I wondered what that was, but apparently i wasn't thinking on the level you
were at the time... I agree with you now and that is really cool. I'm going
to redesign my poor boy tonight.
Sean Bruckman
----- Original Message -----
From: Marty Galyean <mgalyean@acm.org>
To: DML <dakota-truck@buffnet.net>
Sent: Tuesday, September 19, 2000 9:25 AM
Subject: DML: Why the stock 4.7 air hat is special
> I posted this replying to the spark plug thread and there was no
> response. So now I'm giving it its own subject. C'mon guys, its
> not _that_ boring. Don't leave me hangin'!
>
> I was taking a better look at the underside of the stock 4.7 air
> hat 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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