You could easily make one for 5,000 RPM. The ones on cars now are made to coincide with a particular RPM (peak HP, I think).

As for the valve spring thing, I don't think so. The resonator acts to push an acoustic pressure wave into the intake valve when it opens.

But if you can set it up such that the pressure wave is negative at valve closing time....

You lose volumetric efficiency and you burn more gas.

Which is exactly the opposite of what it is designed for, which is that it's resonant frequency is the same as a particular frequency of valve openings.

Kind of backwards, right?

Well yes, but you also have to have a negative wave at some point, I'm just wondering if it can be synched slightly off to help snap the valve shut, rather than at some point after valve closing, or during valve opening.

Would totally depend on the duration though, obviously it would come naturally with 180* duration at the point of resonance. However you might be working with 2nd or 3rd harmonics to fit it in the duration otherwise.

Well, since the waves are probably very close to SHM, I can't see how you could have them both push air in and simultaneously pull it out.

From a friend who designed them, the resonators are only good for about 10hp or so, so I can't imagine there would be enough force/power to help shut the valves when compared to the spring rates of the valve springs.

Possibly not, but if there's 1 oz more on one side of a seesaw, it still stays tipped, the same as if it had 10lb on it.

The resonance pushes AND pulls though, it's all in the timing, it doesn't push and pull at the same instant, it pushes then half a wavelength later pulls back, by the time the air is springing back though, the valve is closed so it doesn't matter... but if there was an advantage to timing it to pull at the last instant before closing, to help weaker springs overcome the inertia of the valvetrain....

ok so as you guys know i took out the resonator and to my surprise i actually have been getting the same, or better fe readings! is this typical?

Come to think of it, if it was in the bumper area it was just a silencer type. These actually kill some intake velocity because they work on the destructive interference principle.

Silencer or intake pulse tuner, I don't know which but my car has a big resonator on the intake pipe, I was thinking of half filling it with water to make the intake air more humid. Just to see what'd happen.