Who has made custom airboxes?

[99LRDblaster]

I'm looking up some ideas on making custom airboxes and have 2 initial designs in mind. I see a lot of people running CFM airboxes and they look good and I like the design, but I'm a perfectionist. I'm looking for something with more of a straight intake since I have to make a new intake manifold for my larger carb anyways so I will either set it straight or straighter on the manifold. Then I will decrease the distance between my enclosed clamp on filter and the carb....not too difficult to do, but I want to leave a large amount of space for filtered air.....this is the quite difficult part. Not a whole lot of room to work with as well.

At any rate, I'm interested in seeing everybody's custom airbox designs, the science behind it in function, what mods you had to do to accomplish the airbox and/or air flow design you customized in past or present endeavors. I think it's good to brainstorm and build on from other's work. I:I

 

[Awk08]

79bronco is the only one i know of that completed this task
the problem i see with trying to straight shot it is the inlet to the box has to be in the center for a pod filter to connect, unless you are gonna use an k&n style flat auto filter as the lid to the whole thing, then that tubes entrance to the box wont matter

 

[79 bronco]

There is not a lot of room to get by the shock and to keep it straight, Look at my 1st pic, but the farther back you put the airbox the less of a angle you will have to run..

 

[99LRDblaster]

79bronco is the only one i know of that completed this task
the problem i see with trying to straight shot it is the inlet to the box has to be in the center for a pod filter to connect, unless you are gonna use an k&n style flat auto filter as the lid to the whole thing, then that tubes entrance to the box wont matter

A straight inlet isn't a big issue if I am following what you are saying. I think the bigger issue going STRAIGHT out is you can only go so far(including filter) until you run into the rear shock and the rear shock's full sprung area it is displaced into when it is bottomed out. This is one design I have in mind, but it's actually harder with the shock in the way since by the time you put in a bigger carb and clamp on filter, you are already by the shock.....this is where I might have to get ultra creative.

My other idea was making the airbox closer and straighter, but not completely straight. Not my blaster but an idea of what I'm thinking about doing with the only downside being:
1: It's still not completely straight, but straighter
2: It is not in the center of the quad, so it could VERY SLIGHTLY affect the left/right balance of the quad in the air, but using lightweight materials, I find this to be almost insignificant in my opinion.

Behind the frame is where there is a 40ish degree bend to run along the frame. Instead of dealing with that bend, I would rather just run this straight into an airbox mounted to the side of the frame where the frame support with holes is located. The rear shock is a big enemy here unless you mount it past the shock. The 30ish bend from the stock manifold would be reduced down to 20ish degrees bend when I make the intake manifold straighter than the stock one yet still allow enough of a bend to get around the 450R shock I'm putting on. The clamp on itself won't fit straight on.....but UNI's 15 degree bend clamp ons will. Then slap an Outerwears sheet on on the top. Just a rough idea.....the only reason I haven't started on it is because I have a 450R shock with a rezzie to install yet, and some other things of more importance before I start on this.

 

[Awk08]

if your worried about the straight shot of the tube being a greater flow issue, i wouldnt,
guaranteed the cfm box and it's angled tube can flow way more than needed by even the biggest carb on these bikes, the displacement and crankcase volume aren't great enuf to warrant all this work for flow that isnt needed

 

[3 Wh33l3r Rid3r]

if your worried about the straight shot of the tube being a greater flow issue, i wouldnt,
guaranteed the cfm box and it's angled tube can flow way more than needed by even the biggest carb on these bikes, the displacement and crankcase volume aren't great enuf to warrant all this work for flow that isnt needed

X2 i dont think u can get that tube much straighter with the shock there to see any difference than you would with the angles in a cfm box.

 

[sicivicdude]

Mine's not as pretty as bronco's but works basically the same way. I left the filter tilted to take care of one of the bends.

Like awk said, I wouldn't worry about the CFM box's bends, it can flow more than the engine can take in.

 

[99LRDblaster]

if your worried about the straight shot of the tube being a greater flow issue, i wouldnt,
guaranteed the cfm box and it's angled tube can flow way more than needed by even the biggest carb on these bikes, the displacement and crankcase volume aren't great enuf to warrant all this work for flow that isnt needed

The CFM box is perfectly fine, but I don't feel like paying all the money for it. I just wanted more of a straight shot merely because the air flow velocity can be improved at higher RPMs with a straight tube instead of an angled tube. Technically most high revving 4 stroke engines at least require 20 times the volume of air as the displacement area of the engine. F1 engines are extreme examples of this. While 2 strokes utilize displacement and crankcase volume, a similar principle applies while drawing from a vacuum through a carb. At 9000ish RPMs you are drawing in ridiculous amounts of air through the carb and it's sucking it all through an somewhat angled straw from a longer distance. I want to use a balancer tube, but make it straight/straighter as I've always found the flaw of the angled intake manifold to be rather silly on Yamaha's part as the vacuum pulls unevenly into the reed cage as the air flows.

It's rather semantical and the performance gains between the two are most likely minimal/insignificant, but like I said....I'm a perfectionist for function. I:I

 

[79 bronco]

The 1st pic is the CFM airbox, the 2nd pic is a SMS airbox..I like the SMS box better because less angles on the tube, like mine and sicivicdude air box, and the filter is angled to fit.. The CFM box has two sharp angles to center the filter in the box so it will fit in the box straight...

 

[Kgibson]

This s the best airbox

 

[3 Wh33l3r Rid3r]

The CFM box is perfectly fine, but I don't feel like paying all the money for it. I just wanted more of a straight shot merely because the air flow velocity can be improved at higher RPMs with a straight tube instead of an angled tube. Technically most high revving 4 stroke engines at least require 20 times the volume of air as the displacement area of the engine. F1 engines are extreme examples of this. While 2 strokes utilize displacement and crankcase volume, a similar principle applies while drawing from a vacuum through a carb. At 9000ish RPMs you are drawing in ridiculous amounts of air through the carb and it's sucking it all through an somewhat angled straw from a longer distance. I want to use a balancer tube, but make it straight/straighter as I've always found the flaw of the angled intake manifold to be rather silly on Yamaha's part as the vacuum pulls unevenly into the reed cage as the air flows.

It's rather semantical and the performance gains between the two are most likely minimal/insignificant, but like I said....I'm a perfectionist for function. I:I

U can get the cfm for 75 bucks new off ebay

 

[99LRDblaster]

After a second look, I think I'm going to try a third way and that's running a 2.25 silicone pipe straight back just left(viewing from behind) of the stock airbox and running a clamp on. Kind of hard to describe, but this will make the filter element about 6 inches closer while allowing me to still use a straight shot back to the carb.

Special thanks to the member that recommended this site for the silicone pipes and fittings as they are really nice and can be utilized well.
Intake Pipe Reducer

 

[Whitty21]

There is not a lot of room to get by the shock and to keep it straight, Look at my 1st pic, but the farther back you put the airbox the less of a angle you will have to run..

ever considered making them to sell?

 

[Awk08]

i believe i suggested siliconintakes.com, i do every chance i get, i luv their stuff!!!!!

and gibby did you get that box for the trade ???? i was pushin the dude to trade ya, he didnt need that

 

[blasterdemon7]

Great link awk. They have some very useful items.

 

[99LRDblaster]

Mine's not as pretty as bronco's but works basically the same way. I left the filter tilted to take care of one of the bends.

Like awk said, I wouldn't worry about the CFM box's bends, it can flow more than the engine can take in.

What diameter pipe did you use and what size clamp on is that?

 

[sicivicdude]

It's 2" exhaust pipe with ends up being like 2 1/4" OD and a matching Uni clamp on filter.

The Uni was something I had laying on the shelf off something else so I don't know the part number but I think it's a 2 1/4" clamp on.

 

[99LRDblaster]

It's 2" exhaust pipe with ends up being like 2 1/4" OD and a matching Uni clamp on filter.

The Uni was something I had laying on the shelf off something else so I don't know the part number but I think it's a 2 1/4" clamp on.

Out of curiosity what is the diameter and length of that Uni Filter? I think I have my idea in mind. The 2.25" will work with my 35PWK, but I might opt for a 2.5" simply for volumetric efficiency as I'm ROUGHLY calculating I'll be needing somewhere between 250-300cfm of airflow.