[Joe Schmoe]

...most resonators are there to suppress sound. I suppose it's possible that it's there to cancel out some bad resonance that might interfere with air entering the intake manifold. Anyone have any idea why ours is there? I'm about to try replacing mine with a freeze plug (if I can find one that matches the diameter) to see what kind of effect it might have and figured I'd pose the question.

 

[SuperWhiteGT4]

...most resonators are there to suppress sound. I suppose it's possible that it's there to cancel out some bad resonance that might interfere with air entering the intake manifold. Anyone have any idea why ours is there? I'm about to try replacing mine with a freeze plug (if I can find one that matches the diameter) to see what kind of effect it might have and figured I'd pose the question.

I'm under the impression that it's for sound deadening. I usually block all of mine off, but for some reason, have never bothered to in the spyder.

Might I recommend checking the tops of various bottles and jars for a makeshift "freeze plug?"

 

[Levi]

It is to reduce the bad resonance in the intake. Basically it sucks up the waves that are coming out of the intake manifold back into the intake tube. It is for performance and that alone.

Look up miata intake helmholtz resonators which are identical to ours and they been dyno'd to show a 3-4 torque loss between 3-4k rpm. You would never feel this difference though.

 

[Joe Schmoe]

Fine..........I replaced it

 

[Kevin Beane]

The Helmholtz resonator tube is designed "just so" to give a mild (very mild) increase in performance in a specific RPM range (which depends on the length of that tube and other factors). It has to do with pulses in the intake tube and reinforcing some and canceling other frequencies. It also affects the sound of the intake, filtering out some higher frequencies and making it sound better. Not a big deal, but it was definitely engineered to be just so.