High flow air filter

[adjuster]

I don't have the figures with me at the moment, but the flow rates of the K&N and Stock air filter BOTH exceed the maximum air demand of this engine at peak RPM.
 
Engines are NOTHING but a fancy air pump that burns fuel. Design and fluid dynamic laws can be used to get the best possible flow into and out of the engine, but in the end, it's about displacement and RPM. That determines how much air and fuel you can burn. (Add in forced induction, and that changes, but that's a whole other subject.)
 
So, the max amount of air the CP3 engine can EVER need is exceeded by the flow capabilities of the STOCK filter.
Adding the K&N, or any other filter to this design might slightly change the resistance to air flow over the filter, and if the filter was marginal in size, or flow it might matter. BUT the stock filter is WAY LARGER in flow than the CP3 engine will need, even at max RPM.
 
What this means is at everyday engine speeds, the flow across the stock filter is allowing all the air the engine can use all the time. Even up to peak/max RPM it's still allowing more air by a large margin than the engine will ever use, so there is ZERO gain to be had from a "high" flow media or even larger pleat surface area.
 
Sorry K&N and the rest, this engine really does not get anything out of a replacement filter.
 
IF you want to do the math for yourself, just plug in the bore size, stroke and max rpm. (Or Displacement and RPM) into any normally aspirated factor. (The figure changes if you supercharge, turbo charge or otherwise force air into the engine as "boost.")
 
You will find that the amount of air needed by the CP3 engine is much less than the K&N filter provides, and still far less than the Stock Yamaha air filter provides. So, no gain.
 
Can you get air into the air box to the filter better? Sure. But the stock design is pretty dang good, as noted by others, it's tuned for sound and power, and Yamaha did a great job. Want more sound? Cut off a few inches of the snorkle. Want more air flow? Open up the "dirty" side of the air box.
 
But nothing you do on the air box mod will change the fact that the CP3 engine at full chat/rpm will never flow more air than the stock filter can provide with room to spare. (Thus why there is zero change in dyno results from filter changes/upgrades, and air box mods other than mostly sound, we all ride at lower RPM most of the time, and the stock air box flows plenty of air at that RPM or air demand by the engine.)
 
It's about what sound you want on this bike more than how much power you get.
 
What's funny is the exhaust is very similar. There are a few gains to be had, but often at the loss of low end power on this bike. But again, it's about noise, weight and cool factor in many cases. So mod away.
 
 

[peporter]

There are other threads reporting that removing the foam that is on the bottom of the gas tank improves air flow and gives 3 to 4 extra hp at higher rpms. If that foam is the restrictive factor, maybe a high flo air filter would help more if the foam is removed.

Has anyone entertained the idea that MAYBE the foam on the bottom of the tank is insulation from the engine heat? 

[carey]

There are other threads reporting that removing the foam that is on the bottom of the gas tank improves air flow and gives 3 to 4 extra hp at higher rpms. If that foam is the restrictive factor, maybe a high flo air filter would help more if the foam is removed.

I spoke with a tuner that has done a lot of dyno time with the FZ/FJ09. When I asked him about air filters, he stated that air filters made very little difference.  He even tried removing the air box and running individual filters, and remapping the ECU.  There was no significant difference in power.   

[koth442]

Has anyone entertained the idea that MAYBE the foam on the bottom of the tank is insulation from the engine heat?

I haven't been under the tank yet but I'm almost certain it is.

[peporter]

Has anyone entertained the idea that MAYBE the foam on the bottom of the tank is insulation from the engine heat?

That spot is at the leading edge of the engine and rather exposed to fresh air, so heat soak wouldn't be an issue, especially when in motion... in my opinion that is. I know that seems to be an issue in some cars, where the hood/bonnet can sometimes trap the heat along the air intake snorkel. 
I have mine removed (just the front piece)... and the intake growl is more pronounced than before... me likes .

Yeah, I removed the front piece also, but left the rest in place. I live in Oklahoma, and engine heat is a real concern in the summer. The idea of gas heating up in the tank makes me uneasy.  

[duhs10]

I don't think that front piece of foam is going to make any real difference in how much heat from the engine affects the tank. It's in a place that will see a good volume of air flowing by and it sits on top of the air box, so not directly next to the engine.
 
Also, think about all the air cooled motors that have a metal tank just sitting on top of the frame right above the cylinders.
 
 

[peporter]

I don't think that front piece of foam is going to make any real difference in how much heat from the engine affects the tank. It's in a place that will see a good volume of air flowing by and it sits on top of the air box, so not directly next to the engine. 
Also, think about all the air cooled motors that have a metal tank just sitting on top of the frame right above the cylinders.
 

They usually don't have bodywork keeping the heat close to the tank also.  Agreed  that the front piece is the best place to prune! just my opinion, but leave the rest alone. 

[Cruizin]

I don't think that front piece of foam is going to make any real difference in how much heat from the engine affects the tank. It's in a place that will see a good volume of air flowing by and it sits on top of the air box, so not directly next to the engine. 
Also, think about all the air cooled motors that have a metal tank just sitting on top of the frame right above the cylinders.
 

They usually don't have bodywork keeping the heat close to the tank also.  Agreed  that the front piece is the best place to prune! just my opinion, but leave the rest alone.

 
Nels at @2wheeldynoworks has reported finding almost no significant power increase with these so called "high flow" air filters in his dyno tests.
 
An Airfilter's only job is to keep dirt from entering the engine. The Stock Yamaha filter is designed to work perfectly with the size and flow of the airbox and engine. It also does it's job of keeping dirt out of the engine very very well.
 
I have seen people lose alot of power by monkeying with airfilters and intakes and dirt getting in and scoring their cylinders, losing compression, TQ and HP as a result of trying to find some magic extra 1 hp with some crazy air intake ideas.
 
On my dirtbikes I change my airfilters out after ea ride and totally inspect and clean the airboxes. Streetbikes I totally inspect my airboxes often for dirt, and whenever I get close to the airbox I take the opportunity to just change the Air filter while I'm in there just to be sure that everything is clean.
 
Airfilters are to keep dirt out of an engine. Over the long run, the best thing you can do to keep high hp numbers and performance is to just keep that intake clean, keep dirt out the engine and cylinders.
 
Raceteams who use custom airboxes and filters, remember that they are rebuilding that engine after each race anyways. Are we rebuilding our street engines that often?

[Buggy Nate]

They usually don't have bodywork keeping the heat close to the tank also.  Agreed  that the front piece is the best place to prune! just my opinion, but leave the rest alone.

Nels at @2wheeldynoworks has reported finding almost no significant power increase with these so called "high flow" air filters in his dyno tests.  
An Airfilter's only job is to keep dirt from entering the engine. The Stock Yamaha filter is designed to work perfectly with the size and flow of the airbox and engine. It also does it's job of keeping dirt out of the engine very very well.
 
I have seen people lose alot of power by monkeying with airfilters and intakes and dirt getting in and scoring their cylinders, losing compression, TQ and HP as a result of trying to find some magic extra 1 hp with some crazy air intake ideas.
 
On my dirtbikes I change my airfilters out after ea ride and totally inspect and clean the airboxes. Streetbikes I totally inspect my airboxes often for dirt, and whenever I get close to the airbox I take the opportunity to just change the Air filter while I'm in there just to be sure that everything is clean.
 
Airfilters are to keep dirt out of an engine. Over the long run, the best thing you can do to keep high hp numbers and performance is to just keep that intake clean, keep dirt out the engine and cylinders.
 
Raceteams who use custom airboxes and filters, remember that they are rebuilding that engine after each race anyways. Are we rebuilding our street engines that often?

 
You guys are missing the fact that you only need to buy one filter for the life of the bike rather than multiple stock filters, I have run k&n style filters in the dirt bike too and have seen them entirely caked with mud and dirt and nothing has come through.
Once a foam or paper style filter has got to that stage it has wicked through or diminishing the filters flow rates.
And besides it is better for the environment! ?

[koth442]

Nels at @2wheeldynoworks has reported finding almost no significant power increase with these so called "high flow" air filters in his dyno tests.  
An Airfilter's only job is to keep dirt from entering the engine. The Stock Yamaha filter is designed to work perfectly with the size and flow of the airbox and engine. It also does it's job of keeping dirt out of the engine very very well.
 
I have seen people lose alot of power by monkeying with airfilters and intakes and dirt getting in and scoring their cylinders, losing compression, TQ and HP as a result of trying to find some magic extra 1 hp with some crazy air intake ideas.
 
On my dirtbikes I change my airfilters out after ea ride and totally inspect and clean the airboxes. Streetbikes I totally inspect my airboxes often for dirt, and whenever I get close to the airbox I take the opportunity to just change the Air filter while I'm in there just to be sure that everything is clean.
 
Airfilters are to keep dirt out of an engine. Over the long run, the best thing you can do to keep high hp numbers and performance is to just keep that intake clean, keep dirt out the engine and cylinders.
 
Raceteams who use custom airboxes and filters, remember that they are rebuilding that engine after each race anyways. Are we rebuilding our street engines that often?

This.

[phpaul]

Nels at @2wheeldynoworks has reported finding almost no significant power increase with these so called "high flow" air filters in his dyno tests.  
An Airfilter's only job is to keep dirt from entering the engine. The Stock Yamaha filter is designed to work perfectly with the size and flow of the airbox and engine. It also does it's job of keeping dirt out of the engine very very well.
 
I have seen people lose alot of power by monkeying with airfilters and intakes and dirt getting in and scoring their cylinders, losing compression, TQ and HP as a result of trying to find some magic extra 1 hp with some crazy air intake ideas.
 
On my dirtbikes I change my airfilters out after ea ride and totally inspect and clean the airboxes. Streetbikes I totally inspect my airboxes often for dirt, and whenever I get close to the airbox I take the opportunity to just change the Air filter while I'm in there just to be sure that everything is clean.
 
Airfilters are to keep dirt out of an engine. Over the long run, the best thing you can do to keep high hp numbers and performance is to just keep that intake clean, keep dirt out the engine and cylinders.
 
Raceteams who use custom airboxes and filters, remember that they are rebuilding that engine after each race anyways. Are we rebuilding our street engines that often?

This.

Indeed, This ^^^ Which is precisely why there will never be a K&N filter on anything I own.  More flow=less filtration and you'll never convince me otherwise.

[empire00]

Nels at @2wheeldynoworks has reported finding almost no significant power increase with these so called "high flow" air filters in his dyno tests.
 
 

It is important to note he did mention in a post that removing the foam at the top of the tank was good for 3-4 Hp. Seems like it is the restriction instead of the air filter.
 
Edit: It was Nels via @Norcal616 and 4-5 Hp.
 

Pulling the foam netted an extra 4-5hp and provided better/smoother AFR numbers... All the foam does is muffle the intake/top end noises at the cost of performance...