The most commonly spouted bollex about ram air is that the bigger the scoop, the better the air pressure. Utter shite I'm afraid.

Your bikes' airbox exists as a kind of air reservoir - purely there to provide the engine with cool clean fresh air 'on tap'. Imagine if you didn't have an air box - the air would be rushing over the carbs or throttle bodies at anything up to 200 mp - bloody difficult to get it in the engine when it's in the engine when it's whizzing past at that speed. Hence the airbox holds a near-still supply of pressurised air directily over the carbs to feed them effortlessly with as much air as they need, every time they need it.

The airbox has to be much larger than the capacity of the engine too. If you take the GSX-R1000 as an example: Each cylinder as it fires will need 250cc of air to be sitting there ready to flow into the cylinder, and as the next cylinder fires it will also need another 250cc of air, and so on.

Now, obviously with each 250cc gulp of nice fresh air disappearing from the airbox - there needs to be enough to sustain each of the next 'draws' too, which means that the flow of fresh air into the airbox must be sufficiently high that the rapidly diminishing air can be replenished beforre the pressure drops significantly inside the airbox. Therefore the airbox needs to inflow more than it can outflow - but no more, although even that's a lot of air. Each cylinder uses 250cc , which is 1 litre of air per four revolutions. At 11,500 rpm that's 2,875 litres of air a minute, or 48 litres a second. Going back to the size of the intake and, taking the example of the Gixer Thou again: it has 42mm throttle bodies, which means that the intake needs to be bigger than 42mm to flow more that the cylinder can take - but literally 43mm would do the job, it doesn't need to look like a '50s hot-rod.

The total pressurisation of the airbox is dependant purely on the speed at which the bike is travelling - again, nothing to do with the size of the intaks. Static air has higher pressure that air moving at high speed because air has fixed amount of energy - raise the air speed (kinetic energy) and the pressure energy drops to keep the total volume constant. This is why bikes have airboxes.

In all reality the maximum pressure you're gonna see in the airbox at normal riding speeds is significantly less that 1 psi - so you might be wondering 'why bother?' Well, if you consider that the effect of not having an airbox which even only held the air still would mean that you'd actually be losing power the faster you went - the effect of having positive pressure in the airbox is simply a boost - literally.

Fast Bikes - Apr 03

The most commonly spouted bollex about ram air is that the bigger the scoop, the better the air pressure. Utter shite I'm afraid.

I can't agree with your statement that "ram air" is to boost air pressure. There is no way you could boost air intake pressure unless you are running turbo or supercharging devices. Ram air devices serves the purpose of providing cool air to the engine for combustion. Cool air is more dense than hot air so technically you get more bhp, everything being equal.

The 'Ang Moh' like to remove the airbox and put individual pod air filters when jetted with stage 3 jet kit.

So..... how to achieve this on the dyno cos the bike sitting still?

Even with blowers running i can't see the fans blowing as hard a bike running hard.

then y some guys modify their airbox?
will this way push the performance of the bike?

i took out the snorkel...bikes feels better but louder... :smile:
the louder sound shldnt b a prob wif tp hor? further more i punch mi exhaust liaoz... :sweat:

If replace the orginal with an air filter isit better and can make the bike more powerful. Cause think my bike no air box only an air filter connected to the carb. :confused:

1 thing to clear my doubts. Does it mean that the purpose of the airbox is to hold the air still so that the pressure of the air box is higher then that of the carbs. (air flow for high to low pressure)

1 thing to clear my doubts. Does it mean that the purpose of the airbox is to hold the air still so that the pressure of the air box is higher then that of the carbs. (air flow for high to low pressure)

my humble opinion would be that the air box allows for STABLE and PREDICTABLE air pressures for carb or EFI tuning to work on, for predictable performance. as mentioned in the first post, varying windspeed with an awkward position of the carbs in the bike makes for unstable air pressures that vary at different riding speeds. with or without air box, air will definitely enter the carb body when the engine is running, due to low pressure (vacuum) induced by the engine (piston on intake stroke).

I believe the air box has 2 main functions. 1) to feed air into the throttle body. 2) Regulate air pressure. To combust requires 2 elements, fuel and air. At high rpm, the engine requires more air than the air box can provide thus ram air duct uses the bike's forward momentum to have cool air rammed into the airbox. this creates a higher pressure to cope with the combustion. People taking out the air box will also work provided the scoops are located in such a way that takes advantage of uninteruptted air flowing into the carbs.

Airbox is there to guide & channel filtered air into the throttle bodies. If you notice, most sportbikes capable of going at fast speed have airbox under fuel tank and air intakes at the front. Other than that, air box can be at the side or open without a box construct.

Sometimes we wonder why there isn't a universal airbox design for every bike. We have air vent/tube to channel the incoming air into the air box. Straight, slightly bend at certain angle, single or dual air intakes create diff air pressure at diff speed and all must be taken into considerations together with the bike aero-dynamic design and air-coefficient drag ratio.

The diff types and designs of air intakes create diff air pressure when the bike moves. Often than not, designers have come a long way to build the most efficient airbox, alongside with the change in bike exterior.

Running without air filter is a personal choice as one believes that air-filter induce restriction to air flow. Others argue the fact without air-filter has ill effect on impurities going into combustion chamber. We leave this to individual.....

R&D bike scientists have discovered, other than the fact air temperture changes (although not significantly but in biking technology, mm creates cm, g creates kg) as speed does over a medium, air pressure inside the airbox is NOT LINEAR too! Read up on articles on air on Hurricane and Tornadoes you'll understand more.

Since then, ram air technology is introduced! Read on how Turbo works, ram air borrows the general idea from it into bike air box. Ram air hences regulates air pressure at diff speed when needed to manage better combustion power.

This is how a boost is created when reached a power band. Usually someone likes to removes ram air from their air box as they want to run the bike with move linear power, so to speak!

:P

wow.. i thought air box is to stop dust particle from getting into the funnel onli... newbie x

i remove the airbox from my bike to try and see if there's any difference...my pickup really improves alot...but my top speed ended up reaching only 100km/h...the noise is really cool...but wen it gets high rev...it doesn't have dat "kick" anyomore..so I guai guai put back the airbox...my bike is more predictable wif it...

can anyone tell me where is the air box for s4 vtec1. thamks. :confused:

can anyone tell me where is the air box for s4 vtec1. thamks. :confused:

lift up your tank. There's a black box with 3 screws. Unscrew it and lift off the cap, you will see your air FILTER in that box.

For sp, if take out the airbox leh?
got wad effect other than the sound...
wad are the pro and cons..??

For sp, if take out the airbox leh?
got wad effect other than the sound...
wad are the pro and cons..??
tink bike may run smoother(feels lar) but b prepared 2 hav a dirty carb soon....so better 2 keep it there lor...juz mi 2cents worth... :sweat:
as 4 other efx i nt sure lor...

tink bike may run smoother(feels lar) but b prepared 2 hav a dirty carb soon....so better 2 keep it there lor...juz mi 2cents worth... :sweat:
as 4 other efx i nt sure lor...


oic... :bounce:

hey lao jiaos out there...i yesterday washed mi bike n i took out the filter 2 wash...washed in water then realised i dun hav blower 2 dry it throughly...so bobian i squeeze out as much water as i can then put it bac...izzit ok like dat??? :confused:

hey lao jiaos out there...i yesterday washed mi bike n i took out the filter 2 wash...washed in water then realised i dun hav blower 2 dry it throughly...so bobian i squeeze out as much water as i can then put it bac...izzit ok like dat??? :confused:

Please make sure it's 100% dry. You wouldn't want water in your engine. It is neither combustible nor compressable, the results are not pleasing.

Please make sure it's 100% dry. You wouldn't want water in your engine. It is neither combustible nor compressable, the results are not pleasing.

if i hav been riding since yesterday n (touch wood) everiting seems ok shld b alrite??? :confused:

wah stanboy , you think your original air filter is K&N washable?

better dont try it again.

the effects = choked throttle response

hey lao jiaos out there...i yesterday washed mi bike n i took out the filter 2 wash...washed in water then realised i dun hav blower 2 dry it throughly...so bobian i squeeze out as much water as i can then put it bac...izzit ok like dat??? :confused:

U sure u can wash with WATER?? eeeh, I think yr filter by now should have been torn already! did u oil after u dry?

Just my 5cents thought!

Tony :P :P :P

remove airbox will have faster pick up speed but will not reach the top speed...i test out on a normal motor (just engine with filter kit and carburator) for those big cc one if the air is not enough their engine may overheat easily that why big cc bike need alot of air to cool so they need to have more speed to have more air...correct me if i'm wrong

wah stanboy , you think your original air filter is K&N washable?

better dont try it again.

the effects = choked throttle response

lucki nothin happen ah... :sweat:
went 2 change a new 1 liaoz... :P

U sure u can wash with WATER?? eeeh, I think yr filter by now should have been torn already! did u oil after u dry?

Just my 5cents thought!

Tony :P :P :P

nope...i nv oil @ all...juz dry as much as i can n put bac... :sweat:

wht happen if u didnt fix a airbox in yr bike?for a 2b bike lah :sweat:

wht happen if u didnt fix a airbox in yr bike?for a 2b bike lah :sweat:

loss of acceleration.

but i c quite many krr didnt put air-box leh :sweat:

u try b4?i no for krr w/o air-box morn quite hard to start 1 :sweat:

to other is right that they put back their air-box,for me i cant cause my air-box opening nt big enough :sweat:

My air box no filter one~ is it because its a 2B bike? Wad if i put a cone filter inside the air box?

Where to find aftermarket filters for airbox?

Where to find aftermarket filters for airbox?

****ing nobody answer my qns~ :mad:

****ing nobody answer my qns~ :mad:

if i put cone filter, dat means my air box is not there liaoz mah~ then how to direct air to the air filter? making a big tube towards it? :confused: no air box means air filter easily dirty, and can get wet summore~

hey heres some point that i think is quite interesting that was tested by e ang moh... its pretty long.. but in full details of wat they tested for ram air..

http://www.rrzone.com/929products/ramair/ramair.shtml

http://www.rrzone.com/929products/ramair/r...ramairexp.shtml (http://www.rrzone.com/929products/ramair/ramairexp.shtml)

I newbie in this airbox thing... I heard some people drill holes in their airbox to make it go faster... is this true that drilling holes in the airbox will make the bike go faster?

Removing the air filter will put less restriction to the air intake, so more air can flow easily into the engine. However, this means the air/fuel mixture is leaned out too, therefore the increase in performance (if engine was running rich with air filter) or decrease in performance (if engine is running too lean).

Too lean mixture can result in serious engine damage! Becareful...

Wah lau!

it is essential that you run your bike with the airfilter ON! gawd, have you seen what particulate matter from riding can do to the slide (in the carb) and other parts of the engine??? what a crazy nehnek idea is it that no airfilter=better performance! sure you'll get better performance but at what cost? damage to sensitive components that are hard to get at and expensive to fix! its just not worth it!

if there was no need for an airfilter, the manufacturers would not have put in one. The airbox also serves as a component of the combustion cycle's breathing system. Air box shape and interior volume is designed to improve engine breathing by resonating at specific points in the engine's power band.

anyways, if you want better performance, get a bigger bike lah!

air filter care:

paper filters are meant to be replaced. once they reach the service limit, replace them.

foam filters: wash with mild soad (basically squeeze with soap and water), dry completely, and reoil (oil is an essential component of air filter care- helps trap particles). so it is a good idea to get 2 filters. one on the bike, and one spare. so when you need to change/clean your filter just use the clean one and wash the soiled one before your next change is due.

k&N: make sure you get the recharge kit. meaning spray filter cleaner and filter oil. this is a high flow and easy to maintain system.

all this advice is for your daily rides. now if you are racing, its a different matter cos you'll be looking at engine rebuilds on a regular basis. but how many of us can afford that? take care of your bike and she'll take care of you!

can i ask the mech to wash the k&N filter ???

wad purpose does it serves ???
wads is the difference between the k&N and normal airbox in krr ???

Originally posted by kAtH3rIn3@Apr 29 2004, 06:43 PM
can i ask the mech to wash the k&N filter ???

wad purpose does it serves ???
wads is the difference between the k&N and normal airbox in krr ???
K&N air box??? or are u referin to K&N Air Filter???

the only advantages of K&N air filter is it can be reuseable lor..

KNN is Reusable so that can save $$money$$ when comparing with replacing costly unwashable air filter.

where to buy KNN cone air filter n how much???

if don;t put air filter carb will get dirty. if put filter gt top speed but no pick up. isit like tat????????

what if i put a small fan blowing towards my air filter, will it work?

Originally posted by zinc1@May 2 2005, 10:50 AM
what if i put a small fan blowing towards my air filter, will it work?
sounds like what people call a "supercharger" i think. except supercharger the fan should be more "hardcore". if really manage to put a lot more air into the carb, then need to re-tune carburetor (increase fuel supply) also lor, or else will have "lean" mixture.

don't really know a lot about these things la.. better someone else answer. =)

edit: eh, fan put in front of air filter ah? i think if put after air filter will be more efficient? if put before.. the increase in "windspeed" from fan might just be a fraction of what you'll get by riding normally, then a bit no point (but i really have no idea how much difference it'll make). i think superchargers' air pumping takes place after filtering.

is using airbox better than using air filter

Originally posted by Vpower@May 16 2003, 11:40 AM
Usually someone likes to removes ram air from their air box as they want to run the bike with move linear power, so to speak!

Not true at all! The ZX-7R P model has TWIN ram air ducts and still has the most linear power band testers had known for sportbikes.

is there such a thing called Ram air?Wat's do?:confused:

how come sum airbox the hole is facing the back??

and i have seen some ppl put vacuum hose is that good? coz the vacuum hose like got turbulance...

may i ask ram air and air box are they different? Can add ram air to carb bikes?:smile: Does ram air add more bHp to our bikes?:smile:

my super4 previous owner go drill a hole at the airbox.. will it haf any diff in performance and any side effect?

ps: how much does a new airbox for s4 cost?

Originally posted by Andy ar@Mar 11 2006, 03:06 AM
my super4 previous owner go drill a hole at the airbox.. will it haf any diff in performance and any side effect?

ps: how much does a new airbox for s4 cost?
:help:

i feel like putting K&N air box, and K&N filther...

But i dun noe wat is tat? AIR box is for better speed? and the filther is for preventing dirty particles entering?...i wan my bike 2 sound Hollow...and a bit loud.. is it illegal? and i believe some of us, open stomach? i also not sure but stomach thing...

Pls advise

Originally posted by jeffrey83@Mar 13 2006, 09:18 PM
i feel like putting K&N air box, and K&N filther...

But i dun noe wat is tat? AIR box is for better speed? and the filther is for preventing dirty particles entering?...i wan my bike 2 sound Hollow...and a bit loud.. is it illegal? and i believe some of us, open stomach? i also not sure but stomach thing...

Pls advise
There is no K&N airbox.

An air box is a device to guide air to e carb.
By removing e airbox, u will be running way too lean.
If u want ur bike to sound hollow, u can just poke holes at e side of e airbox.

An air filter is a device which removes undesirables such as dust, pollen, mold, and bacteria from e air entering ur carb.

Its illegal to tong ur exhaust. If caught $70. It is very easy to catch one with tong end can. If there is a small screw at e bottom of e end can, it means e end can is operated b4.
Just tong ur stomach n leave ur end can alone.
It will achieve e same purpose of reducing back pressure but is alot softer n harder to be caught.
Anyway both my stomach n end can is tong.

my air box doubles up as an air filter.

Originally posted by gekokujyou@Mar 13 2006, 09:58 PM
There is no K&N airbox.

An air box is a device to guide air to e carb.
By removing e airbox, u will be running way too lean.
If u want ur bike to sound hollow, u can just poke holes at e side of e airbox.

An air filter is a device which removes undesirables such as dust, pollen, mold, and bacteria from e air entering ur carb.

Its illegal to tong ur exhaust. If caught $70. It is very easy to catch one with tong end can. If there is a small screw at e bottom of e end can, it means e end can is operated b4.
Just tong ur stomach n leave ur end can alone.
It will achieve e same purpose of reducing back pressure but is alot softer n harder to be caught.
Anyway both my stomach n end can is tong.
okie.. so wat shld i tell the bike shop?... if i wan tong? pls advise this NEWBIE! thanks:thumb:

For kr150, if take out the airbox?
the sound will be hollow?
wad are the pro and cons..??

guys i am riding a wave S and i have this racing carb installed by my previous owner... And with this carb i cannot even put in the airbox... Is it a good choice to run without it>? wad's its pros and cons?

For kr150, if take out the airbox?
the sound will be hollow?
wad are the pro and cons..??

do not try to do that. it takes professional and highly skilled engineers to design and built that bike. whatever they did,they were had safety in consideration plus i wonder why we always want to outsmart the genius?

Some history books will state that Pierre and Ernest Michaux, the French father and son team of carriage-makers, invented the first bicycle during the 1860s. Historians now disagree and there is evidence that the bicycle is older than that. However, historians do agree that Ernest Michaux did invent the modern bicycle pedal and cranks in 1861.:thumb:
-------------------------
Shakira Janet

Guaranteed ROI (http://www.drivenwide.com)

It's there so that oil fumes from the engine are directed back into the combustion chambers to be burnt instead of being vented to atmosphere. Years ago the pipe used to just hang down under the car so that clouds of fumes and oil droplets could spray over the car behind you as your engine became worn.
-------------------
Shakira Janet

Guaranteed ROI (http://www.drivenwide.com)

It's there so that oil fumes from the engine are directed back into the combustion chambers to be burnt instead of being vented to atmosphere. Years ago the pipe used to just hang down under the car so that clouds of fumes and oil droplets could spray over the car behind you as your engine became worn.:angry:
-----------------
Shakira Janet

Guaranteed ROI (http://www.drivenwide.com)

so if airbox is taken out we need to service our carb more frequently ?

can anyone pls clear my doubt pls... :(
btw i riding x1r

depends on ur riding technics also...
airbox taken out n air box without filter is the same...
lolx....

wash carb everytime u service lo... lolx..
=)

waa like that dam chor sia i think next servcing i gonna put back my airbox n filter. btw x1r can put better airbox like knn or other branded airbox ?

washing carb is to my sp is like ard 4-5 mths once or everytime u do full servicing juz in case ur bike stall due to dirty carb.. =)

u put back the air box.. u also have to re-tune ur bike...
if not, air / fuel intake ratio is wrong resulting in loss of power & fc

is it good to drill hole on airbox ? power stronger ?
whats the pros and cons ?

Imagine riding with an open face helmet and open your mouth wide. What goes into the mouth is the same stuff that goes into your engine if u remove the air filter / drilling holes at the airbox. Would any guys like the idea of those stuff going into your mouth???

those dirty stuff all these.. icic.. kinda get it. but why so many ppl stil drill hole if its not good ?

washing carb is to my sp is like ard 4-5 mths once or everytime u do full servicing juz in case ur bike stall due to dirty carb.. =)

u put back the air box.. u also have to re-tune ur bike...
if not, air / fuel intake ratio is wrong resulting in loss of power & fc

u can wash ur carb hw long interval as u wan.. it's all up to u on hw u wanna keep ur carb clean.. some dont even bother to service it.. some 2-3mths.. some 3-4, some like you 4-5.. for me every mth is the best.. if not at least 2mths once..

fyi:
- bike won't stall due to dirty carb.. unless ur carb suck in some stuffs like leaves or what that choke the carb itself that air cant go in n it cant start..
- take out/put back airbox need to balance back the air fuel ratio back..

if u take out ur airbox, more air less petrol = running lean( lean = nt enuff petrol)
if ur previous setting swee swee.. then u hand itchy.. put back airbox.. now is less air more petrol = running rich(too much petrol)

normally for good pickup u can mess with the airbox.. alternatively.. use back airbox with high-flow air filter is good..
y i say for pickup.. u see those race bikes(eg kups, etc).. all running mostly w/o airbox.. cos their setting is pickup base.. not the midrange-topspeed range..


those dirty stuff all these.. icic.. kinda get it. but why so many ppl stil drill hole if its not good ?

cos it provides higher air intake, the alternative purchasing a high-flow air filter is by drilling holes.. depending on the rider requirement.. some setting(aka tuning) they need more air intake to compensate for the high fuel supply.. therefore with stock airfilter w/o holes insufficient air supply.. so they either drill holes.. or they take out filter.. or can put a high-flow air filter like k&n, bmc.. etc


for 2strokers if u running ur bike w/o air filter, best is u remove ur carb and wash it maximum 2mths intervals.. for me i do it monthly.. 2strokes bikes need more care than 4strokes...

thx alot~ thats a really helpful post.. i learned something.. :lovestruck:

It's all up to individual preferences. If you want long service life, leave everything on. If you wanna mess with it, why worry?

And there's so much misconception going on around here... Some bike you take out airbox, it wont even idle properly. Some bikes it doesnt care if it has an airbox (performance wise). Mostly due to factory carburettor settings and design/position of the components.

Meaning some bikes you remove the airbox will affect the setting tremendously while others dont.



To the filter or not part, it's either filter, hi-flow filter or no filter. First two no need to say.

As for the no filter, many races bike dont use them and can perform well but requires to be service regularly. If you scared, dont go this route. If you go this route, dont complain. I ever had a small speck of sand stuck in one of my valves and cant start. But i just bring it to be torn apart to remove it, no biggie.

Anyway it's you ride the bike not the engineers. So depends on you intent to get out of the bike lor...

ok guys, I think you can not generalize the purpose of an airbox ;-)

every engine will run without an airbox but does it run better? I would give it a clear NO....

you can take every modern bike it will only run properly with an airbox, on the other hand almost every bike (at least in Europe and the USA) is restricted through the airbox/intake runners and exhaust system.

Ducati was the 1st manufacturer using the advantage of an airbox and they done pretty well if I remember correct.......

so don't compare a rattling 10year old super four with a R1 or similar and I don't think most of you guys are able to feel the difference anyways (no offense just a general statement)

if you wanna do some reading why modern race bikes need an airbox:

http://en.wikipedia.org/wiki/Helmholtz_resonator

cheers

mjv

gt smth to ask
my dad kup kia abit siao siao
once i slow down den stop at junction
the engine will die off even though i'm at neutral gear
izzi the airbox smth wrong or the air filter too dirty liao???

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deleted post.

great info!

any idea how much worse will fc be fixing open pod filter on a two stroke?