My Version of the Airbox Mod to my '08

[SANGER_A2]

There's been quite a bit of discussion about the airbox mod, how to do it and the effects on the forum recently. so I thought I'd try it and document what I did.

Some people say that it eliminates a high pitched whine and improves the performance and through-flow. Some people say that it screws up their idle speed.

The first step is to get the cover/lid off the airbox - do NOT try to mod it on the bike. You'll either damage the bike or get crap in the engine. This is easy and takes about 5 minutes. On the faired Fazer, you need to remove the four allen bolts on the side of the bike in order to take out the two small bits of inner fairing that hide the gap next to the tank. Then undo the two bolts at the front of the tank holding it into place. Then remove the seat and lift up the tank. I was lazy and just rested it on a bit of rag on the handlebar. You need to unscrew the 6 philips screws holding the top of the airbox on and you can remove it and start cutting!

Here you can see the top of the airbox cover as stock. The hole points towards the front of the bike next to the battery:-


Here you can see the underside of the airbox cover:-


Here you can see the inside of the airbox cover:-


Here is my Dremel that I used to chop bits out. You could probably use a hacksaw but it would take much longer and be much more effort:-


I chopped off the spout thingy on the outside of the cover and also both sides of it that were on the inside:-


Here's a closeup after I smoothed off the edges a bit with a knife:-


Here you can see the inside. There's a lot less plastic there now:-


I left about a cm of the spout in there as I didn't fancy the air blowing straight onto the air filter:-



Nearly done now...

 

[SANGER_A2]

VERY IMPORTANT!!! BEFORE REINSTALLING, I CLEANED THE COVER! There were loads of bits of plastic all over it and I cleaned them all off and dried it. I didn't want any of that rubbish going into the engine or blocking anything (including the filter).
I put the lid back on the airbox and went for a ride. I couldn't really tell much difference. It did sound a bit less whiny but not a huge amount. The idle was exactly the same as before once warmed up 1000rpm and no wavering. So I took the cover off again and started chopping again...

Basically, I removed all of the spout thingy from the inside and out and smoothed off all the edges:-


Here's a nice closeup - there's a much larger gap now:-


And from the inside:-


And from the inside again:-



After cleaning and reinstalling the cover I went for a longer ride. At first I wasn't sure of the difference. Then I realised, I could hear a throaty roar from the engine and the roar from my Scorpions but no annoying whine coming from underneath me! I always thought this was just the noise the engine made and there was nothing I could do about it. It sounds sooo much better now and the mod was free. It's definitely had no negative effects on riding or performance and it may even be a bit better than before.

If you're thinking about doing this mod, don't hesitate any more (well as long as you have an 07+). I don't know if it will work as well with the older bikes as they don't have the O2 sensor in the exhaust. It may work the same. I've tried riding with and without my noise-reducing headphones and it sounds great. The engine whine no longer drowns out the sound of the exhausts. BRILLIANT! :rockon:

 

[SovietRobot]

I'll use these as a guide when I chop my extra airbox lid, thanks!

 

[Rob2222]

Is the bike now louder or is it just another sound? Would be nice to eleminate some of the high-rpm-whine but I didn't want to make the bike (much) louder.

BR Robert

 

[SANGER_A2]

Is the bike now louder or is it just another sound? Would be nice to eleminate some of the high-rpm-whine but I didn't want to make the bike (much) louder.

BR Robert

To my ears it almost seems quieter as it's a deep roar instead of a high pitched whine. Ears hear different pitches differently so the higher probably sounded louded than it was in decibles. I'd guess no louder, just deeper.

 

[Motogiro]

Thank you for a great post! You did a great job on your modification.

I've seen mentioned a number of times in reference to air box mods. and the O2 sensor.

My understanding of the air box mod. is to give the motor the ability to get more air at any given moment. Getting gases into and out of an engine are paramount to performance gains as well as efficiency. So if you change out your exhaust and do an air box mod so the engine breaths better your performance should increase regardless of the O2. There are many variables to consider when we talk about the O2 sensor. How the O2 sensor effects performance can be predicated on design in the system as well as open/close loop conditions.
Here's a link that has a little more info on the subject...http://en.wikipedia.org/wiki/Oxygen_sensor

Again, thank you for a great post and great mod.

 

[Wolfman]

That's pretty much how i did mnine...only difference's i noticed was that there was a raspier induction roar, when revs get above 8000....and a little crisper acceleration....

Nice job, nice write up...i reckon this is a simple, harmless mod, that gives the bike just a little more "personality".

:thumbup:

 

[jtarkany]

I just did mine today. I can't vouch for any performance increase, but the whine is gone, the throttle is more responsive and the sound a little deeper and throatier. I can't wait to add the V.A.L.E. M2 Slip Ons.

 

[Hellgate]

Great documentation, well done. :thumbup:

 

[SovietRobot]

I bought an extra airbox cover and cut it exactly the same way as this.

I installed it yesterday(and resynced my throttlebodies, even though it probably didn't need it) and took it for a ride.

First thing I noticed, it's LOUD! but only under full throttle acceleration. It doesn't sound any different at idle or highway cruising.

I did notice that throttle response is a little quicker and crisper, and low-medium range acceleration feels like it's improved. Before if I went full throttle in 2nd gear at 4,000RPM it would bog down and take a little bit to start to move, but now it feels quicker.

I've heard comments about it making peoples bikes "run like crap" and "can't go over 10kRPM" and that's all BS.
It runs all the way up to redline QUICKLY, and SMOOTHLY.

My only real complain is how it vibrates and how you can hear the air going in under full throttle, but other than that it's a neat easy mod.

 

[Boneman]

I'm adding this mod to my "next mod to do" list!

Great wrtie up and pics! Thank you! :cheer:

 

[hank]

i did this mod over the weekend and it was definitely worth the time to do... no real power gain but it does sound a little meaner, lol it goes good with my scorpions:rockon:

 

[Tom]

I did mine today and took for a little spin and reckon its its pretty awesome!

 

[ross_mct]

I'm very keen to do this mod to my '04 FZ6, but have a couple of questions or rather worries:

1) What does this mod do to the F/A mixture ratio, and does the engine management system compensate for the increased air?

2) Does it affect the fuel effeciency at all?

3) Are there any mechanical downsides to this mod?

Sorry for the silly questions, just read to many of these threads and i've been totally confused by it all.. Thanks a great forum guys!

 

[SANGER_A2]

I'm very keen to do this mod to my '04 FZ6, but have a couple of questions or rather worries:

1) What does this mod do to the F/A mixture ratio, and does the engine management system compensate for the increased air?

Not a lot, may be a bit leaner, but the answer is "yes" to the second part of the question.

2) Does it affect the fuel effeciency at all?

Probably a bit as more air and fuel can go through, but of course you will need to rev the bike less to get the same speed/acceleration so it should balance out.

3) Are there any mechanical downsides to this mod?

Nope. The injection system handles it for ya!


EDIT: I've realised my answers were kinda vague there so some informed people chipping in with details will probably help!

 

[aj_fz6]

Would it be worth my time to do this even though I have the stock exhaust?

 

[Wavex]

Not a lot, may be a bit leaner, but the answer is "yes" to the second part of the question.

Probably a bit as more air and fuel can go through, but of course you will need to rev the bike less to get the same speed/acceleration so it should balance out.


Nope. The injection system handles it for ya!


EDIT: I've realised my answers were kinda vague there so some informed people chipping in with details will probably help!

Can you tell me how you know that the FZ6 (any year) compensates for the increased air coming in without a MAF sensor? I am interested.

 

[SANGER_A2]

Can you tell me how you know that the FZ6 (any year) compensates for the increased air coming in without a MAF sensor? I am interested.

I'll leave it to someone like Boneman or Wolfie who know a lot more about bikes than me to explain! :cheer:

 

[Wavex]

IMHO, they won't be able to, because the FZ6 has a fixed map that only adjusts to small, pre-determined variations based on temperature (temp sensor in Airbox) and emissions (O2 or lambda sensor for '07+ models)... it CANNOT be used to make adjustments to more volume of air coming in because 1) there is no MAF (mass air flow) sensor, and 2), the map is fixed (with only pre-determined small variations to the fixed map possible).

I am not being an ass here, I just don't understand how so many ppl cut their airbox without really knowing what it's doing to their bike, and then claiming that it's OK because it sounds better. To me, a sudden change in engine sound is not a good sign, and changing the AFR randomly is just not a good idea without having a dyno available to empirically confirm what's going on.

We're not talking about a tractor here, the FZ's engine is a high performance, highly tunes piece of engineering running at 14k+ rpms...

But anyway, I'll go back in my hole now

 

[SovietRobot]

IMHO, they won't be able to, because the FZ6 has a fixed map that only adjusts to small, pre-determined variations based on temperature (temp sensor in Airbox) and emissions (O2 or lambda sensor for '07+ models)... it CANNOT be used to make adjustments to more volume of air coming in because 1) there is no MAF (mass air flow) sensor, and 2), the map is fixed (with only pre-determined small variations to the fixed map possible).

I am not being an ass here, I just don't understand how so many ppl cut their airbox without really knowing what it's doing to their bike, and then claiming that it's OK because it sounds better. To me, a sudden change in engine sound is not a good sign, and changing the AFR randomly is just not a good idea without having a dyno available to empirically confirm what's going on.

We're not talking about a tractor here, the FZ's engine is a high performance, highly tunes piece of engineering running at 14k+ rpms...

But anyway, I'll go back in my hole now

The sound of the engine doesn't change.

The loud noise is from the air going into the airbox, because the stock airbox is designed to be quiet as hell.
It's the same deal on cars, the stock airboxes are made to be quiet, and when you replace them with less restrictive ones, you hear the air.

Honestly I wouldn't suggest this mod on a stock bike, but since I have an excellent PCIII map and whatnot, it did make a performance(even if small) difference for me.