question: the mod is an additional resonating structure installed within
the stock box?
thx,
PeteZ
On Thu, Mar 30, 2023 at 8:25=AFAM Area-51 <goldsteinindustrial@gmail.
com>
wrote:
> goldsteinindustrial@gmail.com>
>
> An update on yesterday's recon into an exhaust muffler... spent the day
> trying a few different things mods; all that was mostly achieved was a
> transposition along the frequency band but not much db reduction... gave
up
> for now and went back to testing the carbi box... and...
>
> Well as expected 181's stock factory air box did pretty much zip to shut
> things up; on average about 3db across the whole range. Then the Mod box
> got some scrutiny.
>
> Mod box rocks... on average around 25db to 40db reduction through the
> target range; WOT rpm primary frequencies are returning up around 30db an
d
> secondary harmonic ranges are returning around 15db reduction.
>
> Will have to build this Mod box and see if the actuals match!
>
> A 25db noise reduction from the engine will make eating cheese inflight
> more enjoyable again.
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=510554#510554
>
>
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