Importance of the Helmholtz Frequencies

Yay! Well don't be shy about learning scientific things these are real-world things that can help us have a really nice engine. Helmholtz? Sounds like another ridiculous city in Austria where they make a special beer or sausage. Mr. Hermann von Helmholt was a famous German scientist/physicist that developed a great theory on resonant frequencies in air cavities. Just imagine yourself blowing over the top of a bottle and creating a sound. Or you can think of that special person blowing over the top of your "bottle" and you making a sound. Somthing like that. Well Mr.Herms Helmholtz found that different volumes of air create different frequencies.

What exactly happens is that when you blow or she blows air into a cavity the pressure inside the bottle increases. In essence imagine yourself blowing a packet of air at the opening of a bottle. This backet of air will go down the bottle neck only so far if you can imagine the whole chamber to be an "air spring" When the packet of air comes back out because the effects of it hitting the "air spring" some of the air inside will leave the bottle. Because the "air spring" must come to a rest and try to achieve the outside pressure it will actually suck back some air to make the whole system stable.

Kinda cool. Why is that so cool? That is why acoustic guitars have that hole right in the middle. This applies to us because engines have ports on the intake manifolds and exhaust manifolds. So effectively we ca "tune" these manifolds to work in line with the correct frequencies that are associated with the proper power band. Yay! That means extra power for making things longer or shorter.

That is why Bisimoto is the fastest all-motor Honda guy in the world. He "tunes" his intake manifold lengths and his exhaust manifold for maximum efficiency.

Check out this air box made by BMW. These "tuned" boxes give the appropriate resonances to promote extra sucking from naturallly aspirated engines. $2300 MSRP. Niiiiceee!