Airbox Inlet Elbow Hack

[ScuRoo]

Q: Would it be possible to effectively open up the inlet opening by just hacksawing across to the widest point of the squared off elbow?

Wouldn’t also incorporating the elbow volume actually offer a bigger total opening for airflow ingress than just reworking the round hole before the elbow?

A whopping big scoop funnelling into airbox...?

[ScuRoo]

It might also be easier cutting with a hacksaw blade than the bottle remoulding process.

Hoping the pic lines help indicate what I’m contemplating...

[footgoose]

I had similar thoughts when thinking about bell-mouthing my lid inlets. The air gets scrunched back down as it goes into the lid a few inches back. So is there any advantage to opening these up?

[Scud]

Interesting.... and what about just cutting some large circles in one or more of the four flat sides of the blocky part? At some point the filter will become the most restrictive element. (unless the "scrunchy" zone is already the smallest point.

Docc says the bell makes it sound cooler, so that's an advantage.

[red lion]

I still have the stock air box inlets that pull air into the air box from the front of the bike that are held on with hose clamps. Are there advantages to removing them and will removing them give the bike a better intake howl?

[docc]

2 hours ago, Scud said:

Interesting.... and what about just cutting some large circles in one or more of the four flat sides of the blocky part? At some point the filter will become the most restrictive element. (unless the "scrunchy" zone is already the smallest point.

Docc says the bell makes it sound cooler, so that's an advantage.

Oh, yeah! And that belled inlet in the original post look mighty familiar . . .

 

[Lucky Phil]

1 hour ago, red lion said:

I still have the stock air box inlets that pull air into the air box from the front of the bike that are held on with hose clamps. Are there advantages to removing them and will removing them give the bike a better intake howl?

Yes, more room for the fuel filter 

 

[MartyNZ]

On 9/21/2021 at 7:59 AM, ScuRoo said:

Q: Would it be possible to effectively open up the inlet opening by just hacksawing across to the widest point of the squared off elbow?

Wouldn’t also incorporating the elbow volume actually offer a bigger total opening for airflow ingress than just reworking the round hole before the elbow?

A whopping big scoop funnelling into airbox...?

I like your idea, but first, think about this:

a. the snorkels exist mainly to draw cool air from forward of the hot air rising from the engine. Cool air = dense air so better performance. Shortening the air path may hurt more than it helps if it draws in hot air.

b. The step in the intake snorkels is designed to catch and drain any water droplets from road spray & heavy rain. A coalescence trap. Cutting will remove that function. Maybe not a problem if you don't ride in rain.

c. Since you already modified the bell mouths on the two snorkels, I expect the combined airflow available will already exceed the alternating flow demands from each throttle body, so opening the snorkels up further may not help.

If you have a spare airbox cover, it would be a good experiment to try.

[Rox Lemans]

I just omitted the whole top of the airbox and put in a frame to hold in the air filter. I think it's 2 M5 screws that hold that bugger in.. 

[po18guy]

My idea, yet to be realized, is to open the snorkels about 2" in front of the box lid, then run 2.25" or 2.5" 45º bend silicone car turbo hoses down at a 45 from each, then forward as far they will go. Could top them with velocity stack screens. Dunno. 

[docc]

To me, it still seems like the worst possible approach is to attach a couple restricted, down-turned rubber snorkels to pick up the hottest air coming off the exhaust manifolds when sitting at a stop.  I still have mine. In a bag somewhere . . .

[po18guy]

The point is to keep moving! The OEM system is actually a supplemental cylinder heads cooling vacuum. Actually, along the spine up to the steering head would be ideal - except for all those thingies in the way.

[footgoose]

1 hour ago, po18guy said:

My idea, yet to be realized, is to open the snorkels about 2" in front of the box lid, then run 2.25" or 2.5" 45º bend silicone car turbo hoses down at a 45 from each, then forward as far they will go. Could top them with velocity stack screens. Dunno. 

To me, this is the only way to actually increase the amount of flow into the airbox while still using snorkels of some kind. The inlets without the rubbers are 40mm and appears to stay relatively the same into the lid tho it does oval out some. The next step up would be scud's holes in the sides or top, which is what the dirt bike tuners do sometimes. If that isn't enough take off the lid and clamp the filter down as suggested. I have ridden in rain hard enough to spray the intake with water if I'd had the lid off. I run it with the lid on and no goofy rubber tips. The stock filter is replaced with a BMC (more or less a K&N) and free flowing exhaust. She's really happy.

[po18guy]

4 minutes ago, footgoose said:

To me, this is the only way to actually increase the amount of flow into the airbox while still using snorkels of some kind. The inlets without the rubbers are 40mm and appears to stay relatively the same into the lid tho it does oval out some. The next step up would be scud's holes in the sides or top, which is what the dirt bike tuners do sometimes. If that isn't enough take off the lid and clamp the filter down as suggested. I have ridden in rain hard enough to spray the intake with water if I'd had the lid off. I run it with the lid on and no goofy rubber tips. The stock filter is replaced with a BMC (more or less a K&N) and free flowing exhaust. She's really happy.

One could also fab up a lid out of 1/4" ABS sheet with inlets sized and placed wherever desired.

[ScuRoo]

Thanks gents.

No one yelled, “Stop! Are you mad!”, so I feel this would suit me more than battling with uncooperative hardened plastics - or left with a congealed melted blowout!

My primary mission was simply to find a shortcut - which I’m encouraged from the feedback is doable & probably worthwhile. 

Now I turn to Phil A ‘s elegantly described & qualified concept to increasing airflow which  it was hypothesised the funnels were to still be a limiting factor in supplying the larger throttle bodies (50mm?) even with the additional beer bottle flaring flanges!

So... in hacksawing off what is effectively the anterior portion of the Inlet Elbow and incorporating that extra volume into the existing funnel opening above - would then these two whopping forward facing Elbow Scoops supply an ample amount of airflow into the airbox enclosure proper?

Or would a state of  inadequate cfm airflow supply to the cylinders still be present?

Ergo..., would Phil A ‘s tri-teardrop (3Drop?) lid mod be: 
• absolutely required
• harmonically beneficial
• probably superfluous 
• negatively impacted

Should both be done - or the Elbow Scoops be adequate??

I’m conscious that enough is enough - any more is likely just adding turbulence.