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Old 03-02-2010, 08:44 PM   #12
Topless
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Join Date: Nov 2006
Location: Southern ID
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QUOTE=Steve Tinker]Chris - I would be carefull about removing the Helmholtz resonator - I removed mine on my Mazda Miata and immediately lost about 25% of available torque below 4000 rpm.
It sounded better but after about a week I was convinced that I was missing something driving around town - I was, about 25 lb ft of torque which I immediately regained when I reconnected the resonator (they are removable on the Mazda). I thought that they were fitted for only noise supression but an ex Mazda man on the MiataForum confirmed that after lots of testing at the factory, the engineers found the sound wave harmonics actually improved cylinder filling at low to medium revs.[/QUOTE]

Confirmed. That silly little box thingy (Helmholtz resonator) in the intake serves two purposes: Noise suppression and improved midrange torque. It is part of a "tuned intake" and removing it may leave a trough in your torque curve. Caveat, I have not done the math on this but I am betting a bright engineer in Stuttgart has.

For more info on what it is and what it does: http://www.sae.org/technical/papers/2005-01-3803

Ultimately though it is your car and you can mod it as you see fit. I am just passing on what I know about the intake resonance concept. My dad designed "tuned jet engine intakes" for Northrop and Rohr. Intake resonant frequency and acoustic standing waves were regular dinner table conversations, much to my mothers disappointment.
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Last edited by Topless; 03-03-2010 at 06:55 AM.
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