Re: RE: Semi Hemi but totally ugly was:4.7l spark plug install & 3923questions

From: Marty Galyean (mgalyean@acm.org)
Date: Mon Sep 18 2000 - 22:21:14 EDT


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

Stlaurent Mr Steven wrote:

> Hmm! Like the old hemi the spark plug are located next to the intake
> manifold. They have coil over plug. As far as the space concern, plenty to
> work with. I agree with the air hat concern-BUTT UGLY. A TB intake tube
> may look a lot better than the plastic.
>
> -------------------------------------------
> 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: GSWillhite [mailto:GSWillhite@ualr.edu]
> Sent: Monday, September 18, 2000 1:00 PM
> To: dakota-truck@buffnet.net
> Subject: DML: Semi Hemi but totally ugly was:4.7l spark plug install
> & 3923 questions
>
> I stopped at the dealer today and checked out the 4.7L.
> Where the h#!! are the plugs? No offense,..oh maybe a little....
> The engine looked like a ferd powerstroke, butt ugly and
> no room. I'm glad its a good fast engine, otherwise I'd
> feel sorry for you 4.7 guys. I hope Mopar or someone will
> make some chrome valve covers for this engine soon. Mean
> while, please keep the hood shut on those things. Thank you!
>
> ;p (ducking and running)!
>
> GS -
>
> P.S. I'd rather have burnt knuckles!
>
> >
> > Yep, I do all 8 in less than 30 minutes, alot easier than burning and
> > bashing knuckles on the exhaust manifolds of the 5.9/5.2. Matter of
> fact,
> > I have swapped plugs out at the dragstrip between runs, no cool down, and
> no
> > burns!
> >
> > Matt
> >



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