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I BMC has one

my buddy at the shop called me and said its in stock if I wanted it installed yet

but i dont want to put it in yet untili have the full system installed and Power comander
 

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If you guys look down where I posted in the Big Valley Honda section you will see that Bob H says the air filter mods made huge increases in hp.
He even said in testing the Moriwaki systems with PC and air filter the bikes were making 166-167 hp at the wheel!!
 

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michaelrc51 said:
If you guys look down where I posted in the Big Valley Honda section you will see that Bob H says the air filter mods made huge increases in hp.
He even said in testing the Moriwaki systems with PC and air filter the bikes were making 166-167 hp at the wheel!!
Is the filter mod the same as on the RC51, where you cut away the metal mesh part around the filters? For 2 hp I'd be happy to do that free mod. Also, is it possible to do a flapper mod on this bike? This has something similar to the RC51 also, where different intake ports open and close at different rpm.
 

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crotch rocket
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I think about the only aftermarket filter people knew about was the K&N; & I've heard the OEM is usually better simply because they're more consistent in production than the K&N (real PiTA when setting up the fuel jets). I hadn't heard of BMC air filters before I joined this forum, but it sounds like they may be superior to the OEMs.
 

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RRRIDER said:
Well I went out and launched mine without a filter, and It felt a hell-of-a-lot better. Lot more low end. I might just make a pull on the dyno just for comaprison sakes.

What type of damage could happen from running without a filter? Did you put something in place of the filter?
 

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crotch rocket
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I checked out BMC's website. Looks like they're similar to the K&N's: cotton instead of paper; wash & re-use.

Anyone know the difference between the standard & a race versions? Technically, most of our exhausts are not for street use--is it OK to use the race version of the BMC filter for our street bikes?
 

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I cut the chicken wire off of my air filters. Man what a difference!! It had 2 layers of chicken wire wrapped around a normal filter. My SOMP dyno says at least 5 HP up. I can really feel the difference down low plus it makes the throttle more crisp. Highly recommend doing this free mod.
 

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Unless someone can show me that the engine can use more air than the stock filters can flow I doubt any real gains can be expected. Saying bmc filters give a hp gain when an exhaust an pc was added at the same time doesn't mean the filters made any difference . It is more likely the exhaust and new map is where the additional power came from. Just my oppinion.
 

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sam said:
Unless someone can show me that the engine can use more air than the stock filters can flow I doubt any real gains can be expected. Saying bmc filters give a hp gain when an exhaust an pc was added at the same time doesn't mean the filters made any difference . It is more likely the exhaust and new map is where the additional power came from. Just my oppinion.
That isn't an opinion, it's the damn truth!
 

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Discussion Starter · #15 ·
get_dude
I did cut some screen a little larger than window screen, and fitted in place of the filters so no rocks (etc)could make its way inside. I don't street ride this bike much at all, if I did I put the BMC's or K&N's.
It felt real good I'll see this weekend when I get to the track. :D
 

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Modified air filters

given that Honda sets the FI map for the stock filter, you will be running lean with any mods. The throttle will seem much crisper and it will feel like more power. A dyno will show otherwise. Unless you are remapping it is foolish to modify the air filter. Even closed loop systems ( and I dont think the RR is closed loop) only modify the Fuel air mixture in certain locations.

The worst case scenario for lean running is to run so hot the piston material melts and you find it on your spark plugs (this is before the engine seizes). In other words, modifying the air filter without adjusting the fuel air ratio is a big mistake.

I run one race bike with velocity stacks and flatslides, no air filter. Great power, mediocre longevity. I usually leave stock filters in, they actually filter out all the crap that ruins an engine.

On the R6 yammie (sorry) the aftermarket filters consistenly made less dyno power than the stock filter.

Ernie
 

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Re: Modified air filters

ernie said:
given that Honda sets the FI map for the stock filter, you will be running lean with any mods. The throttle will seem much crisper and it will feel like more power. A dyno will show otherwise. Unless you are remapping it is foolish to modify the air filter. Even closed loop systems ( and I dont think the RR is closed loop) only modify the Fuel air mixture in certain locations.

The worst case scenario for lean running is to run so hot the piston material melts and you find it on your spark plugs (this is before the engine seizes). In other words, modifying the air filter without adjusting the fuel air ratio is a big mistake.

I run one race bike with velocity stacks and flatslides, no air filter. Great power, mediocre longevity. I usually leave stock filters in, they actually filter out all the crap that ruins an engine.

On the R6 yammie (sorry) the aftermarket filters consistenly made less dyno power than the stock filter.
Agree, 100%. When people refer to BVH air filter mod gains, you should note that they had also PCIII and I believe all the results are with proper mapping. As forry yammie filter, my dyno operator told the same thing last friday, they had mapped European Championship Supersport R6 last summer and found the stock filter to be best (they did more than 300 dynoruns with different configs).
 

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Some of you guys need to quit... Too many experts in here. I bet half you guys speaking up have never even actually operated a dyno or done any real testing on this subject.

Most of the time the ECU's are way too rich from the factory & just slapping some higher flowing filters on them is not going to alter the A/F ratio enough to even remotely say that it is too lean... The real problem with high flow filters is changing the resonance or introducing turbulence into the airbox which can stall the airflow

I don't have time to go all into it right now, but read this article I wrote

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

Finally, I am running BMC race filters in the RR right now & while I usually do not condone using aftermarket highflow filters for the reasons mentioned above & in my article, I do believe they are a good mod for this particular bike.
 

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Lord Duckhunter said:
Some of you guys need to quit... Too many experts in here. I bet half you guys speaking up have never even actually operated a dyno or done any real testing on this subject.

Most of the time the ECU's are way too rich from the factory & just slapping some higher flowing filters on them is not going to alter the A/F ratio enough to even remotely say that it is too lean... The real problem with high flow filters is changing the resonance or introducing turbulence into the airbox which can stall the airflow
Not trying to question your expertize with this (the articles you've written are just awesome) as I'm one of those that have never operated a dyno, but at least PCIII "completely stock bike" map for euro-1000RR is adding juice between 6000 and 8700 rpm pretty much regardless of the throttle position (up to 20 "units"), which would indicate that stock bike is already lean in that (quite much used) area. I've also looked through lambda readings from my own bike when it has been dynoed (my 1000RR already has been to two different dynos in 3 different configs) and seen the same thing. I would quess that high-flow filter would amplify this in a completely stock bike. I have no idea if high-flow filter would make the stock bike "too lean". How much is dangerously "too lean"? Will ram-air amplify the "problem" or will stock ecu compendate this? I'd quess that stock ecu can compensate ram-air effect for stock filter...

Like said, not trying to be smartass here, just trying to learn more about this stuff.
 

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Sorry in re-reading my post it came out different than I had intended as I didn't mean to come off sounding pissy.

The ECU does compensate for the ram-air effect, but does it with the speedo sensor.

Yes there are some lean spots here & there usually put into the mapping at certain rpms to pass EPA (or your country's equivalent) emissions & noise abatement testing, but for the most part usually bikes are too rich throughout most of the rev range

Regardless though of the base mapping in the ECU being rich or lean I just do not think that there will be any problems with the BMC filters. If you look at the BVH chart with the filter mod there is virtually no change at all to the graph except at the top end. Of course that in itself is totally inconclusive as well as the stock filters with or without mesh are still going to have very drastically different flow characteristics since they have different opening sizes & the BMC's don't use the stock plastic seperators that guide the air that the stock filters have. Again I have not done any testing on the dyno yet & simply cannot give details, but my strong speculation is that the tuning of the airbox on this bike just lends itself to this kind of mod whereas most of the time they don't.
 
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