Airbox snorkel

[roxrny]

I've only seen one tuner look at the snorkel issue WHILE CONSIDERING THE EFFECTS OF THE BAFFLE AS WELL (the part of the snorkel assembly that goes inside the filter) - it is this part that is the problem as it significantly inhibits flow.  
So when we remove the snorkel/baffle and are seeing better performance, we're really seeing the benefits of removing the baffle, not the exterior snorkel section. Consider that there is a better solution where one removes the baffle and leaves the external snorkel. I wish the other tuners would look at this aspect as well instead of simply stating to remove the entire snorkel.
 
I'm an engineer and have done quite a bit of design with flow, and shaping the flow is very important to overall flowrate, both in the intake and the exhaust side of any orifice. The exterior snorkel part shapes the flow better than the sharp-edge of the filter/cover, so you are actually getting better flow with it in but with the baffle removed.

The Air box cover by DNA has a 3/8" radius bevel on it. Not a sharp edge. Not sure if that makes a difference. 

[Guest ChicagoAJ]

I've only seen one tuner look at the snorkel issue WHILE CONSIDERING THE EFFECTS OF THE BAFFLE AS WELL (the part of the snorkel assembly that goes inside the filter) - it is this part that is the problem as it significantly inhibits flow.  
So when we remove the snorkel/baffle and are seeing better performance, we're really seeing the benefits of removing the baffle, not the exterior snorkel section. Consider that there is a better solution where one removes the baffle and leaves the external snorkel. I wish the other tuners would look at this aspect as well instead of simply stating to remove the entire snorkel.
 
I'm an engineer and have done quite a bit of design with flow, and shaping the flow is very important to overall flowrate, both in the intake and the exhaust side of any orifice. The exterior snorkel part shapes the flow better than the sharp-edge of the filter/cover, so you are actually getting better flow with it in but with the baffle removed.

Only if the snorkel is designed properly. I've seen reports that simply by removing the entire snorkel the bike gains power on a dyno versus when the bike is tested with the snorkel in. This means the snorkel doesn't do anything for flow except bottleneck it.  

[sansnombre]

You're missing the point - when you remove the entire snorkel, you're removing the bottleneck as well => the internal baffle part that's inside the filter. So yes, it's going to increase horses. But look at the same runs with the snorkel in and the baffle removed and there is your third point, and in this case, it's better than the snorkel/baffle fully out. There are dyno runs to support this (Hord), so on this bike, the snorkel is apparently designed well and it behooves you to keep it in. I think it goes without saying that a poorly designed snorkel is going to decrease flow relative to it being removed.
 
@roxrny
Yes, the slight radius of the DNA cover is helpful but not as well as a fully contoured entrance. Better than not having it, that's for sure.
 
Another issue, is that for WFO, maybe taking the snorkel out is the way to go, because it's max flow. But part of the equation is the dynamics of the flow from idle to redline. And this is where the tuning comes into play - actually having a tuned restriction can help low and midrange at the expense of WFO. Depends what you're doing and what you're looking for.

[Guest ChicagoAJ]

That's where the 2WDW flash comes in. It's tuned on the snorkel removed.

[sansnombre]

Exactly.
 
And that's my original point - I wish 2WDW, PCV, and the EJK boys would take a look at the output with the baffle removed and the snorkel in place. A third tuner says this is the way to go, so I'd like to see other tuners at least take a look at that configuration and if it's better, tune their products to that setup.
 
My hunch says it's likely a better config so I tend to believe the third tuner, but to set up your ride to that config, you're on your own, so it sucks. If 2WDW would tweak their most excellent flash to this, it'd be that much sweeter.
 
Cheers.

[hordboy]

I didn't spend a huge amount of time testing all the various combos. The differences aren't that great in the grand scheme of things, open vs. cut snorkel. I like the idea somebody posted of the DNA top plate with the foam MWR filter. That might be worth testing. Usually a foam filter will "act" more like open atmosphere (or less volume than an equivalent K&N type filter) when it comes to matters of airbox volume. Just my two cents.

[gregjet]

Foam filters almost always had a greater restriction than paper and fabric ones. The reason they are so good on a dirt bike is they are fantastic and repelling water when oiled. Unfortunately they also eventually (most) turn to a sticky powder when they degrade. That includes K&N foams.
Almost all aftermarket flow better than the OEM ones from the stuff I have seen. Particularly K&n, BMC and DNA. DNA filters usually try and increase the actual filter area where they can fit it into the stock shape.
From Gordon Blair's work I have seen 3/8" radius is pretty much a sharp edge.
Flow is almost NEVER as simple as it seems. ( thank you chaos). Both the up stream side AND the downstream side matter. Cutting the bottom of the snorkel off MAY adversly effect the stream or it MAY help. That depends on how the 3D stream(s) are through the filter and the airbox.
The upstream side also has a boat load of stuff influencing the flow inwards. The only way to actually know what is going on ( short of a supercomputer) is to empirically test it.
Making the hole bigger will only effect the overall flow until max flow occurs, which may or may not be limited by the available hole size. Flow through a particular hole size is not independent of the 3d shape of the hole. You can design a smaller cross-section that will flow way more than a bigger hole in a plate.
I dynoed the bike with stock airbox and DNA filter ,with and without the snorkel ( simply removing it), and got no significant change in HP anywhere in the rev range. I didn't redyno after I made the smoothed inlet. Note I have a re-flashed ECU with the "O2" sensor attached so fuelling will not be an issue.
A bigger filter surface area  has been shown to pass more air and  produce more power ( re: hordboy)
 

[Guest 2wheeler]

This has got me thinking. I recently had my bike flashed by 2WDW for stock exhaust and snorkel out. I really don't like the intake sound. The plan is to experiment with removing the baffle portion of the snorkel. This of course will not be quite the same airflow as the snorkel being completely removed. The thought that came up is to what degree adding a K&N or a DNA would offset the airflow loss from putting the modified snorkel back in as they are both suppose to have better airflow than the OEM air filter.
 
The joy of experimentation!
 
Side question for everyone - does the snorkel face forward or backward? I don't remember exactly but I think it faced forward on the 2016 US model, but I thought I have heard that it varies especially between US and EU/other.
 

[norcal616]

The problem is an ineffective airbox design.. the intake tubes are practically right up against the air filter... to me and many others think the snorkel is a glorified sound cancelation device so ppl don't complain about " noises"
 
The snorkel faces forward

[Guest Ralph]

I thought the UK one like mine pointed forward and the US one back but can't be bothered
looking, what I do know is that mine as a ECU controlled flap moved by the silver vacuum
actuator in the pic that bypasses to snorkel most of the time,
 
http://i235.photobucket.com/albums/ee111/G7ied/DSCF5562_zpsed7bde96.jpg
 
 
Must be more to it than just noise as it's a lot of trouble to go to when just 
sticking a snorkel on as in the US one would pass the noise test.

[sansnombre]

I'm pretty sure it's facing backward, sucking in cooler (relatively), non-engine heated air.

[noob]

So I have read through the thread. Is there any benefit of my removing my snorkel on a stock bike? no tune or exhaust on. Or how about replacing with DNA filter and cover - is this going to hurt performance if I don't have a tune yet?

[gregjet]

A DNA filter will give you a little extra flow at max load end of the revs and at min end. I put them in at first filter change mainly for ability to clean and reuse. The stock paper filters here are so expensive you only get a cheaper filter for 2 changes .
Not convinced about the DNA cover, but they usually do their homework. I shouldn't affect the tune as the "O2" sensor readjusts the fuel input to the ECU table values and any extra is easily accommodated, even with a freer exhaust. It will be the same lean as std.
I agree about the airbox being a culprit, but disagree about the reason why ( My idea is that the 90deg apart intake overlap and side by side inlets, they are both sucking at the same air at the same time for part of their intake cycle).

[hordboy]

The cylinders are 270 apart, not 90. 
 

[gregjet]

Are you sure? Wow that sure changes the ideas I have about the exhaust. All the literature I have said 90deg, which makes sense if you have half mass balancing , effectively making it a V twin.
270 deg would get rid if the exhaust pulse phase overlap problem and any intake overlap. I need to do my homework as this rattles my whole approach.
Just checked the manual. It doesn't say anywhere but the crank pins are of course 90deg apart. So I checked the valve section and there it is. Cyl 2 follows at 270 deg. This is a seriously unusual config. I don't know of any other bike off the top of my head that does it this way. Nor why . But hordboy is completely correct, it IS a 270deg motor. Balance in theory won't be as quite as good ( though purely from a knetic mass point of view), but with balancing shafts it won't matter.
Now I have to find out why they used this config. I am seriously intrigued and excited. Our bike is even more unusual than I thought.
 
Please ignore ALL my exhaust and intake comments re the Phase overlap!
 

[rowdy]

Are you sure? Wow that sure changes the ideas I have about the exhaust. All the literature I have said 90deg, which makes sense if you have half mass balancing , effectively making it a V twin. 270 deg would get rid if the exhaust pulse phase overlap problem and any intake overlap. I need to do my homework as this rattles my whole approach.
Just checked the manual. It doesn't say anywhere but the crank pins are of course 90deg apart. So I checked the valve section and there it is. Cyl 2 follows at 270 deg. This is a seriously unusual config. I don't know of any other bike off the top of my head that does it this way. Nor why . But hordboy is completely correct, it IS a 270deg motor. Balance in theory won't be as quite as good ( though purely from a knetic mass point of view), but with balancing shafts it won't matter.
Now I have to find out why they used this config. I am seriously intrigued and excited. Our bike is even more unusual than I thought.
 
Please ignore ALL my exhaust and intake comments re the Phase overlap!

From Yamaha (yea... I know it's just PR bull, from the FZ-07 page) Crossplane Concept
This 2-cylinder engine features Yamaha’s “Crossplane Concept,” 270 degree crank that provides linear torque development in response to the rider’s throttle input. The FZ-07’s in-line 2-cylinder engine provides linear torque development, smooth torque characteristics and a strong feeling of acceleration in the low- to mid-rpm range along with pulling power that extends to the mid-upper rpm range. The CP2 engine is also light, slim and compact and offers an excellent level of rider/machine communication.
 

[gregjet]

When I bought the bike it definitely said "90deg" crank....The words revisionism spring to mind. I just found out that Triunph has used the 270deg crank in it's new twin as well. Might be a current "thing"

[hordboy]

The crank pins are 90 apart, or 270 apart, it depends which cylinder you call 0 degrees. It is indeed a 270 firing order. All 90 degree v-twins that I can think of are like this, Ducati, Suzuki SV/TL, Honda RC/VTR. It gives perfect primary balance in a v-twin. Yamaha chose it because they want to emulate that firing order in a parallel twin, but they can't get perfect balance, so... the counterbalancer. The old TDM was like this, and some Brit. parallel twins. It's not really unusual at all. They call it "cross plane," which is just marketing bs. It's not a new concept.
 
If you want truly unusual, look into the Honda 52 degree twins. They have 76 degree offset crank pins. This gives them balance "sorta" like a 90 degree, but the firing order is actually 232 degrees. (for balance, 232 + the avg of the crank pins (76/2) = 270) (or, 52 + 76/2 = 90)
 
Edit:  I should clarify a bit.  The Ducati/SV/RC engines mentioned have 90 degree offset between the cylinders, but a *single pin* crank.  This gives the 270 firing order.  (Horizontal cylinder fires first, then the vertical, 270 degrees after the front)  Whereas the FZ has both cylinders at 0 degrees but the crank pins are offset)  Clear as mud.
 

[mjh937]

I am sure I read that the new Africa Twin uses the 270° firing order too. There must be something to it for so many manufacturers to be doing it.

[Guest Ralph]

I have 2 parallel twins the 07 and a W800 Kawasaki, the W is a 360deg twin so
you get equal firing pulses, at 50/60 mph the 07 feels like it's just loping
along at low revs the W800 feels like it's revving it's head off even though
it's doing about 1000 rpm less, 270 deg cranks and V twins give this feeling
even though they are revving quite high, one of the things I like about them.
 

 
Don't think you get the W800 in the US but this is mine.

[peteinpa]

I think ALL vertical twins should be made this way. Standard twins: 180 degrees, 360 degrees, sound/feel hectic and boring. Fz-07 sounds like a Ducati! Awesome!
 
I'm going to remove the bottom part of my snorkel sometime soon. No other changes, rest of bike stock. 

[peteinpa]

It's raining today anyway so I trimmed the bottom tube of the snorkel off. on my (USA) bike it faces rearward. I removed the rubber part from the plastic part to trim it with a razor blade.
 
You could install it the other way in the plastic to make it face forward but I didn't.
 
Waiting to see if it drys up outside for a test ride.

[ssdawood]

So what's the verdict for stock bikes.
 
Keep the snorkel on and remove the baffle, the plastic piece on the other side.
 
I would like to try this.

[ssdawood]

It's raining today anyway so I trimmed the bottom tube of the snorkel off. on my (USA) bike it faces rearward. I removed the rubber part from the plastic part to trim it with a razor blade.  
You could install it the other way in the plastic to make it face forward but I didn't.
 
Waiting to see if it drys up outside for a test ride.

 
 
 
Is your bike stock. If yes, I would wait till you come back from your trip.

[Guest ChicagoAJ]

So what's the verdict for stock bikes. 
Keep the snorkel on and remove the baffle, the plastic piece on the other side.
 
I would like to try this.

Snorkel and baffle are the same thing (unless you're referring to the baffle from an aftermarket exhaust). The only part you should be taking out of your stock airbox would be the rubber snorkel. You can take it out and put it back in with no tools. You'll get a lot more intake noise with it out, power gains will be negligible.