Well he has two bikes so I am thinking its the FBW version. And no you really cannot tame it. I can tell you that the Heavy breather intake is by far the loudest of them. Very much like cars they have long intake tubes with resonators built into the intake tube for this very reason. His intake has to be able ot feed the 124 and what he has is middle of the road. Now maybe a heavy breather with some mods to the tube with baffles .. but in the end you are dealing with such a short workable area of intake tract.
Here is a few things you deal with, With the FBW bikes the plates is also bouncing and that has made it known to the HD world. On a cable bike the plate will not bounce so the noise is greatly reduced or none at all. The car world has struggled with this for many years. The cams we use create it as well. Its louder on the 14 cam than on the 13 cam. As with the 14 we have some overlap where as the 13 cam was negative.
On the bikes its a issue and not much that can be done about it. Redmtcyl pulled a cam as he did not like the noise it made . Maybe he will post up on that.
This is more so car stuff I deal in that as a fun factor with a race car. But gives you an idea of how much tech so to speak goes into the air intake. HD runs a air cleaner with there parts that works. Take that unit off install a heavy breather even with a stock cam and you can hear it.
Pressure Wave Harmonics
Air flowing into your cylinder head's intake port doesn't move in a straight line while the valve is open, then politely stop in its tracks to await another valve opening. When the valve closes, the moving column of air slams into it, then compresses and bounces back like a spring. This pressure wave travels backward at the speed of sound until the intake runner opens up or it hits something, and then it bounces back toward the cylinder. This is the "first harmonic." The pressure wave actually bounces back and forth it may be two or three more times before the intake valve opens again.
Intake Tube Pulses
The resonator in a vehicle intake is technically known as a Helmholz resonator, an acoustic device used to control pressure wave harmonics. Air bouncing back out of your engine and into the intake tube doesn't do it in a single pulse the way it would in a single intake runner; the multiple pistons put out pressure waves at their own intervals, and some of those are going to try to bounce back in while others are going out. The result is a "clog" or high pressure area in your intake tube that ultimately limits airflow through almost the entire rpm spectrum.
The Resonator
Adding an expansion chamber to the intake tube forces air coming back out of the engine to slow down to fill the cavity, thus expending a great deal of its energy and slowing the pressure wave reversion. This slowdown allows fresh air to flow toward the engine without fighting pressure reversion waves the entire way, thus aiding in cylinder filling. Since these pressure waves are essentially sound, giving them a place to expend their energy before exiting the air filter box ends up dampening the intake noise and quieting the engine. Thus, the resonator helps to make the engine paradoxically quieter and more powerful. Seeing these test done on a chassis dyno with the race car is funny as my race car see double duty. Street strip I had to find the middle ground on that vehicle. With the most air flow it made a very small % more power. However the noise it made was awful .
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Topic: Intake Valve Noise vs Pinging? (Read 8389 times)