Air intake options

[BusaTransplant]

So I have more Busa custom aftermarket questions. I’m putting a gen1 engine in a different bike frame and wondering what experience everyone has with compact air intakes for these engines. What has worked, hasn’t worked, all advice appreciated! (just don’t tell me not to do the swap )

 

[kim windsor]

You are looking at the best intake system that comes with the Hayabusa
it is designed on volumetric ,and ram air affect and can’t do better unless you go bigger ,and then it my be to big ! Just saying read some books on flow mechanics.

 

[BusaTransplant]

You are looking at the best intake system that comes with the Hayabusa
it is designed on volumetric ,and ram air affect and can’t do better unless you go bigger ,and then it my be to big ! Just saying read some books on flow mechanics.

I understand that but the bike frame this engine is going in does not have space available to fit a factory air box in.

 

[sixpack577]

Pod filters will work, the ecu can be flashed on 02-07 gen1s(99-01 can be upgraded to 02-07 electronics)
and ram-air compensation can be turned off(adds fuel at high rpm).

 

[BusaTransplant]

Pod filters will work, the ecu can be flashed on 02-07 gen1s(99-01 can be upgraded to 02-07 electronics)
and ram-air compensation can be turned off(adds fuel at high rpm).

That’s something I’m considering(although this also makes it difficult to mount the IAT), trying to brainstorm an option to get the filters into some cooler fresher air before I commit to individual pods though. (I’ve seen filters setup like a short ram but unsure of a best solution similar to that for 4 TBs)

 

[202mphbusa]

I understand that but the bike frame this engine is going in does not have space available to fit a factory air box in.

What’s it going in? Totally just curious. You don’t have to answer

 

[sixpack577]

I think any type of custom ram-air setup would work well enough.

 

[BusaTransplant]

What’s it going in? Totally just curious. You don’t have to answer

A 1980 GS850G. I’ve started test fitting the forks, ordered the bearings today.

 

[BusaTransplant]

I think any type of custom ram-air setup would work well enough.

I respect that. I know meeting the engineering put into the busa’s performance will be next to impossible without oem equipment for the most part. I’m just looking for a feasible compromise. Running the IAT with pods isn’t exactly accurate so just curious of options.

 

[sixpack577]

I respect that. I know meeting the engineering put into the busa’s performance will be next to impossible without oem equipment for the most part. I’m just looking for a feasible compromise. Running the IAT with pods isn’t exactly accurate so just curious of options.

Consider this, the airbox has some engineering for flow...and to fit the frame and gas tank.
The intake tubes? Yep, same...they fit the frame and nose.
The gen1 has 2 airbox mods too, small mod for untuned, big mod for air/fuel tune.
Restrictive? Yes, the airbox is.
What does the airbox need to be able to do? Basically hold a big enough gulp of air for any rpm and speed at any given time.
The airbox is 'pressurized' as soon as you start moving, as air begins to be forced into the inlets.
The real ram-air effect however, obviously needs a little more speed to be noticeable, but is more noticeable the faster you go.
In theory you could have a tuba for an inlet on each side, or a small scoop and make similiar numbers, as once you reach the maximum capacity the tubes and airbox can flow, then air is building up in front causing turbulence.
Factory tubes are also not air tight, and have drain holes for water.
Only Land Speed Racers seal them 100%.
There is more magic going on in the velocity stacks than the airbox.
As long as you have room for similiar volume of 'on demand' lightly pressurized air that a stock box would have, per your application(cool project) would be more than sufficient.
I would imagine the finished custom airbox equivalent to be a 4"-6" o.d plastic pipe with 4 holes, one per throttle body, and a ram-air tube coming out of each open end, with some type of small air filter in each tube.
Don't overthink it.

 

[BusaTransplant]

Consider this, the airbox has some engineering for flow...and to fit the frame and gas tank.
The intake tubes? Yep, same...they fit the frame and nose.
The gen1 has 2 airbox mods too, small mod for untuned, big mod for air/fuel tune.
Restrictive? Yes, the airbox is.
What does the airbox need to be able to do? Basically hold a big enough gulp of air for any rpm and speed at any given time.
The airbox is 'pressurized' as soon as you start moving, as air begins to be forced into the inlets.
The real ram-air effect however, obviously needs a little more speed to be noticeable, but is more noticeable the faster you go.
In theory you could have a tuba for an inlet on each side, or a small scoop and make similiar numbers, as once you reach the maximum capacity the tubes and airbox can flow, then air is building up in front causing turbulence.
There is more magic going on in the velocity stacks than the airbox.
As long as you have room for similiar volume of 'on demand' lightly pressurized air that a stock box would have, per your application(cool project) would be more than sufficient.
I would imagine the finished custom airbox equivalent to be a 4"-6" o.d plastic pipe with 4 holes, one per throttle body, and a ram-air tube coming out of each open end, will some type of small air filter in each tube.

So this is the bike prior to disassembly, I’ve also been thinking about adding louvers to these side plates on the air box. It would still add the air in prefilter and if it still fits in the same space after the Busa motor is mocked up, I was wondering if it might give enough air to keep up. Thoughts? Figure this factory box would hold the volume, offer space for the IAT, and if I can duct in enough air might work.

 

[sixpack577]

I respect that. I know meeting the engineering put into the busa’s performance will be next to impossible without oem equipment for the most part. I’m just looking for a feasible compromise. Running the IAT with pods isn’t exactly accurate so just curious of options.

Consider this, the airbox has some engineering for flow...and to fit the frame and gas tank.
The intake tubes? Yep, same...they fit the frame and nose.
The gen1 has 2 airbox mods too, small mod for untuned, big mod for air/fuel tune.
Restrictive? Yes, the airbox is.
What does the airbox need to be able to do? Basically hold a big enough gulp of air for any rpm and speed at any given time.
The airbox is 'pressurized' as soon as you start moving, as air begins to be forced into the inlets.
The real ram-air effect however, obviously needs a little more speed to be noticeable, but is more noticeable the faster you go.
In theory you could have a tuba for an inlet on each side, or a small scoop and make similiar numbers, as once you reach the maximum capacity the tubes and airbox can flow, then air is building up in front causing turbulence.
There is more magic going on in the velocity stacks than the airbox.
As long as you have room for similiar volume of 'on demand' lightly pressurized air that a stock box would have, per your application(cool project) would be more than sufficient.
I would imagine the finished custom airbox equivalent to be a 4"-6" o.d plastic pipe with 4 holes, one per throttle body, and a ram-air tube coming out of each open end, will some type of small air filter in each tube

View attachment 1644118
So this is the bike prior to disassembly, I’ve also been thinking about adding louvers to these side plates on the air box. It would still add the air in prefilter and if it still fits in the same space after the Busa motor is mocked up, I was wondering if it might give enough air to keep up. Thoughts? Figure this factory box would hold the volume, offer space for the IAT, and if I can duct in enough air might work.

That's what I was picturing in my head.
I think you can make that work very well.

 

[202mphbusa]

I would cut and mount as much of the airbox as you can
rebuild the rest of it around the bike

 

[202mphbusa]

and I don't think the airbox will end up ANYWHERE near where you drew
Busa motor is way more downdraft Airbox is gonna be somewhere above the OEM GS carbs
or am I missing something?

 

[fallenarch]

Maybe work with a B-King intake basic setup since it's sort of a naked? I think to make it work without considerable tuning and performance impacts the best way to go might be to cut that tank open so it's a shell and try to get a Busa or B-king intake under it. Then relocate the fuel.

Also, you are going to need to figure out how to reinforce that frame. A cradle frame will not handle the power of a Busa motor and will twist badly. If the airbox solution sacrifices the power some, that might be a good thing.

 

[Bumblebee]

So I have more Busa custom aftermarket questions. I’m putting a gen1 engine in a different bike frame and wondering what experience everyone has with compact air intakes for these engines. What has worked, hasn’t worked, all advice appreciated! (just don’t tell me not to do the swap )

Your last line in brackets is the right line to be using....this will be a pretty huge undertaking, you will have your hands full.

Have you mocked up the engine in the frame yet? That would be the first thing I'd be doing to see where everything is sitting..

 

[fallenarch]

Like this:

You could draw air on each side of the bike to get enough flow. You'll have to work out a fuel pump that will draw properly. Maybe make the tank and air box out of aluminum or CF if you have access to the skillsets.

 

[BusaTransplant]

Your last line in brackets is the right line to be using....this will be a pretty huge undertaking, you will have your hands full.

Have you mocked up the engine in the frame yet? That would be the first thing I'd be doing to see where everything is sitting..

Have not yet, was just sitting and thinking, and figured I’d see what successes people have had in modifying of building intakes before I tried to reimagine the wheel from scratch .

 

[Bumblebee]

Have not yet, was just sitting and thinking, and figured I’d see what successes people have had in modifying of building intakes before I tried to reimagine the wheel from scratch .

I think what you are doing is unique and perhaps never been done before (at least on this forum).

In order to get where you need to be, your engine needs to be in the frame so you know the clearances required. We would all be guessing at this stage.

I do know the Hayabusa engine is pretty dependent on proper air flow and pressures...messing with that too much will really affect how the engine runs.

 

[fallenarch]

Frankly, it might be easier to take a busa engine/frame and mimic the old GS look.