Air Filters - the real deal.

[Syler]

OK, forget all the advertised power gains of the common filter mods. Does anyone know the surface area of the K&N drop in filters vs the aftermarket such as the cone type?

Also, I haven't looked at the stock box but it appears that most cone type filters just send the air into the stock box which depending on design might not be the most free flowing. In fact, many are designed to reduce noise and are quite restrictive. Putting a fancy filter on such a box does nothing.

Without taking things apart yet, are any of these aftermarket filters A) known to have more surface area than the stock ones, B) employing any type of smooth free flowing intakes?

If bike upgrades are like car upgrades which I assume they are, it wouldn't suprize me to see filters costing hundreds that do a worse job than a set of K&N drop in types and a drilled air box.

[BAD BOY M109R]

the ones I have alot of surface area....

[Stag Fury]

If I understand your questions correctly, you are basically asking whether there is any real advantage of an open air cone filter system over the stock box with a K&N element. My answer would be yes. Not sure about the total actual filter element area, but the total effective area - the filter area that is exposed to the open air - is definitely greater with a cone filter. Not only is this type of system going to intake a larger volume of air, but also the temperature of that air is lower than that of a stock box. The opening to the stock box filter is right next to the cylinder heads, where hot air lives. The cooler the air temp, the more condensed that same volume of air is. The more condensed the air inducted into a combustion chamber, the bigger the bang. So an optimal air intake system will be one that allows for an increased volume of air plus a more condensed air mass.

Hope this helps answer your questions. If, on the other hand, I just killed a fly with a sledge hammer, my apologies.

[AlmostDivorced]

If I understand your questions correctly, you are basically asking whether there is any real advantage of an open air cone filter system over the stock box with a K&N element. My answer would be yes. Not sure about the total actual filter element area, but the total effective area - the filter area that is exposed to the open air - is definitely greater with a cone filter. Not only is this type of system going to intake a larger volume of air, but also the temperature of that air is lower than that of a stock box. The opening to the stock box filter is right next to the cylinder heads, where hot air lives. The cooler the air temp, the more condensed that same volume of air is. The more condensed the air inducted into a combustion chamber, the bigger the bang. So an optimal air intake system will be one that allows for an increased volume of air plus a more condensed air mass.

Hope this helps answer your questions. If, on the other hand, I just killed a fly with a sledge hammer, my apologies.

Totally agree with Stag Fury on this one- for instance I have a set of the tornado cone filters ad the flow a ton of air. They point forward and are away from the engine inhibiting extra cool area- I would say way more then stock w/kn. Put the real test to the track an it's probably only 10ths of a sec overall like most mods. Not practical for most but if your going for a certain look then there ya go.

[Latinrascal]

This has been kicked around a lot on this board and it has been proven that there is only so much air that can be sucked into the air intake system on the 9 because of the snorkle type breather hoses and under tank airbox. so regardless of the type of filters you put on they will make out on air flow. I had my bike dynoed with (listed by most power gained) no air filter, Holley/edlebrock air filter, stock bowls cut with k&n's, homemade bottle fed with spectre cone filters, stock filter cut bowls, stock setup. Between the Holley setup and spectre filters there was not a while lot of difference on power gained. Hope this helps.

[MATT'sADDICTION]

This has been kicked around a lot on this board and it has been proven that there is only so much air that can be sucked into the air intake system on the 9 because of the snorkle type breather hoses and under tank airbox. so regardless of the type of filters you put on they will make out on air flow. I had my bike dynoed with (listed by most power gained) no air filter, Holley/edlebrock air filter, stock bowls cut with k&n's, homemade bottle fed with spectre cone filters, stock filter cut bowls, stock setup. Between the Holley setup and spectre filters there was not a while lot of difference on power gained. Hope this helps.

Great info except for one missing element that we all want to know. The numbers. At least as close as you can remember. I have cut bowls and K&Ns with extra filter element fabricated into the top of the filters. The reason I went this route is because one day I was cleaning my filters and decided to go for a short ride and see if I could feel any difference without any filter. I have the PowerPro so I figured it would quickly compensate for more air if it was actually getting more air.

I thought I could feel a difference. I did several high spirited sprints and decided if it was pulling harder without the filters, then maybe more filter area would allow more air. So, I did the mod where you cut out the top rubber on the K&Ns and replace with filter media. I really think it made a little difference. Which would coincide with your claims of the Holley being the next best to no filter.

Your experiment and findings are going to really tick off all those bottle fed cone filter guys. Do you think it had more to do with the homemade design? Or, was your filter element on the bottle fed a cheap K&N knock off that perhaps didn't flow as well? Which is really no different than the cheap imported cone filters-- I would think.

Any thoughts?

[Latinrascal]

Great info except for one missing element that we all want to know. The numbers. At least as close as you can remember. I have cut bowls and K&Ns with extra filter element fabricated into the top of the filters. The reason I went this route is because one day I was cleaning my filters and decided to go for a short ride and see if I could feel any difference without any filter. I have the PowerPro so I figured it would quickly compensate for more air if it was actually getting more air.

I thought I could feel a difference. I did several high spirited sprints and decided if it was pulling harder without the filters, then maybe more filter area would allow more air. So, I did the mod where you cut out the top rubber on the K&Ns and replace with filter media. I really think it made a little difference. Which would coincide with your claims of the Holley being the next best to no filter.

Your experiment and findings are going to really tick off all those bottle fed cone filter guys. Do you think it had more to do with the homemade design? Or, was your filter element on the bottle fed a cheap K&N knock off that perhaps didn't flow as well? Which is really no different than the cheap imported cone filters-- I would think.

Any thoughts?

With the setup I'm running now(picture below) I am putting down 127hp to the rear wheel. Without the filter it put down something like 130. With stock setup it was something like 118 or so don't quite remember. Anyway there wasn't a big difference for me between my setups. The cone filter I used is a comparable to the k&n's. They are called spectra or specter or something similar. I decided on my custom cut set because I preferred the look. I looked for all my sheets a while back but it appears that they didn't make the transfer to the new pc or more likely I just don't know where to look,(I'm pc illiterate). I'm not trying to start a debate or step on toes, I'm just sharing the info that I had from running my air intake experiments. I'm sure there are others on here that could help a bit more then I am gonna be able to. As I said there was a bit of difference between this setups but it was so minimal that I feel it would hardly be of significance.

Oh and between the bottle fed and custom cut they were so close it was up to looks as they both performed almost identically. I think I remember the cut covers having 1 more foot pound of torque over the bottle fed but the same HP but I am going on total memory here and that was a few years ago before I have been pumped full of these Damm drugs! So who knows, lol.

[Flanker]

I would tend to agree with you on the drop in K & Ns. Wouldn't be surprised if they flow more air (in CFM) than the stock motor can use.

[Syler]

I am experienced with tuning carsbut unfamiliar with the intake setup until I get a chance to pull it apart.has anyone tried eliminating the box and just using some silicone bends? Also, no idea what bottle fed means. I assume cut bowls referres to the covers? Where are the filters anyway?

[Latinrascal]

I am experienced with tuning carsbut unfamiliar with the intake setup until I get a chance to pull it apart.has anyone tried eliminating the box and just using some silicone bends? Also, no idea what bottle fed means. I assume cut bowls referres to the covers? Where are the filters anyway?

Yes way back at least one member (more like 3 or 4 members involved) here went full on mad scientist and tried to remove the entire air box and replace it with k&n's right to the throttle bodies. If I remember correctly he had a hell of a time getting the bike to run right and lost power in the process.

Bottle fed refers the cone style filter pods at the end of the snorkle tubes comming directly from under the tank eliminating the stock exterior air boxes. Stock filters are inside the chrome dome covers on each side of bike motor.

[Latinrascal]

I would tend to agree with you on the drop in K & Ns. Wouldn't be surprised if they flow more air (in CFM) than the stock motor can use.

I would be more inclined to state that the k&n's flow more air then the stock air box (under tank) can handle. I beleive the motor could pull all the air they could get from them and ask for more! but this is just mye guess as I have no evidence to support that statement.

[MATT'sADDICTION]

There's a thread here somewhere, I thnk it can be found in the how to section that shows how a member came up with the idea of cutting the top rubber out of the K&Ns and replacing with more filter to get more cfm. If I remember he did some before and after pulls on the Dyno and did pick up a few more ponies over the stock K&Ns. That's why I decided to give it a go.

My biggest concern with the $200 cone filter kit is whether those filters are actually more restrictive than some stock K&Ns. They look great. Maybe there is a conical K&N that will bolt on to the tube. Then for a few hundred you would have a pretty sweet setup.

[Syler]

If changing intake caused the tune to be off, it most likely was effective. The right tune is of course required. There is more to air flow than the CDMA of the filter. There is also a matter of smoothing out the flow and the right volosity.