Quote:
Originally Posted by MauR
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I'n trying to understand how this baffle works but I'm not sure what to do.
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Mauricio,
You paid for a straight passage to exhaust gases with some attempt for attenuation of noise by absorption.
The excessive noise comes from the disturbance of the atmosphere that the sudden successive expansions of those gases going from high pressure (several atmospheres) to zero atm and subsequent speed produce.
Those are high pressure/speed pulses in the gas (high energy) that reach ears via the atmosphere.
The manufacturers use several methods of noise (energy) attenuation:
1) Using baffles and internal passages and tubes, they divert the flow back and forth and then make the pulses of one interfere with the pulses of the other (a
+ peak overlaps a
- peak, resulting in close to zero pressure.
Your DanMoto does not do that: it is a simple straight shoot.
Installing internal baffles and tubes and experimenting with the location of those could help you.
The main problem would be anchoring those things to the carbon-fiber shell.
2) The OEM mufflers also try cooling the exhaust gases between inlet and outlet, achieving less volume to be discharged, which equals reduced disturbance.
They do that using big shinning surfaces exposed to the air stream and keeping the gases moving back and forth within those surfaces.
Your exhaust gases reach the atmosphere hotter and occupying more volume.
3) They sometimes try creating noise absorbing internal walls with soft materials protected by some mesh or perforated sheets.
That works for the gases hitting those walls at relatively low speed, but does nothing for the gases that move faster by the center of the pipe.
That material tends to get burned and blown away, and needs periodic re-packing.
I believe that is the purpose of the double wall on the baffle of your DanMoto, which is doing some attenuation (if in good condition), but not enough for you.
