K&N filters power ratings

[ToneTheMoan]

Just got these useful figures from K&N in the UK right.... 1. BU-9003 (oem replacement) can flow enough air to cope with up to 200 BHP.....2. RA-077V (used by nicholas900 and SEXT9) can flow enough air to cope with up to 146 BHP..... 3. RX-4010 (as used in FAST kit) can flow enough air to cope with up to 189 BHP.... Hope thats of some use to somebody!

 

[TeamHennis]

Thanks Tone. Did you notice any changes (positive or negative) by swapping to the RA-077V? I saw where SEXT9 stated he didn't notice any changes, but I just wanted another opinion before I do the swap myself.

 

[ToneTheMoan]

No it was all just exactly the same but not tried it flat out yet! mine had the velocity stack and the airbox "nipple" but losing all that made no difference so i wonder if they fitted all that to try and get better airflow due to the restrictive double airbox etc but thats just my opinion its not fact! lol i just mounted the RX-4010 filter and it sounds even stronger with an even more stable tickover but i wont be able to road test it for ages yet but it sounds very promising! but the RA-077V is without doubt a good filter in my opinion! With both filters i fitted them directly onto the manifold with some heat shield under it like the special ops one but not as well made! Mate what i wouldnt give to get my hands on one of those FAST kit heat shields!! just name your price! seriously!!

 

[nicholas900]

So your saying I have room to grow? Sweet .

 

[SEXT9]

I maybe wrong. But, I'm of the opinion the only reason the stock air filter is the size and shape it is, is so that they could fit everything inside of it. They crammed a velocity stack, 2 breather tubes, and a sensor in. When you do the breather reroute, you don't need the extra space inside the filter.

I also think it looks like when Buell designed the system, the left side scoop could've been what was envisioned as a RAM air setup. Hence, the size of the air box overall. However cooling became more important. And in the later years, the hole got blocked off for more fuel capacity. There really wasn't a need a redesign the entire air box. Simply modify what is already there.

I'll be interested to see if Tone's bike performs any differently. Mine made no difference in performance at all. I do have the EBR Race kit which was designed with a K&N filter in mind. So, I just see the filter vibrating under the cover at idle is all. Once you get off idle it sits there smoothly. I'll only go back to the stock setup if I sell the bike or I feel nostalgic.

 

[Chicknstripn]

Im sure someone will correct me if I'm wrong on this one but I do believe removing the velocity stack adversely effects performance. I think ASB or those dudes from the Netherlands did dyno runs with and without the velocity stack. Without negatively effected HP and torque.
Also the spot on the frame near the left scoop that looks like it was "covered" up on the frame was hollow in the earlier models.
I may stand to be corrected on this one, AGAIN, but I believe Eriks original intent was to develope a production turbo xb. That "hole" in the frame was designed for the extra turbo plumbing.
Least that what I heard or read somewhere many years and beers ago.
Please correct me if I'm way off on this

 

[Chicknstripn]

Found this on frame
http://www.buelletinboard.com/forum...e-Erik-Buell-comments-on-Buell-Turbo-History!

 

[Chicknstripn]

Found this on stack
http://www.nrhsperformance.com/tech_xbvelocitystack.shtml

 

[ToneTheMoan]

Thanks chickn thats all really good stuff to know and it does look like another of those personal experience "grey" areas, i wonder if it makes a difference that it was a 2003 model so maybe more critical? i wish someone could do this for 2009 models and see how that pans out? the weird thing is that my 09 SS running the "FAST" K&N filter has never felt stronger, smoother or more stable before but then i am no Valentino Rossi so may not notice if i lost a couple of horsepower but from a purely personal point of view mate it feels GOOD!!

 

[ToneTheMoan]

Sorry nicholas and SEXT9 just saw your posts! nicholas oh yes mate your bike can still grow and flourish! lol and SEXT9 so far no problems i settled on the "FAST" filter in the end and squeezed the IAT in there too! it coughed and spluttered to start with then 10 minutes later was as smooth as ever! i have the IDS "race" ecm on mine and mate i know what you mean about the filter vibrating! i use it to shake rattle cans now!! ha ha ha also mine has the side of the airbox vented now so dont know if that may help?

 

[ToneTheMoan]

Right so one last question chaps! Does the inlet pipe between the filter and the manifold need to be completely straight or could i offset it by 1/2" or even angle it at 15 degrees from upright? i figure as long as its a smooth flow with no kinks it should be ok? this sort of follows on from the stack removal question and what your thoughts are on air flow because the way i see it is at the end of the day you have a set size inlet flowing air through a filter and an engine can only swallow as much as the inlet size allows but it all comes back down to how important really are inlet pulses and swirl etc on a road bike? what are your thoughts? if i need to i will have to risk it anyway and then report back if my bike is still in the shed or in several buckets!! ha ha ha