removed air horns in the hood?
- Thread starter ullose272
- Start date
I was wondering the same thing on my pro, I used to remove the air horns on the edge models. But in talking to SLP they said the air horn actually increases velocity and removing them would decrease throttle response. So I'm leaving mine in for now, but I do highly recommend the all new vforce3r reeds!
Whoops, yeah I was talking about the ones in the air box by the throttle bodies. I wasn't even aware there are air horns in the hood intake area. I would be interested in knowing if any benefits to removing those as well.
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The two lower rubber ones use a well known proven design used for the last couple hundred years that accelerates air as it passes through. Search the Venturi effect or Bernoulli's Equation... I wouldn't mess with those as they probably do a really nice job of accelerating air around that almost 90 degree turn into the throttle bodies from the air horns up above. My educated guess is that this induction system actually increases the pressure in the air box to a little bit higher pressure than the ambient outside static pressure which would be beneficial. I am really interested in the mods to those horns too, anyone having proven success with opening them up?
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Increased air velocity=decreased pressure. That's kinda how planes fly.
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Way Oversimplified icr... That may be 50% of the airbox venturi situation... what happens to the pressure available at the t-bodies when that increased velocity air is smashed into that finite space of the air box at the higher velocity?
It's not a wing....Got the airplane deal worked out thanks
Way Oversimplified icr... That may be 50% of the airbox venturi situation... what happens to the pressure available at the t-bodies when that increased velocity air is smashed into that finite space of the air box at the higher velocity?
It's not a wing....Got the airplane deal worked out thanks
The greater the restriction, the greater the velocity= less pressure. You brought up the Venturi effect, that's it in a nut shell.
I'll be honest, I'm having trouble understanding how your educated guess is that increased velocity=increased pressure while citing the Venturi effect. It seems contradictory, now I'm not the brightest spark plug in the cylinder so if you could draw me a picture id appreciate it.
Unless of course your premise is that the air flow is supersonic between the air horns and throttle bodies, then your theory is sound, but wrong.
Unless of course your premise is that the air flow is supersonic between the air horns and throttle bodies, then your theory is sound, but wrong.
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icr, After reading up on your other recent posts, your failure to address what happens to the pressure available at the t-bodies when that increased velocity air is "smashed" into that finite space of the air box at the higher velocity produced by Bernoulli's principle and the Venturi effect, and the above comments about supersonic flow in the induction system of a snowmobile, plus your request for a picture
I suspect you are just flaming away. I am really interested to hear if people are having any success with opening up the horns above the airbox.
icr, After reading up on your other recent posts, your failure to address what happens to the pressure available at the t-bodies when that increased velocity air is "smashed" into that finite space of the air box at the higher velocity produced by Bernoulli's principle and the Venturi effect, and the above comments about supersonic flow in the induction system of a snowmobile, plus your request for a picture
I am really interested to hear if people are having any success with opening up the horns above the airbox.
I removed the horns on my 11, no appreciable difference. Left them in on my 13 and 14. Here's a picture of bernoulis principle, I'm not flaming, just tired of the misinformation thrown around on this site as fact.
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geo
Well-known member
Lotsa clean air, lotsa clean fuel, lotsa clean oil.
I open up all my sleds plenums to seal them when I'm prepping a new to me sled. They are all "super leaky" just sitting there. Add the vibration and bouncing and they open up more.
Might be my bike background but I don`t want anything except clean air getting into my TB`s. Snow, belt dust, etc. are not wanted lol.
While I was there I added the SLP vent to help in deep days and took out the top horns because there was two more noise restrictions to go before the TB`s. Still no honk so I was happy.
This year I opened up the motor internally and added another Poo horn to the shelf to help because I went beyond Poo`s design for engine air needs.
The plenum horns and shelf horns are there for only one reason and that is noise (EPA). Velocity stacks (the last venturi before the TB`s which is the start of all the engine's built in "ventureez" lol) the TB`s are a different story.
There the art of maximizing air flow here has been played with since the first NA engine "lost" it's airbox because the filter was dirty and there was only 4 hrs of daylight left to get the potatoes in lol. Small changes can make big differences.
The shelf an it's horns is a tuning tool today because everyone needs to pass noise tests. Small changes can make big differences. DON'T change this unless you are ready to play with your fuel controller. This is not the days of self compensating carbs with variable venturi drawing fuel according to airflow. The simple injection system adds only the fuel that the 'putor tells it to no matter how much or little air is passing through the TB's.
Most of the "delicate" fuel #'s will be down low and part throttle positions but the "scarey" #'s will be wide open. It all depends on how "tight" Poo made that shelf.
Removing the shelf will get more airflow, maybe you can tune it for more HP too (depends if the engine needs it or not) and if you play with the velocity stacks on the TB's you might increase powerband too.
After all that work and you get it working great you will have a "honky" loud intake and burn way more fuel. Lotsa fun lol.
ICR, your diagram is correct out of the book but you forgot the vacuum on the engine side (open up the air pump and it takes away the air in the finite volume box). So more velocity in the restricted part fed by the more pressure on the "air-in" side and compounded by the vacuum's "pull" on the engine side equals more air through a smaller hole which changes the amplitude of the sound wave coming out of that noisy engine and exiting out to our already noise polluted environment.
LOL, so simple ICR. I don`t know why you don`t get it.
I open up all my sleds plenums to seal them when I'm prepping a new to me sled. They are all "super leaky" just sitting there. Add the vibration and bouncing and they open up more.
Might be my bike background but I don`t want anything except clean air getting into my TB`s. Snow, belt dust, etc. are not wanted lol.
While I was there I added the SLP vent to help in deep days and took out the top horns because there was two more noise restrictions to go before the TB`s. Still no honk so I was happy.
This year I opened up the motor internally and added another Poo horn to the shelf to help because I went beyond Poo`s design for engine air needs.
The plenum horns and shelf horns are there for only one reason and that is noise (EPA). Velocity stacks (the last venturi before the TB`s which is the start of all the engine's built in "ventureez" lol) the TB`s are a different story.
There the art of maximizing air flow here has been played with since the first NA engine "lost" it's airbox because the filter was dirty and there was only 4 hrs of daylight left to get the potatoes in lol. Small changes can make big differences.
The shelf an it's horns is a tuning tool today because everyone needs to pass noise tests. Small changes can make big differences. DON'T change this unless you are ready to play with your fuel controller. This is not the days of self compensating carbs with variable venturi drawing fuel according to airflow. The simple injection system adds only the fuel that the 'putor tells it to no matter how much or little air is passing through the TB's.
Most of the "delicate" fuel #'s will be down low and part throttle positions but the "scarey" #'s will be wide open. It all depends on how "tight" Poo made that shelf.
Removing the shelf will get more airflow, maybe you can tune it for more HP too (depends if the engine needs it or not) and if you play with the velocity stacks on the TB's you might increase powerband too.
After all that work and you get it working great you will have a "honky" loud intake and burn way more fuel. Lotsa fun lol.
ICR, your diagram is correct out of the book but you forgot the vacuum on the engine side (open up the air pump and it takes away the air in the finite volume box). So more velocity in the restricted part fed by the more pressure on the "air-in" side and compounded by the vacuum's "pull" on the engine side equals more air through a smaller hole which changes the amplitude of the sound wave coming out of that noisy engine and exiting out to our already noise polluted environment.
LOL, so simple ICR. I don`t know why you don`t get it.
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Geo's last paragraph is better put. Factoring in the pull from the engine through the lower box, what I wrote made perfect sense to me at 2am
Polaris and Arctic Cat (and possibly the others) have been using the Venturi effect for a number of years in the lower part of the airbox. I was simply saying I wouldn't mess with that.
icr to help complete the derail... it is a fact that Bernoulli's is at work in a Venturi system, which this is. http://en.wikipedia.org/wiki/Venturi_effect http://www.grc.nasa.gov/WWW/k-12/airplane/bern.html
http://hyperphysics.phy-astr.gsu.edu/hbase/pber.html
My post was hypothesizing about what happens downstream of the constriction at the T-bodies. This would be at the far left on the diagram you posted AFTER the velocity drops and pressure rises back up. I think that's what we aren't communicating well on.
No one is posting misinformation as fact.
Wouldn't it be nice to be able to know exactly which parts of these are designed for noise and emissions. There is a curiously large amount of engineering in the intake systems on these sleds.
Polaris and Arctic Cat (and possibly the others) have been using the Venturi effect for a number of years in the lower part of the airbox. I was simply saying I wouldn't mess with that.
icr to help complete the derail... it is a fact that Bernoulli's is at work in a Venturi system, which this is. http://en.wikipedia.org/wiki/Venturi_effect http://www.grc.nasa.gov/WWW/k-12/airplane/bern.html
http://hyperphysics.phy-astr.gsu.edu/hbase/pber.html
My post was hypothesizing about what happens downstream of the constriction at the T-bodies. This would be at the far left on the diagram you posted AFTER the velocity drops and pressure rises back up. I think that's what we aren't communicating well on.
No one is posting misinformation as fact.
Wouldn't it be nice to be able to know exactly which parts of these are designed for noise and emissions. There is a curiously large amount of engineering in the intake systems on these sleds.
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At some point doesn't more air present a problem with becoming too lean?
I removed my hood air horns because I have a Silber turbo and the intake requires more air. The little tabs on the air horns are very brittle. I found that heating them up with a heat gun made them more pliable.
I removed my hood air horns because I have a Silber turbo and the intake requires more air. The little tabs on the air horns are very brittle. I found that heating them up with a heat gun made them more pliable.
The reason that the venturi tubes were in the Edges, according to trained Polaris sales personnel, was the tubes create a harmonic vibration of the intake air in the chamber between the venturi tube and the reeds, that supposedly increases performance. Of course Polaris also said that the Edges weighed less than 500 lbs dry. And mine weighed 525 lbs dry.
