Marty,
Thats it! Throw in some active sound control (big voice coil in the engine
compartment) and we could get some serious "tuneable" sound... I can see the
Dak rolling down the street rumbling out the first lines to Iron Man....
EPC or bust!
BKB
----- Original Message -----
From: Marty Galyean <mgalyean@acm.org>
To: <dakota-truck@buffnet.net>
Sent: Wednesday, October 18, 2000 5:27 PM
Subject: Re: DML: RE: ABS looooong po'boy intake installed on 4.7 - wow!
> No idea of the length of intake runners. Bill C. on the list (SEMIHEMI01)
> suggested some kind of big ABS penny-whistle as part of the intake. I
pictured
> it driven by vacuum or motor that would always keep that growl at all RPMs
> rather than just 2200. That would give you the resonance, getting the
standing
> wave at the right phase would be the next part. Time for fuzzy logic to
step
> in. A feedback loop involving pressure diffs (amplitude) and phase of
column
> of intake charge or something like that. EPC. Electronic penny-whistle
> control.
>
> Bruce Bridges wrote:
>
> > Marty,
> > Yes! The engine will pull the intake tract through many "different"
> > frequencies. Its the one @ 2200 rpm that sets up a standing wave in the
> > intake tract and starts howling that you would want to eliminate! Much
like
> > the whistling FIPK syndrome! My thought was that the intake tract must
> > "play" with the resonant cavity tuning of the intake manifold, but cant
be
> > obnoxious under the normal RPM range. As a "constrained" factory
designer
> > with a lot of conflicting priorities Id be skeered to put a "Tune" to
the
> > intake tract for anything but noise reduction, knowing that the final
cut by
> > the QA group will be made on sound, not actual performance...Wimps...Any
Ide
> > how long the intake runners on the 4.7 are? I need to get under the
hood of
> > one soon...
> > Bruce
>
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