Intake Flow Simulation - ADDING INTAKE VELOCITY STACK

[sansnombre]

I was going to use several pressure diff (inlet to outlet) but then realized I'd get all the info I was looking from a single run. That run is at std atmospheric pressure at sea level at the inlet side of the airbox.
 
The exhaust side is -3 inches water. That was somewhat arbitrary, but is where DNR was running their reference pressure, so I chose that one, planning to also bring it down to 1.5" as K&N uses, but I really don't think it makes that much difference - actual flowrates, yes, but I'm looking at relative flowrates, and they should be pretty close in percentage regardless of the pressure differential, as long as it's reasonable.
 
The entire simulation is quite limited, and I'm just looking at steady-state differences in flowrate with the changes to answer basic questions of is this better than that. Not looking for actual flowrates, just the flowrate changes due to gross geometry changes.

[norcal616]

What I don't see is a comparison between the air volume the motor needs at various rpms and the airbox style to effectively provide that volume of air for the various rpms... I apologize if this question has been answered...

[sansnombre]

That is actually beyond the scope of what I'm doing here.
 
I'm not looking at dynamics, and even the flow is greatly simplified - in real life we have pressure pulses within each tract coordinated with RPM and also an alternating of pulses between the two tracts. In addition, I'm not look at compressibility or energy losses or any of that real life stuff. Simulating that is a major undertaking, and doing that per RPM adds that much more work, and it's not necessary to answer the questions I'm trying to answer. This is a greatly simplified analysis and the answer at this flowrate will be almost certainly the same for other flowrates (RPM).
 
What I'm doing here is very simply looking at the flow within the airbox only under a given pressure differential at steady-state. Then varying the geometry of the components to see what kind of effect we'll see to the flowrate. This is to answer questions like should we take out the snorkel? is the MWR better than stock? should we remove the internal section of the snorkel? etc.
 
3" water for a pressure differential is on the high side I think, but it doesn't really matter to what I'm doing. I'm not looking for accurate flow data, just relative.
 
For this analysis, it would be overkill to have a bunch of different pressure differentials, as they all would essentially same the same thing: this is better than that or this is worse than that.
 
Hopefully it provides something of value; I've been able to glean quite a bit from it and actually pulled the entire snorkel out after running that one simulation!

[sorkyah]

I was going to use several pressure diff (inlet to outlet) but then realized I'd get all the info I was looking from a single run. That run is at std atmospheric pressure at sea level at the inlet side of the airbox. 
The exhaust side is -3 inches water. That was somewhat arbitrary, but is where DNR was running their reference pressure, so I chose that one, planning to also bring it down to 1.5" as K&N uses, but I really don't think it makes that much difference - actual flowrates, yes, but I'm looking at relative flowrates, and they should be pretty close in percentage regardless of the pressure differential, as long as it's reasonable.
 
The entire simulation is quite limited, and I'm just looking at steady-state differences in flowrate with the changes to answer basic questions of is this better than that. Not looking for actual flowrates, just the flowrate changes due to gross geometry changes.

 
 
So many ideas... i just cant put em into words
 

[sansnombre]

If interested, I finished the prototype of the external filter and you can see it here . . .
 
https://fz07.org/thread/7851/prototype-intake-filter-external-airbox

[crsnhppr]

I removed the airfilter, snorkel, and snorkel plate... bumped up fuel on my ejk and got a hell of a midrange kick outta it

[rhb]

MY MT07 had this stock
 

 
and now has this, my lid with DNA filter
 

 
Does not take rocket science to see the potential for improvement brap brap
 
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[Guest 2wheeler]

MY MT07 had this stock 

 
 
 
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WOW, it's amazing the difference between the US FZ model and the MT model!!! 
The US model doesn't have any of the anti-pollution crap the MT has. The US just has the snorkel with a larger diameter and much shorter snorkel centered in the lid with none of that portion with the hose connecting to it. I am betting that the stock MT version really sucks power compared to the US.
 
 
 
 
 

[rhb]

MY MT07 had this stock 
 
 
 
 
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WOW, it's amazing the difference between the US FZ model and the MT model!!! 
The US model doesn't have any of the anti-pollution crap the MT has. The US just has the snorkel with a larger diameter and much shorter snorkel centered in the lid with none of that portion with the hose connecting to it. I am betting that the stock MT version really sucks power compared to the US.
 
 
 
 

Its actually a noise abatement device vacuum operated at certain rpms in order to cut down on intake noise, euro 3 compliance. There is a flap that opens and closes at the back. I first just disconnected the vacuum diaphragm and removed it leaving the flap open and a gaping hole where the actuator sat. But we got the sexy turn signals
 

[sansnombre]

@crsnhppr You're running without any intake filter? Hmmm . . .
 
The setup you describe is what I think created that torque curve on the first page of this post - it's what I'm after as well, but with a filter and 24-7 reliability.
 
If I was to guess right now on the final results, I'd say the DNA or the MWR with their respective covers and a reflash is the way to go. The other changes are too subtle to have any meaningful difference.
 
The only caveat is whether the presence of the filter in the airbox is "blocking" the ducts. If so, moving it externally resolves that issue and also effectively increases the airbox size, and that I understand is a positive thing. I have another couple of runs to do and see if that is something that is likely. If so, to the dyno with the new design and I'll do back to back experiments and see what's what. But if there are changes, I'm not thinking they're huge, just optimizing the midrange . . . hopefully.

[sansnombre]

Bump - Conclusion posted.
 
See here https://fz07.org/thread/7952/airbox-modification-simulation-testing-conclusion

[pattonme]

Very interesting thread. The wide-mouth air-box opening and hard-bottom filter makes sense. Personally I would put some 6mm dia holes along the length of the engine inlet runners. Runner length influences pulse timing and thus torque so I wouldn't put them close to the airbox outlet. The idea being to alleviate the "cramped" pickup at the back of the air-box where the air has to make a few turns to get back there. But what we really need to see is a pressure gradient map as the intake valves open and close. I suspect you'll see 'red' for high flow across the filter element closest to the pickup and a large amount of "idle" air in the front of the box that meanders to the back in response to vacuum.
 
I was disappointed that the 35mm shorter stacks didn't show any benefits. I wonder if a slash-cut would help...

[Allan]

Really interesting. Being a senior engineering student, I thoroughly enjoyed this. It just goes to show you the Yamaha engineers seemed to make the best choice on design for the every day rider. we don't need that extra .5 hp for the common everyday biker. You tried so hard and got so far, but in the end it doesn't even matter. (RIP Chester)

[rhb]

Really interesting. Being a senior engineering student, I thoroughly enjoyed this. It just goes to show you the Yamaha engineers seemed to make the best choice on design for the every day rider. we don't need that extra .5 hp for the common everyday biker. You tried so hard and got so far, but in the end it doesn't even matter. (RIP Chester)

I would say not .5 HP but a 5 -8 HP, plus improvement overall mid range performance, not trivial to those of us who enjoy a well tuned machine. The Yamaha engineers are only constrained by price point which generalizes the performance curves to be within budget applied to the average rider. As an engineering student byou understand the role of engineering is to bring to the table the best solution for the least amount of money.
Anybody can design something outstanding for an unlimited budget.
 

[pattonme]

Anybody can design something outstanding for an unlimited budget.

 
You'd think so, but considering how often F1 stuff breaks from something as innocuous as running over a curb... Seems they forgot one of the tenants of engineering - don't make it so damn light/fragile that it won't make it to the end of the race. No finish, no points, no glory. Just astounding to me.
 
back on topic ...

[sansnombre]

@rhb Sadly it doesn't often work that way: "The Yamaha engineers are only constrained by price point."

 

I am a mech eng and have worked in semiconductors most of my career and am now a design engineer. As our young friend will find out once he enters industry as an engineer, in most cases "the best" is not what they're shooting for; you simply don't have the time nor the resources to search for it. And that is getting worse with time-to-market pressures becoming even higher. What they want is something that works well but takes as little resources and time as possible.

 

You can make the case that on their flagship models they have higher R&D investments and their guys are given more latitude for getting that best, but this is because having the fastest or the most HP translates into sells and kudos for the company. But generally, as a design engineer, they want you to make it a solid design, that is cheap, that can be produced effectively, can be put into manufacturing without issue, and doesn't cause problems post-sell. Most of the time, you have to get into non-production, niche design to be able to have the latitude to really figure it out and get the best performing product with trial and error or CFD, etc.

 

It's almost always a compromise, generally speaking.

 

 

[digitalsteve]

Can I get a dumb person recap here?
Is the consensus for the FZ-07, MT-07 and MT-07 HO (aussie model that isn't restricted) that unless you're installing a Hordpower setup, leave the airbox alone?

[norcal616]

15 minutes ago, digitalsteve said:

Can I get a dumb person recap here?
Is the consensus for the FZ-07, MT-07 and MT-07 HO (aussie model that isn't restricted) that unless you're installing a Hordpower setup, leave the airbox alone?

yup...

[sansnombre]

11 hours ago, digitalsteve said:

Can I get a dumb person recap here?
Is the consensus for the FZ-07, MT-07 and MT-07 HO (aussie model that isn't restricted) that unless you're installing a Hordpower setup, leave the airbox alone?

I'd say remove the snorkel and get a reflash.

[digitalsteve]

10 hours ago, sansnombre said:

I'd say remove the snorkel and get a reflash.

Doesn't sound like it's worth it, unless doing a Hordpower box.

A reflash on its own is probably still worth it.

[stickshift]

Removing the snorkel and adjusting the fuelling to suit (I use a PCV) led to a definite increase in power and improved throttle response on my bike.

[gregjet]

On a stock unflashed bike, the snorkel removal  will result in only a small increase in air flow and well within the range of self adjustment of the ECU/O2 sensor circuit. That's what it's for. The thing to remember it it readjusts to the same fuel table which is not optimium AFR.

If you reflash and still have the O2 sensor in the circuit it will readjust to the correct values. If you have a PCV you will have to do the adjustment unless using the wideband sensor and pcv.

[digitalsteve]

1 hour ago, gregjet said:

On a stock unflashed bike, the snorkel removal  will result in only a small increase in air flow and well within the range of self adjustment of the ECU/O2 sensor circuit. That's what it's for. The thing to remember it it readjusts to the same fuel table which is not optimium AFR.

If you reflash and still have the O2 sensor in the circuit it will readjust to the correct values. If you have a PCV you will have to do the adjustment unless using the wideband sensor and pcv.

I was thinking about using a DNA filter setup (so that ditches the snorkel) and getting a FTECU rig and maybe running the ActiveTune setup.

[sansnombre]

@digitalsteve

 

Depends what you think is worth it - the tuners, the ones who do the actual testing and see the results, all recommend removing the snorkel, esp if you are reflashing. Since it takes about 10 seconds to do it and costs nothing, and it's worth a HP or two, it's what I recommend.

 

There are actual dyno graphs of snorkel in/snorkel out floating around this site - same bike, same day, one with snorkel in, one with snorkel out, and the snorkel out makes better power.

[digitalsteve]

5 minutes ago, sansnombre said:

@digitalsteve

 

Depends what you think is worth it - the tuners, the ones who do the actual testing and see the results, all recommend removing the snorkel, esp if you are reflashing. Since it takes about 10 seconds to do it and costs nothing, and it's worth a HP or two, it's what I recommend.

 

There are actual dyno graphs of snorkel in/snorkel out floating around this site - same bike, same day, one with snorkel in, one with snorkel out, and the snorkel out makes better power.

Do you literally just undo the seat and yank it out?