Topic: 3d printing pod inserts for laminar flow

[BomberMann650]

The only issue with the gluteonmeter is the placebo effect.

It been a known phenomena in the "tuner" world.  That all sorts of bolt on gizmos are sold as "improvements" and "gains".  Folks install their "hi-perf" gadget and drive away happily into the sunset.  Never aware that their modification may have actually netted a 1 or 2 percent LOSS.

If you have someone from outside the r&d world that could volunteer as your test rider, that would be optimal.  Hopefully this individual would be an accomplished rider, and through a process of double-blind tests, you could develop a data pattern.

[MessnerMoto]

Simple FEA for fluids will do the trick...

I have a similar idea for my Mikuni rs34. The problem is the minimum thickness of wall when you do 3d print and quality of finish

SLA might be a strong candidate for those needs.  I've got a friend with a formlabs printer.  love how you did your pattern.  I was trying to wrap my head around lofting a series of channels in one go, looks like you did a circular pattern for each position to make life easier?

last picture you have division in 2D... extrapolate from there... It is not ideal can be done better

The point of sphere on top is to enlarge area on inlet side because I am planing to put some UNI filter which acts as a restriction.

[TwoTired]

As long as I can remember.  The homebrew test of vehicle's performance has been a 1/4 mile elapsed time measurement.  Most have access to a stopwatch.
Of course, that is mostly a test of WOT.  But, that is the ONLY performance reason to install pods of any type.

I recall the early days, us kids would remove the air cleaner from the car and be convinced it was going faster because it sure sounded like it from all the surplus intake noise.  But, at the drags it just wasn't so.

Same was true with the Honda 305 and removing the exhaust baffles.  Never actually went faster, just made a different sound, and we imagined that improvement in our butts.

It's remarkably easy to lie to oneself.  One of the reasons why test equipment was invented, I think.


Have you looked into the throats of a UNI pod? 20 years ago, they offered pods that had a velocity stack profile inside them.  Do they still?

[scottly]

i'm not sure how i'd simulate the pulsing flow that i assume is present on each carburetor.  ideas?

The assumption seems to be that turbulent airflow is the problem with pods, but with the pulses, the airflow isn't necessarily "laminar" in the stock intake ducts, anyway.
Laminar flow is when a fluid, including air, moves through a pipe, at such a rate that the outer layers nearest the pipe wall move the slowest due to friction, with each layer speeding up a bit as the layers slide past each other, until the center, where the fluid moves the fastest. If the rate of flow exceeds a certain speed, the friction between the layers creates eddy currents, which causes turbulence.
Laminar flow elements are used to measure flow, and do this by measuring the pressure drop across the element. In the attached pic, notice the difference in diameter between the input/outputs and the flow element. This unit was calibrated for an 8" H2O drop @ 100 CFM.

[754]

As long as I can remember.  The homebrew test of vehicle's performance has been a 1/4 mile elapsed time measurement.  Most have access to a stopwatch.
Of course, that is mostly a test of WOT.  But, that is the ONLY performance reason to install pods of any type.

I recall the early days, us kids would remove the air cleaner from the car and be convinced it was going faster because it sure sounded like it from all the surplus intake noise.  But, at the drags it just wasn't so.

Same was true with the Honda 305 and removing the exhaust baffles.  Never actually went faster, just made a different sound, and we imagined that improvement in our butts.

It's remarkably easy to lie to oneself.  One of the reasons why test equipment was invented, I think.


Have you looked into the throats of a UNI pod? 20 years ago, they offered pods that had a velocity stack profile inside them.  Do they still?

.
I pulled the aircleaner element out of my Beemer R100RT at the drags in Sturgis, after doing a few baseline runs. It picked up about 3/10 of a second or more in the 1/8 mile.. That would be about 1/2 sec in the 1/4......sweet..
 Then I pulled the pipes..sounded awesome, but now too lean so picked up no time.. The crowd loved the wheelie into second and the front wheel hop into third..
 Then I did a burnout.. K owing full well I cant dump the clutch..showing off.. That wounded the clutch and it started to slip.. Fun afternoon at the drags on a touring bike..
 You never know till you try.. In general Jap bikes are fairly well engineered.

[754]

I see this subject, pertnered with others on here to test, maybe showing some good results.

[RAFster122s]

Velocity stack designs have a critical mouth radius and square edges kill laminar/smooth airflow.  A foam Unipod has the air going through all kinds of direction changes to go through the filter foam.  That slows the air and as a result the air has been slowed somewhat and it creates increased suction by the motor pulling fuel.  This is true whether a Unipod or a Unifilter is used.

The other critical part of velocity stack design and use is that there is a radius around the mouth in all directions around that mouth that must be obstruction free for optimal performance.  So, if you bolt up a filter to the mouth of the stack you defeat the ability or impact the ability of the stacks from pulling the air into the carbs in a linear fashion.  The throat diameter at the carbs and the velocity stack height also has a multiplication factor for stack height as well as the mouth opening.  The venturi effect is being used to accelerate the air through the stack and that accelerated air naturally affects the fuel draw and the atomization. The skin effect of the material used for the stacks is a factor and is often why you see a good stack with a superbly mirror polished alumunium if made with aluminum. 
A screened stack often will provide only insect or rock or clumps of dirt protection and its negative impacts really defeat many of the benefits because of the turbulence introduced in the throat that kill the laminar flow aspects...ok not exactly kill but their negative inflence would be felt.  A stub stack, name of extremely short stack marketed by a company works inside a large filter and allows you to have many of the benefits of a stack without running a full stack and requiring as much depth/distance directly in front of the stack.
 A stack requires free air equal to the mouth diameter or stack length,
I think the former and not the later...but don't recall off the top of my head,
directly In front of the stack's mouth.  Beyond that distance you willbe able to put filter media provided it is not feeding turbulent air...for best operation of the stack.  That is why the ITG filter, airbox stack design that a group of SOHC4 members did a group buy after a member prototyped and built a few for 550 and 750 bikes.  They were in the 550-650 range as I recall as they were a very nice bit of kit providing a very nice flowing very low restriction solution to overbored and high performance motors allowing those motors to be supplied with all the air fuel mis they would need to tap into their performance potential and still provide a decent and reasonably effective filtration system, rather than running open stacks...

But, all that said, the distance between the intake for the heads and then the carb throat opening on intake side and then the frame tubes behind the tank and motor provide an obstruction for carbs #1 and 4 and that cannot be changed without re-engineering effort.  So, this is part of why you often will see different long term differences between the outside carb and inside carb's piston and  cylinder head build up of carbor or damage

Y

[Retro Rocket]

Velocity stack designs have a critical mouth radius and square edges kill laminar/smooth airflow.  A foam Unipod has the air going through all kinds of direction changes to go through the filter foam.  That slows the air and as a result the air has been slowed somewhat and it creates increased suction by the motor pulling fuel.  This is true whether a Unipod or a Unifilter is used.

The other critical part of velocity stack design and use is that there is a radius around the mouth in all directions around that mouth that must be obstruction free for optimal performance.  So, if you bolt up a filter to the mouth of the stack you defeat the ability or impact the ability of the stacks from pulling the air into the carbs in a linear fashion.  The throat diameter at the carbs and the velocity stack height also has a multiplication factor for stack height as well as the mouth opening.  The venturi effect is being used to accelerate the air through the stack and that accelerated air naturally affects the fuel draw and the atomization. The skin effect of the material used for the stacks is a factor and is often why you see a good stack with a superbly mirror polished alumunium if made with aluminum. 
A screened stack often will provide only insect or rock or clumps of dirt protection and its negative impacts really defeat many of the benefits because of the turbulence introduced in the throat that kill the laminar flow aspects...ok not exactly kill but their negative inflence would be felt.  A stub stack, name of extremely short stack marketed by a company works inside a large filter and allows you to have many of the benefits of a stack without running a full stack and requiring as much depth/distance directly in front of the stack.
 A stack requires free air equal to the mouth diameter or stack length,
I think the former and not the later...but don't recall off the top of my head,
directly In front of the stack's mouth.  Beyond that distance you willbe able to put filter media provided it is not feeding turbulent air...for best operation of the stack.  That is why the ITG filter, airbox stack design that a group of SOHC4 members did a group buy after a member prototyped and built a few for 550 and 750 bikes.  They were in the 550-650 range as I recall as they were a very nice bit of kit providing a very nice flowing very low restriction solution to overbored and high performance motors allowing those motors to be supplied with all the air fuel mis they would need to tap into their performance potential and still provide a decent and reasonably effective filtration system, rather than running open stacks...

Uni make a system that you can run with velocity stacks, its been brought over from weber carb filters they've made for cars for years... Quad Pods, they make them for most motorcycle carb spacings...

http://www.uniflow.com.au/contents/en-us/d361_Quad_Pods.html