Staplebox wrote on 03/12/09 at 18:57:02:


Sure but it might look a little different on my bike than yours cause of some other mods I've done.  I'll try to get a pic tonight.  The wife and I are painting the laundry room at the moment... well, she is... I'm helping!

Looks like I've got the final product for my bike.  I used some PVC fittings to make this.  I tried it out a few minutes ago and it seems to provide a little more power in the upper midrange and high rpms than the previous design but that could just be placebo effect, weather or both.  This design does have about a 20-25% larger external opening than the previous containter/screw cap and, unlike the other design, has a tapered internal opening for smoother airlfow in.  The larger opening I feel is better for the higher air flow needs when riding at higher rpms.  It also gives me another 5/8" of tube length to further help with developing a good laminar flow.  








I've got a couple of different internal screens that I might experiment with to see if they make any difference.  

 This mod sounds like it has great potential so far.

  I'd really like to see this done to a stock bike , etc... no carb or muffler mods, and see what performance it would add.

Here's why I think the Kamikaze mod works better than the airbox setup or a pod filter mounted directly to the carb.  

The first pic below shows the air pathway in stock form.  As you can see there are some serious bends the air has to make to get to the carb.  This adds resistance.  Turbulence created by this path, however, does get resolved in the tube prior to the air entering the carb mouth.  

The second pic shows air pathway with pod filter mounted as usual.  There is a small amount of turbulence as the air makes the curve from filter to the carb inlet.  Then once in the carb venturi, the air begins the pressure/velocity changes and turbulence begins to resolve as the air passes over the jets.  In this diagram I think the smoothing of the air and the vacuum effect is just getting established at the point that it should be pulling gas through the jets and being emulsified.  

The third pic shows less air turbulence as the air enters the tube due to less air bending than with a pod filter.  Then the pressure/velocity changes, which are needed for the carb to work best, as well as turbulence reduction occurs in the tube- rather than starting to occur in the carb venturi as with the pod filter mounted on the carb mouth.  When the air passes through the the tube and then carb venturi, the pressure/velocity changes have already occurred prior to entering the carb.  The air passing through the carb venturi is smooth and more effective at drawing gas up through the jets and a better emulsification of the air/gas mixture is achieved.    



Now, all you geniuses and carb gurus out there, tell me where you think my theory is wrong or questionable and how I can make it even better.

Jim,

Using the stock rubber long intake stack to get the Suzuki tuned "ram boost" is a good idea.  Keeping the air resistance through the filter media very low is a good idea.  Having lots of carrying capacity and a fine dust removal rate and a nice long service life between having to mess with the filter is a good idea.   Having as many of the above as you can get makes the overall good idea even better.

Last mountain trip I put aside the idea of putting on the loud Harley muffer that is sitting over in the corner of my computer room as I type because I realized that I really didn't care all that much for all the loud snarly blatts and pops that come with that particular turf.

And I also realized that these performance maxed rejetted constantly fiddled with constantly retuned bikes I was riding with weren't leaving me behind at all.  Quite the opposite, on the way back just to prove the point to myself I set the maximum interstate pace my old stockish looking wee bagger could do.  Lancer kept up and passed me, but he was running his dual spark plug mod at the time so that wasn't surprising.  Everyone else lagged behind.  Some were miles behind.

Real world performance isn't about noise and it isn't about "maxing" this or that -- it is about balanced performance over the range you are working with.  Perhaps on that particular rain threatening day at that high mountain altitude my bike's this and that lined up in alignment with the mountain Karma forces better than the exhaust modded bikes did -- I dunno.  

But noisy and radical wasn't making any real power that exceeded quieter and more reasonable on that particular day.

As for your mod it is interesting and potentially very useful to the bobber and minimalists among us.  It looks good and it saves some of the ram-tuned performance elements they may have given up previously.  You need to run it a while and find out the rest of the story is and fix whatever that might be.  

On mine you had to sew the element lightly around the edges to keep the air box air blast from peeling it apart -- that was discovered after some use time.   You may discover your time to fill up the filter media is short and you need a certain yet to be discovered cleaning frequency.

You are using a very thin media with a small surface area.   Air velocity and rate of flow thru the media material is relatively high.  How are you stopping all the very fine dust like stuff?  If you don't trap it and hold it somehow some of it will bounce on through the thin filter and wind up in your engine oil.  

K&N uses their version of canola oil and I use Mazola frying pan spray (sticky like nobody's business) which traps the little stuff on a contact basis as the air bounces through some depth of material.  K&N tries to substitute folded surface area for depth (and that is debatable - I prefer inches of serial fiber depth for my depth)  

Both K&N and I depend on total fiber count to collide with, catch and hold a goodly total amount of trapped fine stuff (and I have a lot more material depth and fiber count available to me compared to K&N).   K&N has determined their cleaning frequency and I have mine doped out to a clean it and relube it once every 2 years when using the 2" thick Nu-foam batting.

You are proposing a very intentionally minimalist system that has some trade offs built into it -- perhaps you should stop and explain to the new folks what your filter will stop, what it won't stop and how frequently it will need attention to keep their engine healthy.

Our filter philosophy is totally different and we serve different segments of the list -- yours is bobberish and performance oriented and mine is the "we want it cheap, we want it to work well and we don't want to have to mess with it any more than we have to, preferably never".   Not much overlap in our audiences, really.  

My audience is old and radically lazy, actually.  Right cheap too.  Yoda-like old and wise and right tight with their bucks.   Yours is young and enthusiastic.  Luke Skywalker let's go toss a firecracker down the exhaust pipe and blow up the reactor enthusiastic.  That's OK, I am just jealous of their energy levels and how much they are willing to take on at a given time.

You got you a good idea -- keep after it as it looks very useful to the bobber folks who need good looks first, then bike performance as second, then fine filtration and long filter service life as a distant third.  Just  be clear for the newbies exactly what they are getting with your system and what the trade offs actually are.

Oldfeller

Oldfeller, those are some great points.  Thanks you so much for the  feedback.  I think this idea is an evolution of what I see and what you all see and recommend.  Your experience lets you see things in ways that I may not have seen or thought of.  That's why I value everyone's feedback.  I keep finding little ways to improve it as do all of you.  It might turn out to work great as is.  It might turn out to need a 1" larger opening plus a dust cover over the opening, a double filtration system if you will, during the hot, dry summer months for the overall best mix of performance, effectiveness and ease of use.  

I am now using the filter material that was in my cone filter.  It is double layered.  I also washed and dried a white dryer sheet and have that on top of the filter media. It introduces minimal resistance but color change will help indicate intervals needed between media changes.  I can periodically pull out the dryer sheet specimen, lay it on a clean, unused dryer sheet and observe for color change.  I'll take pics and post so you all can see as well.  It may not be the most scientific method but I feel it will be effective none the less.  There are two things I know for sure- it can continue to be improved upon some how and I know I ain't going back to the airbox or pod filter after experiencing riding with it.   

Thumper, let me fine tune this setup first. Making it ram air will give me a whole new dish of dynamics to have to solve!

Here's another design I threw together in about 5 minutes.  I had the rubber piece already and saw the metal cup in the house and viola.  I'll wrap it with filter material then put a unifilter over it.  The bottom is solid so I might open it up and put a screen in there as well so it will still have some direct flow benefit.  The positive thing about this is that there is more surface area for the air to pass through and, as others have pointed out, longer times between filter changes.  The negative things, in respect to the previous design, is that even with the bottom opened up some of the air still has to bend upon entry and the tube length may be a little too short for developing a good pressure change.  I did insert a piece of tapered PVC for a ventrui effect so that will help with vacuum some.  It is about the same overall length at the white capped one pictured a few posts earlier.  Anyhow, I don't know how it will work.  It's raining today, I was bored and found myself wondering what a difference a shorter tube and more airflow area would do.