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Author Topic: Busa air box or not  (Read 11462 times)

Offline Isleofmanbusa

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Busa air box or not
« on: February 16, 2016, 02:32:19 AM »
I run a 1441 nitrous slick and bar  Busa 445 415 Web cams ect my question is I've done all the airbox mods but do I need a airbox at all Im sure ram air makes no diffrance because I run nitrous can I run without a airbox with no loss of power
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Offline Isleofmanbusa

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Re: Busa air box or not
« Reply #1 on: February 18, 2016, 05:35:56 AM »
Any one
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Offline RansomT

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Re: Busa air box or not
« Reply #2 on: February 18, 2016, 07:44:38 AM »
It's not just the ram air effect, but the airbox is designed with Helmholtz principals (I think those are the principals).  These are resonance principals that use pressure pulses within the box to increase HP.  You can modify the airbox to move the effect higher in the RPM band, e.g. shorter velocity stacks, but I wouldn't think removing the entire box would be a good idea.
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Offline fvance

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Re: Busa air box or not
« Reply #3 on: February 18, 2016, 01:15:36 PM »
To the best of my knowledge it would be a bad idea.
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Offline MJ Williams

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Re: Busa air box or not
« Reply #4 on: February 18, 2016, 08:05:35 PM »
Can't speak to the Hayabusa but back in the day we would take the air box off of our roadrace bikes and fit open velocity stacks to "get more power" and ended with something that worked well within about a 1000 rpm range. It was like an on/off switch between fouling plugs, too lean or running well but the dyno did show better numbers. Of course it went slower on the track.
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Offline Isleofmanbusa

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Re: Busa air box or not
« Reply #5 on: February 19, 2016, 01:41:58 AM »
Ok this all makes sence but what I don't understand is there are a couple of guys that run the same set up as me except thay run 48mm down draft Lectrons with no air box would thay not run better with a air box then smooth air less turblance ect sorry if I'm being a bit thick I just need to understand it thanks for all your help so far
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Offline MJ Williams

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Re: Busa air box or not
« Reply #6 on: February 19, 2016, 04:06:50 PM »
It would be an assumption for me to speak without doing and seeing in the Lectron example but if you look at the money spent in airbox design of any high dollar NA racing series  (old F1, pro stock cars, sports cars, Moto GP) that is good enough for me.
Comparing a road track application and a drag race application where you are pouring nitrous down its throttle may not be a fair comparison though.
Have a Harley, spent lots of money on it, thought I had a fast motorcycle, bought a Busa, realized all I had was a fast Harley, not a fast motorcycle!

Offline 396

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Re: Busa air box or not
« Reply #7 on: February 19, 2016, 10:16:11 PM »
The air box was designed with the stock motor in mind. On a heavily modified motor the air box can cost HP. Now if you can get a bigger box to fit on the bike, then that is a different story. Again, this is on a heavily modified motor.

Offline Landspeed Larry

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Re: Busa air box or not
« Reply #8 on: February 20, 2016, 01:17:12 PM »
The stock airbox with the usual modifications is darn good. Many years ago we ran a mile bike with lectrons and it performed about the same as the stock FI . It is not too small except perhaps at the hit when a large engine gulps more air  AirTech makes a larger one but I don't think a 1441 would need it.  The problem is the head, the intake ports are too long for maximum peak power. Carpenter Racing has developed a short port (They mill off the stock intake and install a plate to mount the TB's without boots) that extends power an additional 1000 RPMS. But Speed costs  $$ so check it out on his site. And even the stock 46mm TB's work well. How about 254 mph on a 1700cc Busa with stock intake ports and stock airbox ( no nitrous).  LSL
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Offline fvance

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Re: Busa air box or not
« Reply #9 on: February 20, 2016, 08:01:54 PM »
Can't argue with that!
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Offline Isleofmanbusa

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Re: Busa air box or not
« Reply #10 on: February 27, 2016, 01:22:03 PM »
Well it was dyno time today .to see weather I have wasted my time or not with setting my busa up to run without a air box and it all went well a lot of fueling changes needed to be made but all good no loss of torque at any rpm.and picked up a few HP I think my 1441 big cam motor likes no air box 229 bhp just motor so 4 weeks time will see how it is on the track
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Offline RansomT

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Re: Busa air box or not
« Reply #11 on: February 27, 2016, 02:21:03 PM »
How much change did you see?

And my hats off to you for actually taking to the dyno to check.
« Last Edit: February 27, 2016, 02:23:04 PM by RansomT »
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Offline 396

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Re: Busa air box or not
« Reply #12 on: February 28, 2016, 11:04:09 PM »
Told you!

Offline Isleofmanbusa

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Re: Busa air box or not
« Reply #13 on: February 29, 2016, 12:31:55 PM »
Well the motor picked up 4bhp and strangle gained mid range torque but the same max figure no loss of power any were in the rpm  range so my plan seems to have worked loads more room under the shell looks a lot neater  an other strange thing whitch was not expected was with the  nitrous pull on the dyno normal the power starts to drop off at 10500 rpm but now it just keeps climbing not a clue why .so to recap the airbox I was running was as modified as a busa air box could be no filter just mesh all the floor removed and rebuilt so a fairly high flow airbox and back to back tests with this air box and a stage 2 moddedicated air box was massave 10 bhp loss with stage two modied  box I think the up shot is my motor 1441 big cams big ports big exhaust  just wants lots of air and no box at all it just loves it
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Offline 396

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Re: Busa air box or not
« Reply #14 on: February 29, 2016, 03:58:15 PM »
Saw the same thing years ago on the dyno. Large box mod versus no box and the large box mod killed it. I am sure it has to do with the head and cams. I had BIG cams also.

Offline RansomT

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Re: Busa air box or not
« Reply #15 on: February 29, 2016, 05:22:01 PM »
Now, I have seen on the +1441 motors that a stripped wiremesh only filter versus BMC filter netted a 3-4 HP loss across the board.  It really doesn't make logical sense, but it does show up that way.

With my HC 1340 motor I am building, I may just try no box versus large box mod w/BMC on the LSR track to see if the ram air makes that much difference.
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Offline 396

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Re: Busa air box or not
« Reply #16 on: February 29, 2016, 05:35:01 PM »
Again depending on your combo,  i am sure  the airbox would would help, especially with a LS bike. The ram air should net you some big gains. I would have loved to use a airbox with my combo, but It just killed it with the stock sized box.

Offline Isleofmanbusa

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Re: Busa air box or not
« Reply #17 on: March 03, 2016, 02:01:24 AM »
I'm sure you will gain a bit from ram air but ram air is not in the equasion for me as I run nitrous and the motor gets all it wants from that
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Offline Isleofmanbusa

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Re: Busa air box or not
« Reply #18 on: March 18, 2016, 03:13:57 AM »
Well just to report back I was at the track with the bike last weekend (santa pod) and all went well no problems at all came off the line well too step and launched spot on full throttle 5500 rpm no problems at all and that's with no gas until 1sec out 60fts no diffrant and the rest of the pass well good so I'm really pleased no losses in fact slightly quicker so Im pleased loads of room under the bodywork without the airbox my wet nitrous system nice and neet 
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Re: Busa air box or not
« Reply #19 on: March 18, 2016, 04:55:21 AM »
Looks great!
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Offline Isleofmanbusa

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Re: Busa air box or not
« Reply #20 on: March 22, 2016, 03:51:21 PM »
Thank you
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