A question re: AIRFLOW

jdsbusa

jdsbusa

Registered
Ok, for those with an engineering degree or someone very in the know about engines....

I had my bike apart today doing some fall cleaning to it, installing a new air filter, cleaning the ram air ducts out, etc.....and was curious about something. I've read from a multitude of threads that the OEM filter is definitely the way to go which is what I've always used. Today I cranked my air compressor regulator all the way up pushing almost 200PSI through a large nozzle air chuck. It's similar to a leaf blower in terms of the massive amount of airflow it pushes (good for cleaning the garage floor of these dang fall leaves that blow in every time I open the door). At any rate, I'm feeling the air coming through the filter and must say it's pathetic....or at least feels that way. Seems extremely restrictive. I then fire the bike up with the filter out and put my hand near the tunnels to feel how much air they suck when throttled up. At about 6k the suction is pretty impressive. So I'm curious, just how restricted are our poor little Busas with the necessary evil of a filter? Obviously a turbo would take care of a lot of this bottleneck, but has anyone dyno'd a bike with no filter and seen what the actual difference is? Of course the "ram-air" effect wouldn't take place on the dyno but between the quite small opening in the air box and the filter just how much HP is being sucked out of the engine??

Just curious.... :whistle:
 
Your bike will always have air restrictions as long as its got a air filter on it. If it was safe to run a motor with no air filter everyone would be doing so. But I agree, our Busa's are restricted in many ways and that's one of them. The filter can be a good and a bad thing. As for running the bike with no air filter and no ram air effect, I don't think it would make a difference. :whistle:
 
I never really thought about how restrictive it was....or never noticed it. I worked on automotive engines for 15+ years but the air cleaner is much bigger and seemed to flow better back then (likely due to inferior filter media). I'm sure someone has dyno'd without a filter to prove or disprove this theory....just curious as to who has done it and what the result was. :beerchug:
 
Leave the filter out and suck dirt through the engine and ruin the bore, etc., etc. and probably have zero gains. Just read an interesting article yesterday about the design of these systems and how they work with the bike.
 
No one said a thing about riding it with the filter out....I asked about HP gains without a filter on the dyno sans ram-air effect. :thumbsup:
 
Try your experiment again with the filter in and your hand over the air inlet while the engine turns 6k or more r.p.m. I suspect you'll find no significant difference in suction from what you found when the filter was out.

As for blowing air through the filter and observing little passing through the other side, I don't think many air compressors out there are capable of moving as much air as a 1340 cc engine turning 10,000 r.p.m. If my quick math is correct, that works out to about 120 cubic feet per minute of air being sucked through the sealed airbox system.
 
F=MA said:
Try your experiment again with the filter in and your hand over the air inlet while the engine turns 6k or more r.p.m. I suspect you'll find no significant difference in suction from what you found when the filter was out.

As for blowing air through the filter and observing little passing through the other side, I don't think many air compressors out there are capable of moving as much air as a 1340 cc engine turning 10,000 r.p.m. If my quick math is correct, that works out to about 120 cubic feet per minute of air being sucked through the sealed airbox system.
Click to expand...

Impossible to try that, once the filter is in place the runners are blocked off. :laugh: I'll just accept the theory that the filter flows enough.....but obviously a turbo would flow a heckuva lot more like I want. :thumbsup:
 
the filter is just dispersing the air flow.. not a thing wrong with that..

hard pressed to find the hp to justify the cost of a $90 air filter..
 
i've had mine dyno b4 with and then without with a modded airbox picked up about 5hp on stock motor with muzzy pipe pair valve and crank balancer removed and power commander i made 172hp pretty decent knowing i havent gone inside the motor til now
 
so are the standard filters better than say a bmc witch is what im running, i have a small flat spot low down could this be part of the reason .
dont mean to thread jack sorry :whistle:
 
my buddy had his zx14 on the dyno,made 6 more hp with out the filter and that was a kn filter. the dyno man said the kn always makes less power that stock filters on the dyno, I"ll never buy another one. same thing with oem clutches, all reports I"ve gotting say they out last any after market clutch. I ran an A.P.E. clutch pack last time, it was a monster for about 45-50 passes then went up in smoke:whistle: I"m going to try an FBG this time, if it dont last I"m going back to oem.Oh sorry about hacking the air flow:laugh:
 
dragonbusa said:
my buddy had his zx14 on the dyno,made 6 more hp with out the filter and that was a kn filter. the dyno man said the kn always makes less power that stock filters on the dyno, I"ll never buy another one. same thing with oem clutches, all reports I"ve gotting say they out last any after market clutch. I ran an A.P.E. clutch pack last time, it was a monster for about 45-50 passes then went up in smoke:whistle: I"m going to try an FBG this time, if it dont last I"m going back to oem.Oh sorry about hacking the air flow:laugh:
Click to expand...

Bike has to be tuned to run properly with bmc or k&n:rulez:. the bikes is "TUNED" from Suzuki to perform with a stock filter, so yes, adding an aftermarket without proper mapping could result in lower performance #'s:poke:
 
First thing i did to my 08 was to add a K&N. I just wanted a reusable filter, I didn't expect any gains. Of course you could not feel any hp increase, but I was suprised that the off idle throttle response was noticeably much better.
 
Filters are rated for flow restriction at rated airflow. Here in the States, you measure "inches of water" vs. cubic feet per minute (CFM) of air.

You also measure filtration performance, where you determine the percentage of contaminants removed at a given size of particle.

K&N filters typically flow with lower restriction (inches of water) than a conventional paper filter, but they also don't have as good filtration properties either for very small particles.

Now that we're past all that technical mumbo jumbo, I suggest you check out the way cool system from Lord Humongous if you really want the best performance for your Busa. :rofl:
 
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