Size of air box. Need help

[aka1004]

I found couple of suitable replacement air box but need little help from people who know more about these stuff.
If there is same amount of air coming in from outside the panels thru 3 or 4" tube, depending on what I could squeeze in, would a larger air box be more beneficial?
It's either 6x6x4" or 8x8x4".
Stock stack will be cut and retained with oiled foam air filter over them.
I think either size would fit but was wondering if larger box/larger volume of air already in the box before air is forced in will be better than smaller box.

Thank you in advance.

 

[BLUEKNIGHT911]

AIR BOX

IMHO, the amount of air in the box makes no difference unless it's almost zero......but the temperature might.....Mike....:thumbup:

 

[NancysToy]

The size and shape of the airbox, as well as the airbox intake size and the size and shape of the throttle intakes are engineered for several purposes, including noise reduction, straightening the airflow, and allowing the right amount of airflow. Fiddling with any of the sizes or shapes carries a risk. You could end up either better r worse, or it may not matter. With the lack of engineering calculations, flow tests, and modeling software, you can only experiment to see what works and what doesn't. It ain't as simple as it seems!

 

[gypsy_100]

It ain't as simple as it seems!

Absolutely. The factory engineering details in areas like this are substantial. The odds of your getting it right are about zero. Unless you've got the bike on a dynamometer and can evaluate various sizes and shapes throughout the entire rpm range. Even then, the best you can hope for is to change the compromises. More top-end, less low-end, maybe (or maybe not) some improvement overall in exchange for more noise but only a dyno will tell you for sure.

 

[fastfraser]

I think FarmBoy made something that looked pretty darn good, but had to pull it off because the way it made the Spyder run .:dontknow:

 

[AMTJIM]

If it's not some personal secret squirrel ideas you wish to keep skunk works confidential, would you share what you found via pic or link?
Farmboy's mod was pretty good looking, very possibly would have worked with a few more simple mods, but I think it may have been to hidden away and may have simply been starved for air. With the filter in a plenum and a ram air tube from the right frunk vent to plenum could have been it. Or it just may be that the PVC diameter is too restrictive and doesn't have the volume it needs, it would need to be charged beyond ram air to work, looks like some fun tinkering.

 

[aka1004]

If it's not some personal secret squirrel ideas you wish to keep skunk works confidential, would you share what you found via pic or link?

I left my phone in my truck when I went in home depot
It was just Plastic waterproof electric junction box in sizes below which should acoomodate the stack and hose inlet. I think it's heavy enough to withstand the heat and fit under the frame.

 

[AMTJIM]

Search that! Somebody on here did use some electrical boxes to make an intake...forgot about that one. I think they also made some step x step photos.

 

[aka1004]

I walked aisle by aisle and this caught my eye. It has lid on top with sealing gasket so I can cut holes to match the stack, cut hole on side for air intake and secure on to throttle body than screw the lid back on. It should be air tight and easy to access air filter inside for cleaning. I still need a trip to summit racing store in so. Cal for air scoop. I am thinking amount of air thru the hole on that front scoop is not enough. It's pretty small plus partially blocked by led light housing behind the spyderpop's grill.

 

[boborgera]

Any one wonder why BRP designed the air box the way they did, ?
Contrary to popular belief they didn't do it just to annoy people.

 

[aka1004]

Wasn't brp more concerned with EPA, MPG than performance?
Why 1000's of Ryder's bought aftermarket filters, muffler and fuel mod, remove evap canister and install oil catch can?
Why are there numerous aftermarket mods?
Because I am perfectly fine with riding position of rs, does that make all comfort mods unnecessary crap?
Why ryders spend 1000's for paint on new and nicely painted panels?
Why the other brand of tires?
Why the other brand of motorcycle, completely?

 

[Campverdefela]

Wasn't brp more concerned with EPA, MPG than performance?
Why 1000's of Ryder's bought aftermarket filters, muffler and fuel mod, remove evap canister and install oil catch can?
Why are there numerous aftermarket mods?
Because I am perfectly fine with riding position of rs, does that make all comfort mods unnecessary crap?
Why ryders spend 1000's for paint on new and nicely painted panels?
Why the other brand of tires?
Why the other brand of motorcycle, completely?

BECAUSE WE CAN!!!!!!

 

[Firefly]

Here's what I've been running for the last 20,000 miles or so:

http://www.spyderlovers.com/forums/showthread.php?19296-Cheesy-airbox-2-0&highlight=intake

I have not noticed any difference in performance compared to running the Evoluzione Race Intake system.

Been meaning to do something more permanent, might look into the plastic box idea sometime, but for now I'm happy with how mine works.

 

[bcoulter19]

Isn't juice box a different type of air box and if so what makes it so good. I have seen a lot of talk on here about it.

 

[Firefly]

Isn't juice box a different type of air box and if so what makes it so good. I have seen a lot of talk on here about it.

No, a Juice Box is simply a small electronic device that can change how your fuel injectors work. Juice Box is a brand name.... just like Power Commander makes a similar type unit.

 

[Rayelljay]

With respect,
Assuming that each inlet is 1 1/2" diameter, to run a setup like Fireflie's I would have to make some alterations:
If you are going to run each inlet from a larger sized manifold, we must consider equal flow areas. To get equal flow areas, the area of the manifold to which each separate inlet is connected must be twice the area of each individual inlet.
Two 1 1/2" inlets equate to a 2 1/2" manifold.
Working out from the throttle body connection you are using a 1 1/2" elbow to go from vertical to horizontal and one more from horizontal to vertical...this adds quite appreciably to the pressure drop through the system sufficient to consider the increase of one pipe size after the first elbow out of the throttle body to 2".
The second elbow should be turned 45 deg so that the connection to the 2 1/2" manifold should be made with a 45 deg. lateral fitting. After the connection of both to the manifold, you would be wise to increase the manifold diameter to 3" for connection to the filter. I don't know whether you have enough room to do all that.
But there are other considerations, too.
The plenum/airbox is designed to mitigate as far as practical the high frequency pressure pulses generated by the process of charging each cylinder through the inlet valves. You can get a pressure wave that will tend to inhibit full charging of the cylinder kinda like scavenging on a two stroke engine...you remember what competition pipes looked like on the early racing bikes.
The shape of the airbox has a lot to do with the reflection and mitigation of those pressure waves, so a rectangular air box may not be appropriate. The volumetric capacity lowers the velocity of the incoming air charge and minimises the system pressure drop.
I learned all this from years of piping up multiple compressors in industrial applications and the engineering of steam manifolds in power plants.
Honestly, I'd leave the stock system as it is until BRP comes out with a supercharger upgrade to reduce the inlet tract pressure drop.

 

[aka1004]

Would a direct feed into the stacks thru a 3-4" main tube splitted to 2" than a 90* reducer into the stacks be a better alternative to a square or rectangular air box?

With respect,
Assuming that each inlet is 1 1/2" diameter, to run a setup like Fireflie's I would have to make some alterations:
If you are going to run each inlet from a larger sized manifold, we must consider equal flow areas. To get equal flow areas, the area of the manifold to which each separate inlet is connected must be twice the area of each individual inlet.
Two 1 1/2" inlets equate to a 2 1/2" manifold.
Working out from the throttle body connection you are using a 1 1/2" elbow to go from vertical to horizontal and one more from horizontal to vertical...this adds quite appreciably to the pressure drop through the system sufficient to consider the increase of one pipe size after the first elbow out of the throttle body to 2".
The second elbow should be turned 45 deg so that the connection to the 2 1/2" manifold should be made with a 45 deg. lateral fitting. After the connection of both to the manifold, you would be wise to increase the manifold diameter to 3" for connection to the filter. I don't know whether you have enough room to do all that.
But there are other considerations, too.
The plenum/airbox is designed to mitigate as far as practical the high frequency pressure pulses generated by the process of charging each cylinder through the inlet valves. You can get a pressure wave that will tend to inhibit full charging of the cylinder kinda like scavenging on a two stroke engine...you remember what competition pipes looked like on the early racing bikes.
The shape of the airbox has a lot to do with the reflection and mitigation of those pressure waves, so a rectangular air box may not be appropriate. The volumetric capacity lowers the velocity of the incoming air charge and minimises the system pressure drop.
I learned all this from years of piping up multiple compressors in industrial applications and the engineering of steam manifolds in power plants.
Honestly, I'd leave the stock system as it is until BRP comes out with a supercharger upgrade to reduce the inlet tract pressure drop.

 

[bcoulter19]

Isn't juice box a different type of air box and if so what makes it so good. I have seen a lot of talk on here about it.

Thank you, I have just had my spyder for about 9 months and had seen that several times and did not know what it was.

 

[Rayelljay]

Would a direct feed into the stacks thru a 3-4" main tube splitted to 2" than a 90* reducer into the stacks be a better alternative to a square or rectangular air box?

Honestly, I couldn't tell you but it does sound mechanically viable.
But, as I said in my epistle, the pressure pulses in the inlet tract need to be addressed and that is why I would be loth to tamper with the original equipment.
My offering was meant to stimulate further thought and not as a "how to do it".
You need to bear in mind that messin' with what is there from the factory may void your warranty, too.
I've seen installations of compressor inlets that had a tendency to act like organ pipes and they required inlet silencers to prevent "drumming" and excessive mechanical vibration. Granted, these installation are for equipment running at a constant RPM.
Internal combustion engine inlet design can get very complicated so I believe that the best advice I can offer is "if it ain't broke, leave it alone".