Induction Tuning?

I`m tying a few different things, and will post back when played a bit more.

Goal is to go against the grain of removing an airbox, or lid to achieve the same thing through velocity enhancement.

Why am I doing this?

I was visiting the lad that built my engine about 6weeks ago, and I proceeded to say that I was going to go a stage 2 set up. That being removing the airbox lid, and have the filter exposed.. so he said, why do you want to do that?  I said, there`s a world wide audience that says people have had great success in stage 1-3 set ups. So he said again, why do you want to do that for?  I ask, where are you going with this?
He made the comment that a standard engine, or slightly modified as yours is, won`t gain any more benefit than a properly set up airbox.
He agreed the standard snorkel in place, does restrict air flow, but unless you`ve got a highly modified engine, the engine won`t gain from a stage 2-3 set up.

After looking at holeshot dyno print outs, it seems the most gains happen from a stage 1, and when you do 2-3, your not gaining that much more HP, in carbie form anyway.
So he takes me to his flow bench, and calibrates it to a 2" hole, which is what the existing hole is in my airbox lid with the snorkel removed, and puts a small velocity stack on top. The airflow increased dramatically. He then made a ring from plasticine, and put it around the hole, once again, there was a great increase in flow, to which he replied, air doesn`t like sharp edges, and creates to much turbulence, which restricts airflow. 
So he said have a play yourself, and see what happens.
I have done so, with both set up per photos.  The first photo is of a velocity rubber from internal of the airbox, which I have a spare to play with. The rubber sits in half way from what you see in the photo, as that is its full length...this alone gave me a massive flatspot in midrange, which proves its providing a lot more airflow, to which it would need a major needle and jet tinker to correct.
The second photo is of all things, a curtain ring, which in shape , is essentially a small velocity stack. again its taking away sharp edges, and allowing better airflow.. the result again gave me a small flatspot, in which the carb would have to be played with to correct airflow.
The whole time of these trials, I kept with a standard 50mm ID of everything I`ve tried at the airbox.

So...why are people removing airboxes and lids when the engine doesn`t need it, and maybe in fact, an inferior thing to do?

It's not all about power. Adding headers and exhaust adds a little more horsepower, but its the weight savings that give you a better power to weight ratio.

I'd try ram airing the air box if I was doing what you are trying to achieve. My bike has plenty of bottom end but top end goes away quickly whereas ram air bikes keep on going

reddog wrote:It's not all about power. Adding headers and exhaust adds a little more horsepower, but its the weight savings that give you a better power to weight ratio.

I'd try ram airing the air box if I was doing what you are trying to achieve. My bike has plenty of bottom end but top end goes away quickly whereas ram air bikes keep on going

 That's not what I`m trying to achieve.

Its about efficiency. People are thinking their going to get better airflow by removing airboxes or lids, when possibly, the same thing can be achieved through alternate methods, and maybe even better airflow, and ride ability, through a better set up airbox .

If I was going to go pods, I`d be going for flatslides, and get ride of the CV carbs all together. From what I understand through a lot of reading, the standard carbs will only ever be good for about 135-140HP, If I went flatslide on my set up now, I would have no doubt, I could get close to 150, but I want some sort of economy. So if you want HP, you`d ditch and go a pro set up.
As for injection, I`m sure the standard set up would be limited as well, and the same scenario would apply for big HP

mtbeerwah wrote:Why am I doing this?

I was visiting the lad that built my engine about 6weeks ago, and I proceeded to say that I was going to go a stage 2 set up. That being removing the airbox lid, and have the filter exposed.. so he said, why do you want to do that?  I said, there`s a world wide audience that says people have had great success in stage 1-3 set ups. So he said again, why do you want to do that for?  I ask, where are you going with this?
He made the comment that a standard engine, or slightly modified as yours is, won`t gain any more benefit than a properly set up airbox.
He agreed the standard snorkel in place, does restrict air flow, but unless you`ve got a highly modified engine, the engine won`t gain from a stage 2-3 set up.

After looking at holeshot dyno print outs, it seems the most gains happen from a stage 1, and when you do 2-3, your not gaining that much more HP, in carbie form anyway.
So he takes me to his flow bench, and calibrates it to a 2" hole, which is what the existing hole is in my airbox lid with the snorkel removed, and puts a small velocity stack on top. The airflow increased dramatically. He then made a ring from plasticine, and put it around the hole, once again, there was a great increase in flow, to which he replied, air doesn`t like sharp edges, and creates to much turbulence, which restricts airflow. 
So he said have a play yourself, and see what happens.
I have done so, with both set up per photos.  The first photo is of a velocity rubber from internal of the airbox, which I have a spare to play with. The rubber sits in half way from what you see in the photo, as that is its full length...this alone gave me a massive flatspot in midrange, which proves its providing a lot more airflow, to which it would need a major needle and jet tinker to correct.
The second photo is of all things, a curtain ring, which in shape , is essentially a small velocity stack. again its taking away sharp edges, and allowing better airflow.. the result again gave me a small flatspot, in which the carb would have to be played with to correct airflow.
The whole time of these trials, I kept with a standard 50mm ID of everything I`ve tried at the airbox.

So...why are people removing airboxes and lids when the engine doesn`t need it, and maybe in fact, an inferior thing to do?

the longer the velocity stack you put on the more bottom end it will give and the reverse for a shorter one, but they do work, im with you about removing the lid or whole airbox, might sound fast with the sucking noise but usually not achieving much

Would love to see the engineering behind the design of the orignal airbox and filter.  I have this feeling that they built it more to meet induction noise reduction than any power considerations. For example why did the change the airfilter between the 1200 and 1250 with the later having less area ?  There is certainly a lot more that goes into the final factory design other than what will fit between the frames and makes me wonder that by tampering with one aspect (e.g. holes in lids) are we introducing detremental effects on some other parameter (e.g. more turbulence in the airflow) ?  

Didn't Dale Walker come up with the conclussion it was better to remove the snokle and cut holes in the lid after the many hundreds of dyna-runs he pulled when designing his Stage kits, would be interesting to see if there is actual imperical data on what the difference were.

With a filter in the way I doubt that snorkel will do anything on the outside of the airbox. The newer R1's velocity stacks are adjustable and can change length which is pretty cool.

as I have written, I have already tried this, with both photo examples, and it does make a huge difference with airflow. to the point of hardly running at all with the big rubber stack.

As for the torque being created due to a long stack, that comes into effect, when you have them directly on the carb.
Long for torque, short for higher RPM,

As this is on the airbox, its a different scenario, they are there to correct airflow, and stop turbulence from sharp edges, not so much as speed up the flow, but to continue it at a set rate, that being, what ever your engine will use. The standard snorkel does work, but is to small.

Isnt a hose leading to the airbox from side  or front going to give you more air (ram ). Having a v\stack behind the motor will give you hot stale air ,no?
I would think the faster you go less air available due to the vacuum affect of the motor .I have no idea actually    but the intake hole is in a boxed in place

well I`m no expert on this subject, hence why I`ve chucked all this out there.

If you remove an airbox on a CV carb, which is a vacuum set up, you have to alter things to compensate to make them run, allah stage 3

do you have to remove the airbox to achieve the same thing, when you can possibly fine tune the airbox , ?

I guess when I think more about it, as reddog has touched on, buy putting a stack on the box, it does become a ram, but only through efficiency, not by running an external hose to force more air in from an external force

The fact that airflow increases an the addition of the bell mouth may, imo, be because the hole in question is too small.

This is why (when asked) I do not suggest the stage 1 airbox mod and instead suggest stage 2.

What we are doing is taking the pressure energy in the air, converting some to velocity (kinetic energy which allows us to create flow), and then converting it back to pressure in the cylinder.  If we get it right; then we will minimize our losses and recover all available pressure.  Turbulence in the airflow, and friction within the ducting all result in a reduction in the energy available for recovery.

Short answer:  This shit is rocket science; enter with lots of time, patience and perseverance.

I would think with a stack it could pull air from below its intake . A hole from side and above .Lets buy a $100,000 machine and test it  

From memory we have 4 * 34mm TB's.  OK so if we work out the total area of the 4 venturi's we get 36 sq.cm, or a square hole 6 cm on a side.  So, the sizing of the rubber bell mouth in your pic eyeballs about right.

you said it in one Denkenai..rocket science!!

http://www.formula1-dictionary.net/airbox.html

I still feel, after reading this,( which is still doing my head in ) that a properly designed airbox for our bikes ( that being for correct CMF..Cubic Feet per Minute and disregarding emission laws ) will be better than removing  one.....but, the mathematics involved in this, is beyond my comprehension.

I recon ram air is doable. My brothers zx7 has large air scoops at the front, but both of them reduce down to around 15mm each from memory. 

That little 750 goes hard well above 200kph whereas the Bandit slows down