Have you seen or done the stock boxes for comparison? I'm curious how the two look next to each other.
CB360 Airbox design
- Thread starter Bucky685
- Start date
I have little-to-no idea how much effort went into generating these models, but if you're able to easily tweak things, it might be worth offsetting the endcap openings so that the circles formed by the opening and the end of the airbox are no longer concentric. This will help to promote a swirling effect which, in turn, may increase flow. It's a common practice nowadays when intake ports meet intake valves to have the port biased toward one side or another.
Are you sure this is right? Swirling is turbulence. In an intake manifold, the function of swirling isn't increased flow, but better distribution of fuel in order to create a more homogeneous fuel-air mixture. I realize we're talking about the inlet side, but I wouldn't think the physics would change.Sonreir said:
Swirling does promote better atomization as well as helping to eliminate hot spots within the combustion chamber, but it also increases flow. Swirling air molecules tend to align in all the same pattern rather than fight against one another. This is what happens in practice when you fit velocity stacks on your bike.
You can also see it in effect when you pull the plug on the bath tube. The water will naturally begin to swirl on it's own, but will begin swirling earlier if you give it a bit of help (which is what we're doing when we offset the intakes).
You can also see it in effect when you pull the plug on the bath tube. The water will naturally begin to swirl on it's own, but will begin swirling earlier if you give it a bit of help (which is what we're doing when we offset the intakes).
Velocity stacks reduce swirl. They increase air flow because of laminar flow. So particles remain parallel. With swirl, particles can move at different arcs. The increase in turbulence from swirl in an intake manifold allows more fuel to burn, thereby creating more efficient combustion. Swirl also created more even heat distribution, like you said, so no hotspots. But that's also an agent of more fuel burning across the pattern. My experience is from kiln and burner design not carburetors, but I can't see things being that different. Burners have venturi's which increase flow. As I understand it, carburetors are also venturi's. So flow is increased by the vacuum of the venturi effect within the carburetor. That effect is helped by a velocity stack because of the laminar flow of particles drawn through the velocity stack by the vacuum within the carb.
Bucky685
Been Around the Block
I re-ran the silumation, with a offset inlet filter. The inlet in also larger. I offset them to the rear. I did reduce the amount recirculation in the pipe.
I feel the air flow is pretty low compaired to the air box size. Offsetting the inlet from the filter to the rear smoothed the flow into the velocity stacks.
I feel the air flow is pretty low compaired to the air box size. Offsetting the inlet from the filter to the rear smoothed the flow into the velocity stacks.
Attachments
And how about if widen the stacks' bellmouths introduce a taper of 6° such that the diameter remains the same at the carb inlet? If possible, the bellmouth on the stacks may benefit from a tighter and more complete radius (something in the neighborhood of 180°, if that's doable).
I realize the simplicity of the simple tube of the main air chamber, but it looks like the air making a full 90° turn might be causing most of the turbulane. What happens if you "cut" the tube in the middle and make it more of a v shape? I don't think the angle would need to be extreme, but it might help to get the air flow started in the right direction which should help direct it to the correct intake port.
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liam
1970 cb350/1980 xs250/2004 klx400/BMW E30 323I
i like this and was thinking of doing a similar thing for my cb350, mostly to be able to use car filter elements or a washable foam filter. the lack of technical knowledge has stopped me so far though.
while you've got the computer cranked, you might like to take into account the external airflow past the intake mouth at riding speed, and do a few different analysis for zero airspeed at idle and high speed at wot, then maybe play with the shielding of the intakes to get a controlled stable environment if there is a big difference.
while you've got the computer cranked, you might like to take into account the external airflow past the intake mouth at riding speed, and do a few different analysis for zero airspeed at idle and high speed at wot, then maybe play with the shielding of the intakes to get a controlled stable environment if there is a big difference.
mechdesign2k4
Chop-N-Change
Well your inspiring me to fire up solidworks and the 3d printer at work.
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possible seat for a turbo in this design 8) ??maybe its possible to fit in.
ROLL OF THUNDER...
ROLL OF THUNDER...
mechdesign2k4
Chop-N-Change
Bucky685 said:
i didnt see a vm26 so i'm out of luck. I use that site tons......
