Latest OCMD project: modded airbox lid
 

Here are some pics of my modded airbox lid with integrated filter (K&N unit for Kawi Z1000). Note that the shield on the inside can be removed (will likely try it with and without).

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Is the shield just there to help channel air flow to the stacks? Do you think the potential performance benefits will be noticeable?

yes, the shield is there to route the air (and reduce turbulence; the cutout is is the exact same radius as the front cylinder velocity stack, which is nearby). As for benefits, Roger Ditchfield (Revolution Racing in the UK) has tuned a great many Stage 1 VTRs with a lidless configuration (trim the lid to only keep a retaining ring), running a K&N filter and reports very significant gains in performance. This is based on that idea (reducing intake air obstruction/flow limitation caused by snorkel) but goes one further by also clearing up the area around the velocity stack bellmouths (a critical area from what I have read), giving them an uncluttered area to get their air. Finally, by retaining part of the lid, it also significantly increases the "post-filter volume" (which should, again, improve engine breathing). On paper, it all works.... the truth will be when the weather gets warmer adn I fire it up. I have a spare set of carbs that I will be setting up with "ballpark settings" based on what I am running now (go richer across the board), which, I hope, will get me close to final settings. I can't see it NOT working unless there are some serious turbulence issues at work.......

That looks good! I really like your shield idea. Sorry I haven't posted mine up yet. Work got in the way and I was out of state and away from the bike for a while. Just got back home Friday.

I'll post some pictures up this evening. I promise! Mine looks like yours, but I have a rectangle K&N filter. I never found any honeycomb material, so it was never installed.

I now have two completely different airboxes (stock & lid mounted filter) to test with my Vaypor gauge. It will be really cool to see if there is any improvement!

This is my 2nd gen shield; the first was a lot like the MWR shield (that is, it had the same countour as the filter, but was raised about 1.25" off the filter medium). However, this had the plate right over the entry to the front cylinder bellmouth, so I decided to head back to the drawing board and create a "sealed" chamber over the front portion of the filter, thereby reducing any potential turblence and feeding the air directly to the stacks. Not sure how it will work, but hey, it took me one evening of playing around so it's no big deal if it doesn't fly.....

My main reason for using a triangluar filter was to try to mimick a NACA-duct (narrow at the point of entry), in the hope of facilitating air intake (especially at low speed, so as not to create a boggy low-end).... I am likely trading off some filter area in the process, but I will gladly trade 2-3 hp at the top-end for an extra 2-3 ft-lb at 4K rpm (especially seeing as how this high-flow set-up should boost top-end anyhow)....

Rain resistance?
 

How about riding in the rain or very dusty conditions? Seems the fairing will shield some but the negative air created by the carbs may literally drown them.

it draws air from under the tank, mostly from the front (essentially the same area as the snorkel does with the stock airbox), and is covered up. I will have the front of the tank raised slightly, but am already running it this way due to spacer under filter. Besides, if it's not a problem with a lid-less set-up like Roger uses, I failt to see why it would be with this..... It may be an issue in a torrential downpour, but then all kinds of things can become an issue then (usually electrical in nature).......

You know, I was looking at this extra airbox and thinking...how cool would it be to cut a hole in the side of the airbox and replace it with plexiglass. Then, cut about a dozen pieces of string and tape them to the inside of the airbox and then put my Shopvac in place of where a carb would be. Just to see what happens inside. Where turbulence is, if any. But, there is so many variables, it would never be the same as actually riding the bike.

After dinner tonight I'll take some pictures of my lid and post 'em up.

Do a plexiglass side, then tape an iPhone to it and start the video... Then go riding....

Every once in a while yell out the speed, so we know what is happening at each speed :):)


James

If I remember correctly, in the testing I have done previously, anytime you reduce filter area, you reduce flow, thereby reducing air intake, thereby reducing horsepower.

I am VERY interested in the lidless idea, especially keeping the outer edge to hold the filter in place. This could be easily made with an air cutoff tool and simple cleanup with a dremel....

Honestly I wasn't planning to mod my VTR for horsepower anymore than it already is, because it functions so well and wheelies whenever I want, but... These simple, free mods may get the best of me!!!

On to my search for the lidless airbox thread.... sigh


James

an engine is an air pump... if the air can't get in, it can't make power. However, int he case of the VTR, the biggest filter in the world won't overcome the bottleneck, which is getting air into the airbox itself (ie. the snorkel). This is precisely the reason that Roger D sets up his Stage 1 builds with a lidless box.......

So hook us up with more info on the lidless box.... Pics, links, jetting requirements, etc...


James

Hook up with Roger at the e-mail address provided in the vtr1000.org post......

This is an intriguing idea, you did a nice job modifying the lid for this.

I have a spare lid for my airbox so I may try a similar experiment when it's time to replace my air filter - looking forward to your post about what you experience with this. Has your engine been dyno'd for a baseline?

Flash of brilliance (or insanity, lol)

I was wondering if there would not be some additional benefit to possibility adding a "gate" of sorts at the open end of the air diffuser. One could then use a small stepper motor, working though a likage, to have it open above, say half-throttle. THis would (theoretically) give you better intake velocity at low throttle opening (by limiting the filter area) for better power at low speeds while giving max flow at high speed when the engine can use more air..... I am nil in electronics, but I imagine it couldn't be that hard to split the wire coming off the TPS to get a reading (ie. throttle opening) and have some means to it activating the stepper motor once half-throttle is reached. Alternatively, some form of reverse polarity switch could be mounted on the throttle linkage to get the same result.

thoughts?

The RC51 (RVT) had exactly that set-up OEM (as do others) but many moders eliminated it, some with some wild custom air boxes...

The dreaded "flapper valve"..... not sure how exactly it was set to work (ie. what engine speeds,....) IIRC, it was designed to cut intake growl to pass noise testing.....

Sorry Micky, but I'm having an issue with my phone or possibly with Photobucket. Not sure yet. It won't upload any of the new pictures (started the project, it sat for a while, then finished it). All I have is two pictures that I took in the very beginning. I'm going to try taking some pictures with my wife's iPad tomorrow.

I started with a stock lid that I had previously cut four 1" holes on the sides for an experiment (in case you were wondering what they were), which did NOT work well. Was a big flat spot ~4,500-5,500RPM. The holes were welded up in the finished lid.

I used K&N filter #33-2072, which is roughly 9.5"x7.5". It came with the bike when I bought it. The previous owner kinda hacked something together and made his own K&N filter for the bike (pictured below).

Ever since I started plastic welding, I like using it over adhesives. The chunk of plastic that was removed from the lid wasn't big enough to make the rest of the modification. What I needed was PP (polypropylene). So, I went to my local hardware store and also hobby store, but they only carried PS (polystyrene), which I ended up buying. It was a .08" thick, 10"x12" sheet. I wasn't sure if these two plastics (PP & PS) could be welded together or not, so me, not wanting any piece of this to come apart and get sucked into the engine, I ended up using marine grade epoxy to attach everything together. After sanding it all down, I then used some rubber type of sealant to seal everything. Since the plastic that I purchased was white, I then spray painted the exterior of the lid black. All finished, it looks like it came like that from the factory. What's neat, is cleaning and oiling the filter is still just as easy as before, even though it's permanently fixed to the lid now.

Now, I had to make sure everything is sealed when the airbox is put back together. So, the bottom part of the airbox, I just squeezed a little RTV into the recess that the filter fits onto. It works great as a seal. The lid already has a rubber seal from the factory, so less for me to do. Since you can't just screw the lid onto the airbox without a filter in place (you can, but it won't seal), I just cut one of my filters around the perimeter, leaving about 3/16" of plastic for the lid to sit ontop of.

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I really want to see if there is a payoff for all of this, so I will have these setups to test:
-Stock airbox, stock lid w/snorkel, K&N filter
-Gutted airbox, K&N filter in lid
I also have a factory filter (Pictured above, but at the end of its life though)
And any variation of those above.

I have a Veypor VR3 gauge installed on my Superhawk and it has the capability to figure out horsepower. So, I'm going to use it to see if these different airboxes do any good. As long as I test each airbox one right after another on the same day, the gauge will be able to help me test this stuff. I know it's not as good as a regular dyno, but it should be good enough to see results!

Filter In Lid
The FIL mod? :)

That's what I was going to ask, it seems like the filter area on your FIL mod is a decent amount smaller than the OEM Filter. Won't that hinder the gains your trying to achieve?

I played around with that idea on my race bike when I had the incorrect airbox for the motor swapped in my frame. It sounded cool but would probably not we worth the time, research, and effort. I said to hell with an airbox and got some keihin flatslides ;)

Possibly, but his intake is much larger and he's using a bit higher flowing filter than the stock paper guy.

oh that's right, the snorkel area is much smaller than the OEM Filter, forgot about that.

i can se this being the same to set up as a lidless air box ! keep up the good work guys

I think so too...... as the set-ups are quite similar in principle; that is, in Roger`s "lid-less" set-up, the filter base acts as the lid. Also, in both instances, the filter acts as the sole intake restriction (ie. no snorkel) and the entire airbox volume is post-filter...... However, in both mine and Crux`s "designs" the filter is further removed from the stacks (which should result in improved airflow into the bellmouth) and the internal (actual) airbox volume is greater.

that it should and thats why im interested in the dyno runs .

You`re not alone in that regard, trust me :)

i should be getting mine set up soon tho with a lid for now as that will be removed when i build the stage 1 motor .

In case anybody was curious, Micky & I thought about the FIL (Filter In Lid :) ) mod kinda at the same time. I wasn't copying him or anything! Heck, neither of us know if this will even work well haha. When spring (sometime in late April for me) rolls around, then we can test this stuff out. All in due time.

any progress gentlemen

none here, it`s winter, bike is hibernating...... nothing will happen at my end until April or so....