Airbox modifications ?
- Thread starter OB_speed
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OB_emattson
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I understand it to be exactly as you stated.
Nailz
Nailz
G
Guest
You are right Hayabuser, the flap is closed at 2500 rpm or less.
G
Guest
You are right Hayabuser, the flap is closed at 2500 rpm or less.
OB_hayabusa
Registered
The flap acts very similar to vacuum secondaries on a quadrajet carby. At low rpm the flap stays closed giving good throttle response down low. At higher rpm's the flap opens, allowing the engine to utilise the ram-air.
I think!!!, someone may correct me.
I think!!!, someone may correct me.
Okay I agree that removeing the flap and widening the hole would increase airflow. Which I may try to remove the flap next week.
However I am conserned with removing the airbox top or bottom. Wouldnt this effectively eliminate the ramair. I mean with the ram-air effect it would pressurize the box, and if it was open it would now longer be pressurized and thus eliminating all benifits from the ram air.
I agree that opening the channel up would help increase airflow. but I dont know if cut'n the box open will help. I will have to think about this one.
However I am conserned with removing the airbox top or bottom. Wouldnt this effectively eliminate the ramair. I mean with the ram-air effect it would pressurize the box, and if it was open it would now longer be pressurized and thus eliminating all benifits from the ram air.
I agree that opening the channel up would help increase airflow. but I dont know if cut'n the box open will help. I will have to think about this one.
G
Guest
I don't know a lot about the Hayabusa, but owning a Suzuki TL1000R it seems that a lot of the development work of the fuel injection etc was done on the TLR.
What most of us do is remove the flapper valves from the airbox and enlarge the openings, makes the ram air work much better and around 5hp gain across the board.
Alternatively, on the TLR you can just remove the airbox lid altogether, and plug the vacuum lines. This increases the airflow by a huge amount, and increases the "size" of the airbox to the entire under-tank cavity. Some guys lift the tank front 7mm or so as like the ram air it pumps fresh air into the airbox "cavity". Lid off gains about 7hp through all serious revs, but it may run a bit jerky under 3500rpm... And it will make more noise.
Well worth experimenting with, the flappers do nothing above 3000(or so)rpm but get in the way, even when they are full open they still restrict flow.
Hope this was some help!
What most of us do is remove the flapper valves from the airbox and enlarge the openings, makes the ram air work much better and around 5hp gain across the board.
Alternatively, on the TLR you can just remove the airbox lid altogether, and plug the vacuum lines. This increases the airflow by a huge amount, and increases the "size" of the airbox to the entire under-tank cavity. Some guys lift the tank front 7mm or so as like the ram air it pumps fresh air into the airbox "cavity". Lid off gains about 7hp through all serious revs, but it may run a bit jerky under 3500rpm... And it will make more noise.
Well worth experimenting with, the flappers do nothing above 3000(or so)rpm but get in the way, even when they are full open they still restrict flow.
Hope this was some help!
Yes speed I agree this would eliminate the ram air. If you cut the bottom out you will also allow hot air from the engine to come into the air box (BAD.) I agree that removing the the flap may help at high RPM and high speed, but what will that do to our nice smooth HP curve? Will the bottom end HP suffer at the expence of top end? I have not taken the air box appart, but if the flap can not be replaced, I will not remove it untill I see some dyno data with it removed. Why would Suzuki put it there, if all it did is cut HP? Emmisions? HP managability? If i see good imperical data, I will remove it stat.
I get a good KN filter will help some also.
I get a good KN filter will help some also.
OB_outcast
Registered
Does anyone know the procedures for modifying the air box?
what are the new map settings?
what about removing the airbox all together?
what are the new map settings?
what about removing the airbox all together?
G
Guest
I have corresponded with a lot of TLR guys who have removed the lid and/or opened up the airbox on the TLR.
On the 'busa, the airbox is upside down to what we have, on the TLR you can take the lid off and just have the air filter bolted above the v-twin throttle bodies.
BUT, I do know something about the effect of opening up the ram air system, and I have seen many dyno charts of our bikes with the lid off or modified.
The TLR loses about 3 to 5 hp at revs under 4000 (where our flappers open) but GAINS about 7 to 9 hp through midrange to up top, where it matters. On the TLR it is a tried and proven mod, and the dynos show that removing the lid or modifying the airbox give more gains than a full exhaust system - obviously most of us do both - good to have an R1 spanker...
Remember that Suzuki designed our TLRs to kill the superbike opposition, and the 'busa to have the nastiest engine EVER, but then had to "tame" them to the point where Joe Blow could ride around town (as his first bike?? ha ha!) - you get the point. That is why we get stuck with flapper valves, you don't think they are on any TLR/Busa race bikes do you??
Since the 'busa flappers open at 2500rpm you would only expect any losses below this figure, above 2500rpm only good things should happen from opening up the air flow...
The ram air theory has been kicked around the TLR sites for about a year, and what is generally accepted is that ram air does not need to be a perfect system. There are very noticable gains from having the increased flow of a modified intake system, and don't forget that many bikes have a non sealed airbox system like the RGV250.
As long as you pump lots of air into the system it will have greater then atmospheric pressure available at the throttle bodies. That is what counts. The turbulence from the convoluted path that the air must follow from the intakes can reduce the ram air effectiveness, and there are a couple of aftermarket air intake systems for the TLR that have better more curved passages, and we all remove the flappers and that crap plastic that gets in the way of air getting into our motors.
I predict that within a few months this site will be filled with stories of airbox mods and dyno charts showing easy 10+ hp gains from just cutting some plastic... Sorry about the long post guys.
On the 'busa, the airbox is upside down to what we have, on the TLR you can take the lid off and just have the air filter bolted above the v-twin throttle bodies.
BUT, I do know something about the effect of opening up the ram air system, and I have seen many dyno charts of our bikes with the lid off or modified.
The TLR loses about 3 to 5 hp at revs under 4000 (where our flappers open) but GAINS about 7 to 9 hp through midrange to up top, where it matters. On the TLR it is a tried and proven mod, and the dynos show that removing the lid or modifying the airbox give more gains than a full exhaust system - obviously most of us do both - good to have an R1 spanker...
Remember that Suzuki designed our TLRs to kill the superbike opposition, and the 'busa to have the nastiest engine EVER, but then had to "tame" them to the point where Joe Blow could ride around town (as his first bike?? ha ha!) - you get the point. That is why we get stuck with flapper valves, you don't think they are on any TLR/Busa race bikes do you??
Since the 'busa flappers open at 2500rpm you would only expect any losses below this figure, above 2500rpm only good things should happen from opening up the air flow...
The ram air theory has been kicked around the TLR sites for about a year, and what is generally accepted is that ram air does not need to be a perfect system. There are very noticable gains from having the increased flow of a modified intake system, and don't forget that many bikes have a non sealed airbox system like the RGV250.
As long as you pump lots of air into the system it will have greater then atmospheric pressure available at the throttle bodies. That is what counts. The turbulence from the convoluted path that the air must follow from the intakes can reduce the ram air effectiveness, and there are a couple of aftermarket air intake systems for the TLR that have better more curved passages, and we all remove the flappers and that crap plastic that gets in the way of air getting into our motors.
I predict that within a few months this site will be filled with stories of airbox mods and dyno charts showing easy 10+ hp gains from just cutting some plastic... Sorry about the long post guys.
OB_hayabusa
Registered
Don't even think about running the bike with no airbox. All you need is a little stone to go down a throttle body at 10000rpm and you will see why.
The TLR airbox is different to ours so do not attempt the same modifications.
If you wish to remove the flap it is quite simple.
- Remove the airbox from the bike
- Remove the three rubber hoses connected to the bike. The small one that connects to the middle of the bottom is the vaccuum line that opens the flap. Tie this line off and block it.
- Remove the air filter
- The vaccuum mechanism that opens the flap simply twists out of the airbox. Remove this.
- Look inside the box at the flap and you can see how it is attached. The two platic tubes holding the flap in place bend out of the way to unhook the flap.
- Remove the flap out from the air filter hole. This is tricky because it looks as though it won't fit but you can bend the flap slightly and get it out sideways.
- Make up a piece of thin aluminium or similar to block the hole where the vaccuum mechanism was located.
These modifications are fully reversible.
You will notice the bike is more sluggish down low but pulls harder at high revs. However I have not confirmed this on a dyno.
I have made this modification to my Busa and everything runs fine.
The TLR airbox is different to ours so do not attempt the same modifications.
If you wish to remove the flap it is quite simple.
- Remove the airbox from the bike
- Remove the three rubber hoses connected to the bike. The small one that connects to the middle of the bottom is the vaccuum line that opens the flap. Tie this line off and block it.
- Remove the air filter
- The vaccuum mechanism that opens the flap simply twists out of the airbox. Remove this.
- Look inside the box at the flap and you can see how it is attached. The two platic tubes holding the flap in place bend out of the way to unhook the flap.
- Remove the flap out from the air filter hole. This is tricky because it looks as though it won't fit but you can bend the flap slightly and get it out sideways.
- Make up a piece of thin aluminium or similar to block the hole where the vaccuum mechanism was located.
These modifications are fully reversible.
You will notice the bike is more sluggish down low but pulls harder at high revs. However I have not confirmed this on a dyno.
I have made this modification to my Busa and everything runs fine.
OB_hayabusa
Registered
If you wish to cut the airbox, cut at the base of the inside of the filter (allowing the filter to seal). This opens up the area considerably still maintaining all ram air effect. This procedure is obviously not reversible and may have warranty drawbacks.
Thanks, mine will be coming off this week. I might even drag out the dremel and wack open the area under the filter.
I assume that if I could cut the hole bigger and somehow attach a flat airfilter over the hole it would allow more air to flow. Oh my brain is working now ...
My old escort had a 8x12 flat filter. Think of the air i could get through that
I assume that if I could cut the hole bigger and somehow attach a flat airfilter over the hole it would allow more air to flow. Oh my brain is working now ...
My old escort had a 8x12 flat filter. Think of the air i could get through that
Okay I did it. For better or worse I did it.
very noticable lag of throttle response of of 1000-2000 rpms
between 2000-3000 it seems to pull steadily but relatively slowly compared to the 3000 on up.
but after 3000 it pulls veryrapidly with a very distinct rumble. It seems to have a very throaty rumble from the airbox around 3000-4000 rpms
The bike seems to wind up faster, I dont think it just me. The bike seem to rev freely and faster. I assume the opened up area has help the air flow through my busa.
I will dyno it before and after my yosh pipe when it comes it to see what i have lost/gained by this modification.
very noticable lag of throttle response of of 1000-2000 rpms
between 2000-3000 it seems to pull steadily but relatively slowly compared to the 3000 on up.
but after 3000 it pulls veryrapidly with a very distinct rumble. It seems to have a very throaty rumble from the airbox around 3000-4000 rpms
The bike seems to wind up faster, I dont think it just me. The bike seem to rev freely and faster. I assume the opened up area has help the air flow through my busa.
I will dyno it before and after my yosh pipe when it comes it to see what i have lost/gained by this modification.
OB_outcast
Registered
Thanks for the advice ..
Is there anything in particular to do with the other two black hoses?
What about that ten horsepower gain?
Is there anything in particular to do with the other two black hoses?
What about that ten horsepower gain?
OB_Greg Gillis
Registered
I did the airbox mod. My bike dynoed at 148 hp (exactly the same as 2 other Hayabusas)before the mod and 150 hp after. Nothing else was done. It now seems to have a flat spot so I'll probably have to get the injection remapped and hope that fixes it. I wouldn't bother if I knew this is what would happen.
Thanks for the tip hayabusa. My exhaust should be here in a week or so.
Ah thats the words I was loooking for earlier. It does seem to have a flat spot between 2000-3000 rpm. I can live with it. I only see it when I am cruising at low rpms. but even on conservative driving i have it above 3000 on my highway cruising
Ah thats the words I was loooking for earlier. It does seem to have a flat spot between 2000-3000 rpm. I can live with it. I only see it when I am cruising at low rpms. but even on conservative driving i have it above 3000 on my highway cruising
OB_hayabusa
Registered
Re-attach the large hose that is at the rear of the airbox.
The other large hose at the right rear is an emission control system that feeds fresh air from the airbox into each of the four exhaust outlets to ensure a complete combustion - ie. CO to CO2. You can block off this exit and remove the emission hose and the 4 way box and pipes to the exhaust outlets. You must then make up small aluminium block off plates to place over the holes at the exhaust outlets.
This has a negligable effect on performance, may save a few pounds and enrage the greenies.
This modification is reversible. I have performed this mod on my Busa and everything is running fine.
The other large hose at the right rear is an emission control system that feeds fresh air from the airbox into each of the four exhaust outlets to ensure a complete combustion - ie. CO to CO2. You can block off this exit and remove the emission hose and the 4 way box and pipes to the exhaust outlets. You must then make up small aluminium block off plates to place over the holes at the exhaust outlets.
This has a negligable effect on performance, may save a few pounds and enrage the greenies.
This modification is reversible. I have performed this mod on my Busa and everything is running fine.
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