I have never seen a dyno sheet from just an air filter that did much. My wifes car does seem to breath a lot better at high rpm's. More air with no more fuel equals nothing.

I thought dirty filter has more restriction compared to a new filter, hence replacing or cleaning filters such as K&N.

I'm still using my original filter, inspecting it every 15,000KM. I just tap and use compressed air and if the filter looks good I just reuse it. I currently have 67,000KM on my 1200.

Tried K&N for about 8,000 KM on this bike and didn't like dirt entering my airbox,compared to stock air filter. If you hold up a K&N air filter under a light you will see pin size holes and can see how dirt will enter the airbox.