Mild airbox mod

[abraxas]

My 2c ....

The most efficient air to fuel ratio is 14:1. This is primarily for "cleanliness" of exhaust gas, but also relates to performance.

The 02, or lambda sensor, measures the FREE oxygen in the exhaust gas. This then feeds back to the cpu to increase/decrease fuel (to keep the ratio).

Opening the box WILL allow better airflow, but not necessarily improve performance. The lambda sensor will adjust to ensure that no harm is done.

In the pre-06 models (like mine) there is no sensor to auto correct, as such the ratio would be incorrect, without a pcIII remap. The bike would run lean, causing a hotter combustion cycle, wearing the parts over time (not something your buttdyno would tell you).

The airbox is a very specific design, taking airflow, air temp, and noise into account. The whole aim of the airbox (IMHO) is to maintain as steady an environment as possible.
Eanyone notice how much warmer the air intake temperature is, over "normal" ouside? So the first thing that you'll do is cool the intake temp, and hence increase the volume of air.

PS, if the lambda sensor gets dirty, it will not read the oxygen levels correctly, and compensate by adding fuel, to the point of choking the engine.

 

[Doorag]

Wow now thats ann interesting read from start to finnish, would like to see how this ends, only had my FZ6 S2 a week so i wont be modding for a while.

Yeah, that's what I thought as well.

 

[aussiejules]

Yes the optimum a/f is 14:1 but emission control is not. THe o2 sensor is not for optimum performance but for optimum emission controll. Here co2 use to have to be 1.5% but optimum operating performace was 2.5%, the 2.5% was 14:1. what increases fuel mixture is airflow meter, and we all have that in our bikes in the form of a map (manifold absolute pressure sensor). The opening just makes it easier for the engine to get air.

 

[urbanj]

14.7:1 is chemically optimal for a complete burn of the gasoline but that is not the case for peak power which you want it richer. Turbo vehicles can see as rich as 11:1 or lower and most higher performing N/A motors will be in the 13:1 area. 14.7 is pretty lean and hot which can lead to preigniton and detonation. Plus you want to make sure every oxygen molecule is being burned. Also the richer mixture aids in combustion chamber cooling.

The o2 sensor only operates in closed loop which is at cruising and light loads to provide the cleanest emissions. At WOT and higher loads the computer uses the MAP and fuel table to determine the fueling.

 

[Nelly]

Anyone? No comments?

Hi David,

Its all beyond me. I know that when I was running two strokes if I over did the air flow MODS my bikes ran leaner than Kate Moss and burnt holes in the pistons.##
I can totally see Aussie Jules logic but also understand David's argument to.
I have a K&N filter. Its has made no difference in performance, nice induction noise. I got It as it has a life time guarantee.
Also I am very happy with my bikes performance so don't really have the inclination to change something for a couple of ponies that I can't use on the road.

Nelly

 

[Nelly]

We are not forcing the air into the engine via rams, so the speed you`re going doesn`t determine the amount of air that's coming in, it`s the design of the airbox that does. Thus, we don`t need a sensor for airflow. Where in the manual did you (aussiejules) see we do?

Opening up the airbox may make the air more readily available to the engine, and may improve performance indeed. But how do we know where the limit is? How big should the hole be for maximum performance? should we just all add a huge ram to the front of our bikes and it`ll give us 20 more HP??? More air does not automatically means more performance...


Again, my point is that we just don`t know, and until someone gets a proper dyno done, we won`t know for sure.

My personal bet is that gutting your airbox wide open will have a negative impact on performance, and that those who did a mild modification are more likely to see minor improvements (certainly nothing that a butt dyno could detect).

I had a Stan Stephens tune on a two stroke years ago. I ran it with a K&N filter an I was left with a huge mid-range bogged down hole between 3-5K.
So more air in my book won't mean better performance. So I see th validity of Aussies argument. The engine is compensating some how?
Incidental has anyone dropped the plugs out after the mod to see if its running lean or not.

Nelly

 

[aussiejules]

No dont want to go looking too hard, i might prove myself wrong, and i dont want that. (A mechanic that hasnt got a clue, that would hurt my ego)

 

[FZ1inNH]

I don't recall but has anyone ever claimed an HP increase from this? I'd find that hard to believe but I personally think the throttle response is quicker throughout the entire band. I'm pretty sure there hasn't been any changes in HP with this mod but I have stated this previously.

Not bad for drunk posting....

 

[pchbreeze]

When I reached 20k miles on my bike, I started riding it hard. for what its worth, my butt dyno comes from having removed it and put it back repeatedly...back to back. i gained mid and low end adn lost top end.

somewhat agree that the air is going to be a bit too lean at certain rpm's but considering these bikes rev to 16k, that shouldn't be as significant as other factors.

For regular riding, you'll gain a great sound with no consequence. if you're primarily a canyon carver, you have the wrong bike to begin with. for daily riding, this mod has no negative consequence. for high performance engines (includings the fz6's twin, r6) they come with ram air.

 

[pchbreeze]

keep in mind that most people who criticize this mod never want to do it, let alone have done it. most people who have, like it.

I don't recall but has anyone ever claimed an HP increase from this? I'd find that hard to believe but I personally think the throttle response is quicker throughout the entire band. I'm pretty sure there hasn't been any changes in HP with this mod but I have stated this previously.

Not bad for drunk posting....

the throttle response was significant on my bike but i never understood why it had that noticable an effect.

 

[Nick]

When I reached 20k miles on my bike, I started riding it hard. for what its worth, my butt dyno comes from having removed it and put it back repeatedly...back to back. i gained mid and low end adn lost top end.

somewhat agree that the air is going to be a bit too lean at certain rpm's but considering these bikes rev to 16k, that shouldn't be as significant as other factors.

For regular riding, you'll gain a great sound with no consequence. (if you're primarily a canyon carver , you have the wrong bike to begin with.) for daily riding, this mod has no negative consequence. for high performance engines (includings the fz6's twin, r6) they come with ram air.

I bought the wrong bike for canyon carving?hmmm

this is a great read lots of good info. I sure would love to see a dyno comparo!

Cheers

 

[Guitar Man]

Incidental has anyone dropped the plugs out after the mod to see if its running lean or not.

I've had my mod for a little while and have checked the plugs a couple of times since and they look just as normal as they did before the mod.

 

[jocco]

Hi all. I just did the mod I did not saw any difference. Neither in performance nor in sound. At least on low rpm, and that's what I was going for. I'm a bit disappointed, I was hoping the bike would be much louder. I don't think that this insignificant mod can somehow damage the engine.

 

[TeamGreen]

Thanks guys... another mod for us cycle geeks. Where is my wrench and dremel...

 

[fazil]

I think of trying this mod next week.
Are you happy with your enlarged airfilter ?
Any more feedback available?

 

[SANGER_A2]

I think of trying this mod next week.
Are you happy with your enlarged airfilter ?
Any more feedback available?

Read the thread and the many others on the site. Just search for airbox mod. Most like it, some hate it. I did quite a hardcore mod on mine and I LOVE the new sound. It seems better from the off too. There are details on my site in my signature link below. What I love most is when I'm in 6th gear at a really low speed and suddenly got WOT. You get an amazing noise out of the beast!

 

[Wavex]

Thank you very much :Flip:

 

[Wolfman]

Thank you very much :Flip:

Si if this article is to be taken as the gospel, then in reality, if you do the airbox mod, and have a power commander, then all you have to do reap any benefit, or fix the associated loss of power by damaging the airflow with this mod, is to go get a dynotune? yes or no?

Cause that is all the manufacturer is doing when they tune the engine...mapping it to maxiumise the performance as per air flow that is coming in.

:thumbup: