Hey Marty, so what happens when you removed the air hat and go with a tube
to the front? Will you loose the bottom RPM end ump or the reverse? Or it
is there for the sound effects?
-------------------------------------------
Steven St.Laurent
Test Engineer
Test Branch, GSD, MCTSSA
MARCORSYSCOM, USMC
760-725-2506 (DSN 365-2506)
Work:mailto:stlaurents@mctssa.usmc.mil
Home:mailto:saint1958@home.com
-----Original Message-----
From: Marty Galyean [mailto:mgalyean@acm.org]
Sent: Monday, September 18, 2000 7:21 PM
To: dakota-truck@buffnet.net
Subject: Re: DML: RE: Semi Hemi but totally ugly was:4.7l spark plug
install & 3923questions
While on the subject of the stock 4.7 air-hat...
I was taking a better look at the underside of it and I think I know why you
guys lose a bit of low end with the intake upgrades. They have a 'Bose
chamber' in the air hat which will make the intake resonate at a lower
frequency than the normal intake of that length would resonate. This will
cause the intake to have its peak ram effect at lower rpms. As some of you
may
or may not know, as the intake valves open and close, the charge accelorates
and brakes like a slinky or traffic. Given a certain desired resonance,
when
the valves open again, the air waiting outside is a pressure wave and not a
rarefied valley. Longer intakes lower this resonance, shorter raise the
resonant frequency. The frequence of the pressure waves is rpm dependent.
Those Bose desktop radios with incredible bass response for the speaker size
use the same principle. I know that some companies are experimenting with
variable tuned intakes that change resonance continuously with rpm.
I was thinking of sticking with the stock air had but put a solenoid driven
butterfly valve that closes the entrance to the chamber at higher rpms and
see
what happens. This should push the resonance back up where the higher rpms
can
make use of it.
Marty
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