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What flows best?: stock intake air box or two small aftermarket filters?

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Same huge pile of boiling, supturating, leaky arse! As much use as an ejector seat in a helicopter!

  • Haha 1

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Jeezus... just how clean do you wanna be??

Us rufty-tufty bikers seem happy enuff riding thru hundreds of miles of countryside filtering out super phosphate billowing out from farmers spreaders, caught behind sheep trucks swallowing  their aromatic trails, marveling at the sights and smells of burn-backs and bushfires, the sickly sweet whiffs on the wind of roadkill rotting roos wrinkling our noses, grain harvesters, hay baling, wild pollen laden eucalyptus bushland, smacking into stinging fly’s and bees, or dodging lazy crows at 100mph and inhaling ancient dusty sky trails of legendary dead dingo dongers from Arnhem Land... only to pull into some favourite Quinnie for a greasy burger, long-awaited cold pint and a lung filling fag!

We’re not bothered whacking sodden great big filters over our snoz’s so I should think our pussy little bikes are damn lucky!

Why are we happy to concede that factories do cut costs by installing lesser quality shocks, forks etc., than what’s best available then violently knee jerk react that their filtration choices are quality driven and not cheap price determined?

Dogma be damned.

 

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1 hour ago, ScuRoo said:

Jeezus... just how clean do you wanna be??

Us rufty-tufty bikers seem happy enuff riding thru hundreds of miles of countryside filtering out super phosphate billowing out from farmers spreaders, caught behind sheep trucks swallowing  their aromatic trails, marveling at the sights and smells of burn-backs and bushfires, the sickly sweet whiffs on the wind of roadkill rotting roos wrinkling our noses, grain harvesters, hay baling, wild pollen laden eucalyptus bushland, smacking into stinging fly’s and bees, or dodging lazy crows at 100mph and inhaling ancient dusty sky trails of legendary dead dingo dongers from Arnhem Land... only to pull into some favourite Quinnie for a greasy burger, long-awaited cold pint and a lung filling fag!

We’re not bothered whacking sodden great big filters over our snoz’s so I should think our pussy little bikes are damn lucky!

Why are we happy to concede that factories do cut costs by installing lesser quality shocks, forks etc., than what’s best available then violently knee jerk react that their filtration choices are quality driven and not cheap price determined?

Dogma be damned.

 

That's 3 min 29 seconds of my life I'm never getting back.

Ciao

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I’ve spent a lifetime mending motorbikes. I have no desire to spend my retirement doing the same shit when it can easily be avoided. (Shrug.)

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What flows best? Open velocity stacks without a screen. Emphasis on "velocity."  

What produces the best power?

Different question.

What filters the best while producing the best power?

Question #3

The P08 power curve is indistinguishable from, say K&N. 1% is statistically identical. The filtration, if true, seems to be substantially better - but is that micron size of particle what we are most concerned about? And, does it do better on smaller particles? More questions than answers at this point.

Aldous Huxley ended Brave New World with the sentence: "You pays your money and you takes your choice."  

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6 hours ago, po18guy said:

What flows best? Open velocity stacks without a screen. Emphasis on "velocity."  

What produces the best power?

Different question.

What filters the best while producing the best power?

Question #3.....

Thank you for making these distinctions.

I had thought it was a simple idea of enabling more air flow to boost power. I’m learning again from this place! Thanks for all of the great info and breaking these things down.

Cheers!

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Search here and you'll find a thread talking about punching there teardrop hole into the top of the airbox.  The PO did that to my bike.  The bike seems to run pretty good for a Guzzi.

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13 hours ago, po18guy said:

What flows best? Open velocity stacks without a screen. Emphasis on "velocity."  

What produces the best power?

Different question.

What filters the best while producing the best power?

Question #3

The P08 power curve is indistinguishable from, say K&N. 1% is statistically identical. The filtration, if true, seems to be substantially better - but is that micron size of particle what we are most concerned about? And, does it do better on smaller particles? More questions than answers at this point.

Aldous Huxley ended Brave New World with the sentence: "You pays your money and you takes your choice."  

The terminology is too broad and need defining to provide an informed answer. What is "best power" ? peak power? best power curve? engine installed in the bike? engine alone on a test bench? 

Filters by nature are restrictors which by definition means they restrict airflow. if you end up with a better power curve with the filter it means there is a fuel mapping issue and the restriction is assisting in minimising that. If you get no net loss in peak power (after optimised tuning) with a filter then it means that the intake systems flow limiting restriction is downstream somewhere like the throttle body, port shape or size or valve size.

If you are after pure peak power and best power curve then an unfiltered airbox with an effective atmospheric delivery system devoid of size and shape restrictions dictated by limitations of the available space will be best.After that its all compromise.

Ciao    

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7 hours ago, LowRyter said:

Search here and you'll find a thread talking about punching there teardrop hole into the top of the airbox.  The PO did that to my bike.  The bike seems to run pretty good for a Guzzi.

That, along with Docc's use of beer bottles to add bell-shapes to the airbox top suggest that the main restriction on the V11 is getting air to filter - not the filter itself. I think that just ditching the rubber snorkels from the airbox top might allow a bit more air in. The search for the correct shape beer bottle provides intrinsic motivation.

On the theme of airbox mods... I just put a whole new airbox and an enormous pod filter on my 7.3L Turbo-Diesel F250. The new airbox draws in fresh air from the stock intake piece (which opens in front the radiator for cool air. But it also has a huge hole in the back of the airbox, so air intake can flow in from the other side.

I'm no intake scientist, but it seems to me that holes in the V11 airbox lid would serve a similar purpose to the one I just put in my truck, allowing air to flow directly onto the filter (and more evenly over the available surface of the filter), instead of having to travel over the filter to the back of the V11 airbox.

 

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Si intravedono sotto il serbatoio i due tubi per convogliare l'aria nell'airbox

The two pipes are visible under the tank to convey the air into the airbox.

http://archivio.animaguzzista.com/page_builder.php?fileindex=saloni_eventi/C_I_Naked_2002/C_I_Naked_2002_index.txt&filebody=saloni_eventi/C_I_Naked_2002/naked_gara1/Naked_gara1_body.html

D48C14F7-A694-4CB5-93FB-912CE9617BF8.jpeg

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4 hours ago, ScuRoo said:

Si intravedono sotto il serbatoio i due tubi per convogliare l'aria nell'airbox

The two pipes are visible under the tank to convey the air into the airbox.

http://archivio.animaguzzista.com/page_builder.php?fileindex=saloni_eventi/C_I_Naked_2002/C_I_Naked_2002_index.txt&filebody=saloni_eventi/C_I_Naked_2002/naked_gara1/Naked_gara1_body.html

D48C14F7-A694-4CB5-93FB-912CE9617BF8.jpeg

Wouldn't want to be around the next time his wife wants to vacuum. Very,um, Utilitarian.

Ciao 

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That is almost exactly my idea - but without a corrugated tube - which causes turbulence and restriction. Cooler, slightly denser air produces a bit more power and more cognitive comfort for those of us who over think things. I'm planning  to use the smooth silicone hose for car turbo applications. The wall thickness is sufficient that it should never collapse. Also, cutting the air box right where Phil did - at the largest diameter just ahead of the box itself. After that, they neck down quite a bit. Does the air box design trace back to carbs? I haven't searched it yet, but almost think so. 

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I could tell you a tale about something similar.

There was a mouth breather involved.

His bike ran like a pile of damp fecal matter but he reckoned it was great because the 'Expert' responsible for both the mod and the tune said within earshot of me that "You set up fuel injection just like carbs. Just use the rod to balance the throttlebodies at idle and turn the air bleeds out 1&1/2 turns and it'll be sweet!" He'd also installed some sort of pool hose to the airbox spigots to "Get the cold air in."

This isn't just my world. Sadly it's yours as well unless you actually know how to tune your own bike.

 

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