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has anyone tried this air filter set-up?

reddevilmedic

By reddevilmedic
in General Tech Talk

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Condor

Condor

Posted
Posted
earls ideas work! not sure about this. should measure it and find out if the box needs to be removed altogether. maybe could replace it with a smaller storage container somehow. i need something to attach my fuse blocks and tci to.

 

My big concern would be how the engine will run with the airbox off. We all know it doesn't appreciate a lot of air flow, and will this setup give enough vacuum..... I think... and I might be wrong... that the diaphragms won't work very well without venturi/airbox vacuum?? Maybe that's why they claim a 4mpg gain, but at what loss to performance??

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Condor

Condor

Posted
Posted
i would think that an increase in air and fuel would equal more power. the box would definately have to go, it seems that it gets so little air now, and i dont really think that this setup boosts the air intake by a whole lot. considerining the filters are still buried.

 

Think about it this way. There is an oval opening at the top of the carb venturi that supplies vacuum to the diaphragm causing it to pull the jet needle out of the jet and supplying fuel as needed. The greater the vacuum...the more fuel. Try taking compressed air and blowing it across the opening.. not into it... but across it and you'll see what I mean. The air stream will create a low pressure negative vacuum above the opening and the diaphragm will start to retract the needle and open the jet and supply fuel as needed. The same thing happens when cranking open the throttle and increasing manafold vacuum. Once a speed is reached the vacuum drops and the needle closes the jet to a point where it only supplies fuel needed to maintain that speed. Without that vacuum the diaphragm will not properly function as designed. That's why the Venture motor VR's run like cr@p without the lid on the air box. It needs that restriction. If anyone has a bike that is not effected, it's because they have diaphragm/carb problems.... :stirthepot:

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skydoc_17

skydoc_17

Posted
Posted

Hey Mike,

I have seen, (and Installed) more than a few of these "pod" type filters on VMAX'S and one or two Ventures here at the shop. If we realize that fuel (gas) as a liquid doesn't combust in an engine, and it is when air (oxygen) and fuel (gas) are combined (atomized) into a vapor, that creates the conditions that allow our engines to run.

Yamaha (and every other post EPA manufacturer) restrict the air flow to the engine which allows the use of much smaller fuel jets which it turn give decent gas mileage, and almost total consumption of the hydrocarbons in the fuel. (clean burn)

With the ratio of air to fuel being a constant, (which it is on our bikes, or any engine without supercharging, or turbocharging) if you add these pod filters to your VR, you will need to rejet the Carbs. BIG TIME! And I can absolutely guaranty you that your gas mileage will suffer as a result. BUT, you will see an increase in the amount of Horse Power that your V4 motor will generate. The second feature the air box provides is to "smooth out" the throttle response, by limiting the amount of air that can be drawn into the engine. Jack, to address your statement about the loss of Vacuum, each cylinder will draw the same amount of volume on the intake stroke, (1294cc divided by 4) so the amount of slider movement will be faster because of the lack of restriction.

What this means in the real world:

This bike with enlarged main jets and pod filters is going to have an increase in Horse power, the gas mileage is going to be in the mid 20's, the throttle is going to be extremely "twitchy", meaning it is going to basically have one speed, WIDE OPEN!

So if you want a bike that would make an excellent "VROD Hunter", but barely idle at a stop light, and don't mind getting 25MPG, but have the ability to cruse on the highway at 100MPH all day long, then these filters are for you. If you would like to continue to ride your VR thru town, stop at stop lights every now and then without the bike shutting off, get between 38 and 50+MPG, and have your wife/girlfriend/boyfriend still on the back when you exit the freeway,:crackup: then stick with the air box, buy the K&N filter, and call it a done deal! (This is the short version, but believe me when I say, "been there, done that") :thumbsup2:

Earl

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Condor

Condor

Posted
Posted
Hey Mike,

I have seen, (and Installed) more than a few of these "pod" type filters on VMAX'S and one or two Ventures here at the shop. If we realize that fuel (gas) as a liquid doesn't combust in an engine, and it is when air (oxygen) and fuel (gas) are combined (atomized) into a vapor, that creates the conditions that allow our engines to run.

Yamaha (and every other post EPA manufacturer) restrict the air flow to the engine which allows the use of much smaller fuel jets which it turn give decent gas mileage, and almost total consumption of the hydrocarbons in the fuel. (clean burn)

With the ratio of air to fuel being a constant, (which it is on our bikes, or any engine without supercharging, or turbocharging) if you add these pod filters to your VR, you will need to rejet the Carbs. BIG TIME! And I can absolutely guaranty you that your gas mileage will suffer as a result. BUT, you will see an increase in the amount of Horse Power that your V4 motor will generate. The second feature the air box provides is to "smooth out" the throttle response, by limiting the amount of air that can be drawn into the engine. Jack, to address your statement about the loss of Vacuum, each cylinder will draw the same amount of volume on the intake stroke, (1294cc divided by 4) so the amount of slider movement will be faster because of the lack of restriction.

What this means in the real world:

This bike with enlarged main jets and pod filters is going to have an increase in Horse power, the gas mileage is going to be in the mid 20's, the throttle is going to be extremely "twitchy", meaning it is going to basically have one speed, WIDE OPEN!

So if you want a bike that would make an excellent "VROD Hunter", but barely idle at a stop light, and don't mind getting 25MPG, but have the ability to cruse on the highway at 100MPH all day long, then these filters are for you. If you would like to continue to ride your VR thru town, stop at stop lights every now and then without the bike shutting off, get between 38 and 50+MPG, and have your wife/girlfriend/boyfriend still on the back when you exit the freeway,:crackup: then stick with the air box, buy the K&N filter, and call it a done deal! (This is the short version, but believe me when I say, "been there, done that") :thumbsup2:

Earl

 

Good info Earl. Rejetting the carbs would be the only way to keep the fuel amount adiquate for highend performance with a limited travel slide, and would give the :sign woo hoo: results you discribed. I wonder how the ebay seller can claim 4mpg increase, and still maintain highend performance?? Unless like you discribed the highend permormance is sacrificed unless rejetted. I'm getting a headache....:bang head: :big-grin-emoticon:

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mikentinamidnight

mikentinamidnight

Posted
Posted (edited)

there were four of them on my trike when i got it and it ran like crap even with the choke all the way out.

the useless dealer i bought the bike from said it had been rejetted to use them but that was just another lie from them as when i put a stock intake system on it it was like a totally new bike. all kinds of power.

(lesson learned never buy sight unseen over the phone)

i had the jets checked to make sure they were the proper ones for the stock system and they were.

so without rejetting the carbs it WILL run like garbage.

 

mike

Edited by mikentinamidnight
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Squeeze

Squeeze

Posted
Posted
Different filters but similar idea to what was on the '89 that I had with the VMAX conversion.

 

http://www.venturerider.org/forum/showpost.php?p=337024&postcount=40

 

This looks like a Dyna Stage7-Kit with the individual Filters, permanent open V-Boost and the Canister for Engine Breather.

 

If the Carbs are properly jetted, this actually Works, but i never heard of such a low Fuel Consumption. Maybe if you only lurk around at 40 mph on backroads. But if you plan on doing so, such a Stage Kit doesn't make Sense at all.

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twigg

twigg

Posted
Posted

Going down that route would require a dyno to jet the carbs correctly, unless you really know what you are doing.

 

I fitted them to my 1977 Yamaha Triple, because K&N don't make a filter for the '77. It is not without issues though. The airbox is not just a box to hold the filter, it is a tuned device that controls both the quantity of air and the speed it moves.

 

In any event .... K&N does make a filter for our bikes, and it is normally a straight swap with not jetting issues.

 

At worst, shimming the needles to allow a little more gas in the mid-range is probably all that would ever be needed. And that's an easy job

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V7Goose

V7Goose

Posted
Posted
Think about it this way. There is an oval opening at the top of the carb venturi that supplies vacuum to the diaphragm causing it to pull the jet needle out of the jet and supplying fuel as needed. The greater the vacuum...the more fuel. Try taking compressed air and blowing it across the opening.. not into it... but across it and you'll see what I mean. The air stream will create a low pressure negative vacuum above the opening and the diaphragm will start to retract the needle and open the jet and supply fuel as needed. The same thing happens when cranking open the throttle and increasing manafold vacuum. Once a speed is reached the vacuum drops and the needle closes the jet to a point where it only supplies fuel needed to maintain that speed. Without that vacuum the diaphragm will not properly function as designed. That's why the Venture motor VR's run like cr@p without the lid on the air box. It needs that restriction. If anyone has a bike that is not effected, it's because they have diaphragm/carb problems.... :stirthepot:
Just a note for anyone reading this thread and trying to learn about the intake system and carbs - this is not a correct description of how the intake system or CV carbs work - just one example, intake manifold vacuum is highest when the throttle is CLOSED, not open. Do your research to find better information.

 

But I do agree completely that changing the stock intake system is a very bad idea.

Goose

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Condor

Condor

Posted
Posted
Just a note for anyone reading this thread and trying to learn about the intake system and carbs - this is not a correct description of how the intake system or CV carbs work - just one example, intake manifold vacuum is highest when the throttle is CLOSED, not open. Do your research to find better information.

 

But I do agree completely that changing the stock intake system is a very bad idea.

Goose

 

Your right, but since I'm talking about venturi vacuum and airflow what happens when throttle's open? Venturi flow increases. If there's a restriction in the air flow supply a vacuum is created. Or maybe you have a better explaination of why these bikes run like cr@p with the air box lid off.... Doesn't take a rocket scientist... just a little common sense.

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  • 6 years later...

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