New airbox snorkel mod

[tony.mon]

Here's my latest mod for the airbox:

I was talking to Yeti about this yesterday, and had been playing around with the snorkel last weekend.

If you look at the snorkel itself it can be enlarged by removing the foam inside and using the extra little rectangular section where the foam sits.
This will give a larger cross-sectional area for air to flow through, unfortunately the extra section doesn't extend all the way to the inlet, also doesn't extend into the airbox either.
But this can be fixed:

Firstly, scrape out the foam, using a knife or screwdriver.

Cut the open end of the snorkel (the lower, intake end) back to the point where the rectangular section is exposed.

Now at the top end, where it joins the airbox, the rectangular section finishes short, and so you'll need to cut a section out of the snorkel and a corresponding section out of the airbox so that the extra rectangular section can be extended into the box itself.

So either use a spare snorkel to chop out a section to glue/bond onto the airbox, and make a clean internal surface for the air to flow past.
Doesn't matter what it looks like externally, as it can't be seen once the tank's on.

I'd suggest that you leave the vertical divider in place; it adds stiffness but also calms the air flowing into the box.

Basically this mod increases the cross-sectional area of the snorkel, allowing more air to flow.
I wanted to achieve this because when you measure the cross-section area of the intake trumpets, the snorkel are is smaller, and so that's where the most restrictive point is.

Caveat:
Can't tell you if it shows gains on the dyno, or how it will work on your own bike; on mine it feels good, so it's staying. But I have a very modded airbox already, so this may not work well on more standard bikes.
Probably best to play with a spare airbox and see what it does, rather than chop up your only one, and find that it makes things worse.
Lastly, sometimes a restriction is deliberate, and speeds up airflow for a reason. We already know that simply removing the snorkel is ineffective, for this reason, mostly.
But if you have a spare box, and don't mind chopping it about, why not give it a try?

Comments welcome....

[lloydie]

Some pics would be very helpful
Please tony

[tony.mon]

Already installed, I'm afraid.

If you have a snorkel in your hand as you read this it should make sense.
But I'll go and chop up another one, and get some shots.

[lloydie]

I hope to get 2 spare airboxes next week
To gut out and play with .
I know when we played around with it on the dyno every thing we tried made it run richer until the box was removed altogether then it ran very lean .
I'm also thinking about moving the k&n filter element to the front and just behind the inlet snorkel so it would stand virtual .
With that done it would free up the space above the stacks .
This should help better air flow around and into the stacks .
I don't know if it will work or not .
And I will have x2 snorkels to mod as you have
Thanks for the information tony
And the wright up

[tony.mon]

Unbutchered:


See the raised rectangular section, on the outside radius?
If you look closely, you can see that it stops short both ends.

Looking down the intake end, once cut back a little, it looks like this:


Sideways on you can see how it was cut back to reveal the rectangular extra bit:


Now the more difficult bit. You can see where the extra section stops short of the airbox entry point:


So this needs to be cut out:


When assembled into the lid, it leaves a gap:


But we also need to modify the lid itself:



Because the section was cut out, the snorkel won't stay in place at the top, so it needs two small self-tappers to hold it in the correct place.
You can use countersunk ones, but they are pulled down into the rubber and so I used button heads:


Then I used a flat strip of aluminium to bridge the gap.
A sideways shot:


And one from above:


This was glued into place with Araldite, which sealed around all of the edges. I used a scrap piece of aluminium I had laying around, it's a bit scratched but cannot be seen once fitted.
The other possible solution would be to cut a section from yet another snorkel and glue that into the place; it will be the correct profile and give a better internal finish.

Once finished, from the inside it looks like this:


But I'll probably araldite a little section of plastic in each side to make it a smooth internal surface once the Araldite has hardened.

Then install, and see what you think...

[mik_str]

My snorkel is modded, albeit in a different manner. LIke you, I removed the foam. However, I used some black silicone to smooth out the ridge/step at the end. I also cut out the divider then went to town with a dremel and removed as much material as I could (snorkel walls are fairly thick). While I haven't calculated the improvement, it is quite significant in terms of area. No adverse effects and the engine definitely breaths better.

That being said, I have mondered about trying extending the said rectangular section. It may just be time..... lol

[lloydie]

thanks again tony i will be giving this a go

[KarlosVTR]

i'd be interested to know the calculations for the improvement tony.

i'd also be interested to see inside a genuine revolution racing airbox to see the modifications done there.

[tony.mon]

My snorkel is modded, albeit in a different manner. LIke you, I removed the foam. However, I used some black silicone to smooth out the ridge/step at the end. I also cut out the divider

That was exactly what I did, #1 attempt, currently on the bike.

Funny how various different owners can come up with the same ideas....

I think the method I used today is the simplest way to add flow area, but I guess thinning the walls may have a small additional contribution.
Although to add more if needed, I was going to chop two snorkels and glue them together to make one with added height.
But there's not much more room available between the frame rails, so decided to use the method shown here instead.

[mik_str]

Further to some comments made some time back by a chap on the Superhawk forum, I also drilled on 1" hole per side in the lid (just past the part of the lid that you can see under the tank). I did a straight swap from an unmolested lid to this one a few years back and saw an improvement of (going from memory here) of @ 2.5 lb-ft and 3 bhp on the dyno so it does work..... Also, while it seems silly, you'd be very surprised at just how much you can increase the area by thinning the walls. Looking at a stock snorkel it seems almost like a waste of time but when I put it and my modded snorkel side by side the difference is staggering (some tof this may be partially optical illusion though as I also sliced the intake side at an angle to facilite air entry...... ) Anyhow, dyno doesn't lie......

[tony.mon]

Further to some comments made some time back by a chap on the Superhawk forum, I also drilled on 1" hole per side in the lid (just past the part of the lid that you can see under the tank). I did a straight swap from an unmolested lid to this one a few years back and saw an improvement of (going from memory here) of @ 2.5 lb-ft and 3 bhp on the dyno so it does work.....

OK, I'll try it and report back- prob next weekend.
I have a good selection of spare airbox components, don't mind sacrificing one for the cause.

[benny hedges]

Firstly, scrape out the foam,..

what foam lol!

was none in either of mine

all i done to mine was cut the centre divider out and it improved a bogging spot at full throttle when i was running 210/215 mains

[AMCQ46]

Good stuff there tony, might copy some of that

[Vtrkidda]

Cant you just run a seperate cold feed pipe along side this snorkle thing
using a bit of flexi pipe with a air intake to the front of the bike ,like a cold air feed kit for a car

It Must do the same job after all your just putting more air into the box

Im not on about a big masive pipe just a smaller air feed thingy majig

[tony.mon]

Cant you just run a seperate cold feed pipe along side this snorkle thing
using a bit of flexi pipe with a air intake to the front of the bike ,like a cold air feed kit for a car

It Must do the same job after all your just putting more air into the box

Im not on about a big masive pipe just a smaller air feed thingy majig

Give it a try....
How are you going to connect it to the snorkel?
How are you going to route it?