Custom Air Intake Project

The one thing that I have learned in my time as an owner of the Silverwing is that maximum airflow is crucial to good performance and extremely crucial to obtain maximal fuel mileage. Many of you probably read my post about removing the air intake cover and running with the air cleaner exposed and how it yielded an increase in 2 MPG on interstate runs. Now, while I was very happy for the gain.... I am not wanting to leave the air filter exposed to the elements. So I have been thinking about the best way to get more air into the swing and here is what I've decided to do.

1. I already have a K&N installed (A stock air filter could potentially limit the effect of this mod but I suspect would still be beneficial but probably just a little less so. Below is a pic of the air filter on my bike when I bought it. It had been sitting in a barn during the drought years of 2005-2009 and was thoroughly kegged in dust and black gobblety goo! This is why my bike was getting 35 interstate miles to the gallon when I bought it back in Feb 2009. Gained just short of 5 MPG when I put a new one on. Gross! I have never come close to letting any filter get like this and would be embarrassed if I did!




2. The plan is two fold. I am going to cut a large rectangular notch (8.5 inches by 2.5 inches) in the side of the air filter cover to approximate running without a cover. I am going to use the wire mesh off the back of a stock air filter which I simply removed by cutting of four plastic tabs with a razor knife and use this to cover the opening which will hopefully allow a good amount of airflow without allowing in any large contaminants/elements. You will notice that there are already 4 holes in the wire mesh cover. I am going to use a drill press and make 4 more holes, 1 in each corner. You can see from the picture below approximately what this will look like.


I will finish off by painting the wire mesh cover in black and securing to the air filter cover using 8 small black screws. The wire mesh cover will contour to the shape of the air filter housing quite well. Black silicone could be used to seal any gaps if any exist which is probably what I will useif necessary, but I dont expect any gaps based on what I've seen with how the wire mesh cover seems to contour.

3. The next part involves removing the stock air tube inlet and reaming out the hole to an even 2 inches. It is my feeling that the stock air tube inlet is highly restrictive and serves very little practical benefit in terms of delivering life giving air to the engine of the Swing which is why I'm employing this step. I believe this will flow more air in. Next, I purchased a 2 inch flanged drain inlet from the plumbing aisle at Lowes Home Improvement. Once the hole is drilled, I will insert the flanged drain inlet from the inside so that the tube is on the outside with the flange pushed up against the inside of the air box cover. I am also going to try and alternate mounting with the tube going to the inside and the flange to the outside to see if their is any difference with the flow. Whichever method I use, I will finish off by using black silicone to seal the flanged tube to the air housing cover. Below is a pick of what the air housing cover looks like and an idea of how it will look on the air filter housing. I've not yet reamed out the hole so I can't yet mount it with it pushed in but this will give you an idea.


My hope is that this will flow much more air. However, it is important to have smooth flow and no vortex effect or mass disturbance of airflow. This is a factor that I can't yet account for until I test it. A guy at a motorcycle shop says he can simulate the effect by using smoke once I make the mod so I will probably take him up on his offer to see if we can see how the air is flowing. I will complete this mod within a couple of weeks hopefully. As soon as I have any results... I will report those back on here as well. I am hoping this will work and be a viable solution to many who want to get more air flow into the bike without having to worry about want might be getting in. Oh well, that's all for now.

Ron, My hat is off to you. I hope this all works. Thank you.

I am very interested in your outcome Dennis, please let me know how much improvement you get. I bought my 2008 new in march of this year and have put close to 20k on it, (the cold weather is slowing me down a bit), but i am getting around 50 mpg with wife and i both on it. It seems when i take long trips by myself even cruising between 80 and 85 i get close to 60 mpg after the second fillup of the day. I'll be watching for your results. good luck.

Hi Jim, No...I'm not the person doing this, It's Ron.

Hi Jim,

I'll definitely post my results. You state you are logging 60 MPG on the interstate riding by yourself at 80+. If that is accurate, that is phenomenal and I wouldn't touch that bike at all. Even 50 on the interstate is still extremely good. I know there are many who have averaged 55 or upper 50's with mixed riding but usually fall well below 50 when on the interstate. I usually average about 42 MPG on the interstate riding about 70-75 and low 50's with mixed riding. I am hoping that in the spring, when I put my stock windshield back on and take off the bigger GIVI that I can reach 45 MPG on the interstate and run mid fifties riding two up. Will keep ya'll posted!

Ron,

Do I understand that the gist of your mod to is to create a window in the air cleaner housing cover that is slightly smaller than the OEM filter element metal screen & mesh --and then cover that 'window' with that same mesh & screen after removing it from an old OEM filter?

If I got that one correct, I'm not sure exactly what you're doing with opening up the inlet tube hole to 2"--and then restricting it again by installing a (pvc / abs) pipe fitting.

Seems to me that creating that window will allow much greater air flow (vs doing multiple 1/2" holes and certainly vs OEM configuration) so as to render any inlet tube mods moot.

That being said, I've only changed my air filter once, and so don't have ready visual familiarization with that inlet tube, it's position and function under stock circumstances.

Best wishes for a merry Christmas

Tim
'03 Silverwing, Cosmic Jumper
Philadelphia

Ron, I am impressed with your well thought out plan, however counter productive some of it may be. That said, I would be much more cautious in doing your modification to that degree all at once. Have done air intake mods on many dirt bikes & sport quads over the years I have found that improving air flow can result in a case of diminishing return, i.e. by doing more than can be accommodated by additional fuel flow. That seemed to be the case on carbed engines and in regard to the EFI S'Wing, I'd be surprised if it could be done without remapping the EFI in order to prevent a serious lean condition in the engine, resulting in over heating, piston or cylinder wall damage, or worse .
If I were to do it all again, I think I would again just get a 3/4 or 1" hole saw or drill bit and drill the cover with two holes at each end of the cover and the road test it for performance or if you have access to a dyno run the bike before & after the drilling & assess the benefits. I noticed a big difference using this air flow improvement and have seen no indication of a lean condition either in the plugs or in engine temp.
Just my thoughts and opinions

I'd say drill 1" holes and remove the air inlet should be plenty.

42mpg at 70-75mph seems pretty low to me, my Goldwing 1500 can match that. I wonder if there's a problem with the fuel injection, perhaps one of the sensors has died putting the ECU into limp home mode?

Cosmic,

Yes, you're understanding is correct on both openings. The reason I am enlarging the hole that holds the stock air inlet is 1. to give the abililty to flow more air 2. to give me some tuning options to adjust flow rate, amount, & control vortex. The stock inlet tube is very restrictive and runs about 5 inches or so into the air inlet box with the opening angling down at 45 degrees n the direction of the air filter. The pvc piece that I have could be used in several ways. The first way is with the tubed part facing outwards and the other is with the tube facing inwards. Or.... if not needed.... I could block it off all together. It will take some time and testing to figure out which configuration will work best. The main thing is that air needs to flow smoothly and not be "helter skelter" in side the box. So I really view this portion of the mod as a "dial" for optimizing/smoothing the flow and is really more of a tuning option rather than lets see if we can squeeze in more air option. Even so, the inside diamter of the 2 inch pipe is much larger than the diamter of the stock inlet tube so it should allow in more air if I think it's necessary.

I don't believe the large piece of mesh screen that I am using would be any different than those who have cut many large holes into the side of their air cover. All my method is designed to do is put smaller openings in place of larger 1 inch or 3/4 inch holes but still flow good air. I'd almost bet that 4 or 5 larger 1 inch holes would flow more air than my configuration due to the smaller holes. Think of what might potentially come through those 1 inch or 3/4 inch holes as compared to the smaller ones on the wire mesh screen. While the air filter would almost certainly prevent anything from getting into the engine, I simply feel a little more comfortable with the smaller openings.

I am almost done with the mod. I simply need to screw the wire mesh cover back onto the box and we're good to go. Then I'll be able to start doing some testing. I did make one change to the initial design. Rather than use black paint on the wire mesh cover, I used rubberized undercoating for a more durable finish. More to come.

It would be interesting if someone had a vacuum gauge that could be connected to the air intake right behind the filter before and after drilling the box or otherwise modifying it. A quantative measure of the difference before and after would be interesting.

Drilled my five 1/2'' holes today, if I was to do it over, I would drill where the holes that are in front of filter.

Project is completed. Due to freezing icy mix, no opportunity to test so that will have to wait. I consulted with 2 motorcycle mechanics today and showed them my customized air inlet along with the stock configuration for comparison. The first mechanic (a honda mechanic here in town) said absolutely no problem whatsoever. He simply stated that I should be careful to try and make sure that water does not enter in. The second mechanic is the guy who does my work for me and works on all makes and models. He said that while it will lean it out some, he believes that the bike should respond to it fine and sees no need for concern. He stated that if I was doing an exhaust modification in addition to this,that we would need to make some alterations using my power commander. He told me to take it for a 30-60 minute ride and check both the plugs and the tip of the exhaust for whitening just to be sure for peace of mind. He said any problems would present themselves by then if there were any issues with a lean condition. He also said that when you test, be sure not to let the bike idle at the end of the test as bikes run rich at idle potentially masking a lean condition indicated by the plugs. Another note of interest, I think..... the later Silver Wings have an Oxygen sensor. If this is the case.... he said that you guys who have the bikes with the O2 Sensor have nothing to worry about at all and that the engine would automatically compensate for this change. Here are some pictures below of the completed mod....

Nice!!

Looks good Ron! Nice tidy job.
Hope it works as good as it looks, if so you got it made!

Wes