airbox benefits

[leafman60]

Ok, I hate to dredge up an old thread butttttttt> Ive been considering elimination of my airbox. Upon greater reflection, I am not so sure that pods OR an open box top is best. I am thinking retention of the closed box, streamlining its internals and creating better ducting to it may be the best. The idea is to create a higher pressure environment from which the engine intake can pull. A pressurized box would accomplish this. Opening the top eliminates the capability to pressurize the box. Attaching pods places them in a negative air pressure environment in the passing flow of moving air. What do you technical heads think?

[callison]

Unless you're going to add a blower to actually pressurize the box, you won't see any significant (or perhaps any discernable) difference. Even a ram air setup won't provide any benefits until you're well up in the triple digit mph range, not useful for street driving in any form. The only passive things that can be done are to reduce the impediment to air flow and providing a larger plenum for the throttle bodies to draw from. There isn't a larger plenum then the great outdoors though, so theoretically, the pods are superior to the airbox. The airbox might be technically superior for weather resistance and noise though. I used to run foam sox on my RD-350. When it rained, they'd get soaked to the point where I would have to stop, reach down, and squeeze the water out. On my R65, even with a stock airbox, in heavy downpour, the element would get wet and I would have to stop by the side of the road, remove the air filter and squeeze it out before the bike would run. The airbox design on the V11 Sport/Sport 1100's doesn't allow for this to happen, which a technical plus if you ride in inclement weather. The downside is resonance and a lack of volume. The Sport 1100's (carburated) were notorious for a flat spot because of ae resonance in the airbox. The same airbox performs better on the Sport 1100i's only because EFI can be programmed to accomodate the resonance (not that MG did a very good job in this regard) but the resonance still affects performance. If the airbox were larger, the resonance problem would probably not occur, but making a large airbox on a motorcycle is a nasty engineering challenge. Because of requirements to accommodate noise regulations, EFI etc, airboxes have grown in size, typically sculpting their addtional volume out of the gas tank volume. Hence, reduced range on modern bikes because the fuel tank capacity is diminished.

[Guest Tmartin]

See the link below. I have been using these intakes for 2 years. Never measured power output but they do make slightly more noise at full throttle. I figure that they are good for at least 37.8 additional horsepower or maybe even more when the tide is in.

 

http://www.guzzitech.com/sewerramair-tracy.html

[al_roethlisberger]

As Carl said, technically a larger airbox will perform better by creating a large reserve of still air, thereby reducing another variable in intake characteristics, and delivering a consistent air charge. But also as Carl points out, the challenge with making a large airbox, especially with our bikes, is the lack of space.

 

The current airbox for the V11 Sport, while serviceable, isn't large enough for the application, and the plumbing is less than efficient.

 

So, one has two alternatives:

 

1) Do whatever one can do to increase airbox volume. Increasing the length of the intake runners like the discontinued Evoluzione kit is one example.

 

2) Remove the airbox, and use individual filters or remove the lid. Given the relatively still air above the fuel-tank, removing the lid may be the best compromise with using the bottom of the airbox to control air turbulance, while opening up the box volume.

 

It's hard to say what works best, especially when with EFI we all can tune the system to optimize performance based on the different configurations.

 

 

Good luck, any of the options above can and will deliver similar performance.

 

al

[dlaing]

My Opinion differs from Carl's.

I have little to back it up scientifically, but it seems fairly obvious to me that if the airbox were more streamlined, larger, was designed to keep water out, heat out, pressure in, and had LARGE forward facing inlets that fed the air into decreaing diameters of piping, it would be a major improvement and I'd pay over a $100 per percentage of power gained!

Don't look for huge gains, but I'll bet you could get an extra 5MPH top speed and the bike would have less trouble facing headwinds.

The scientific evidence is not clear.

The web has posted a lot of negative suppositions from people who would know like aeronautical engineers. I presume they base their statements on failed ram air intakes of factory bikes, and knowledge of aerodynamics oftened gleaned from aiirplane experience where the true gains in air pressure do not arrive until very high speeds.

I believe that they have failed to take into account that decreasing intake diameters( megaphone) and the fact that the engine is pulling air through, can actually result in air speeds greater than vehicle speed.

Other evidence is a web site that showed that ram air on I believe Kawasakis high speed contender actually works and increases top speed.

Another web site gave some evidence that the lidless stock airbox on V11s out performs pods. Pods however have great aethetics, allow for more power than stock, and take up much less room.

Looking at the stock airbox makes me think there is nothing to do but improve it.

Tracy Martin Certainly reduced the bottleneck and gave it a more forward facing inlet.

I would a pair of huge forward facing pods,embedded in a megaphone, a crossover similar to the Stucci exhaust, but on the intake side, something to reduce turbulence like forcing the air through many smaller pipes. I don't think an expansion chamber is necessary.

Get a Power Commander and get a customized map.

Go for it!, and post before and after dyno runs from a wind tunnel dyno.

[callison]

I based my reply on what the Guzzi Land Speed Record Team tried. Personally, I don't think the gains in performance of a super large airbox with forward facing horns will outweigh the loss of esthetics. On a race bike, where form follows function, it makes sense. Tracy's sewer ram air is functionally the same as the intakes found on the Sport 1100's. While the Sport 1100's fairing does provide some improvement, it apparently isn't optimal as DaS MotoTec offers yet another fairing modification to move those inlets and make them larger. From a practical standpoint, endless amounts of money thrown at improving a Guzzi will make it only marginally competitive against the current crop of much less expensive bikes available elsewhere. What I love about my bike(s) is the feel, the sound, and the looks. Performance is really a lesser concern out of the many aspects of owning a Moto Guzzi.

[Steve G.]

It seems to me that where the snorkels are facing on this air box, the air is not clean, meaning it is not air that is smooth and uninterupted. It has the front forks, the oil filter, frame cross brace. So, to take advantage of the air to force feed it into the main box, to increase the air box pressure, you would have to put extentions to the current snorkels which reach out to the furthest point of the bike. Then you would have to be doing at least 100 mph for all this "ugly" ducting to make an effect. Think about it, look at a Hyabusa, zx12, zx10, and of thos things. Where is the air intake? At the very front of a highly wind tunnel designed fairing, sometimes actually using the frame of the bike as a conduite for the high pressure air.

What I and [i think] most other V11 Lemans/Sport owners are looking for is midrange, which is what these engines are all about. So forget the snorkel mods. It has to be about the amount of air the filter/airbox can move, and the K&N filter in the factory air box, or the one by Fer racci. I do seem to remember that the Ferracci air box has eliminated the snorkel thing altogether, which can tell you that the snorkels are more for EPA intake noise reduction, and nothing else.

So, I think one should go down to the auto parts place and get a K&N filter, and modify the top of the box. Or if you don't want to do that, do what I'm thinking of doing. Get another air box top, and modify it, cut the snorkels off, drill it with holes, in other words just use it as a means to hold the filter in place.

Ciao, Steve G.

[Janusz]

I think that one could easily discard all teoretical ramblings and just try the simplest and therefore most elegant solution already recommended by Ferraci;

Next time when you have your tank off just unscrew the airbox top and put it on the shelf. Then ride the bike and see if you like it. I did.

 

If you do not like it you can always install your airbox top back.

 

If you see clearly that it is an obvious improvement (most likely scenario) then you get from ferraci the brackets preventing your filter from flying off, inrease fuelling with PC and just enjoy better sound and performance.

[Guest guest_Mike Stewart]

I too am a believer in ram air, here is an interesting aritcle that is a few years old about the subject.

 

http://www.xs4all.nl/~zx11/uk3.htm

 

Happy New Year,

Mike

[Guest dkgross]

janusz...is it really that simple?? Just pop the top of the airbox off?? Wow..I might have to try that.

 

I'm getting my Mistrals/XOver in a week or so, and Micha and I were discussing what 'other' things we might want to do with the beast

[Gio]

I considered the various options but wanted to retain the air-box body and associated side panels, avoid potential problems of pods (I often ride in the rain) and retain the use of the K&N filter I had already purchased. So my solution was to cut-off the snorkels (right back to the box body) and drill the airbox lid.

 

The result was a noticeable improvement in response and to my ears at least, a nice increase in intake noise when wide open.

 

Gio

[Janusz]

janusz...is it really that simple?? Just pop the top of the airbox off??

Yes !

[Guest dkgross]

janus..got any photos?

 

am I safe in assuming that once the pipes/xover are on (I'm thinking about putting a K&N Filter on as well), that if I do pop the airbox lid off, all I need for Micha to do is tweak the PCIII properly?

 

that would be great I'm really not sure I want to go the Pods route yet..but..hell..I could be convinced...

 

I sure wish there were an official PowerCommander Dyno center in Seattle. Whaaaa.