Re: RE: Re: RE: Re: 4.7 Air Intake Doomed

From: Bruce Bridges (bbridges@flometrics.com)
Date: Wed Oct 25 2000 - 11:00:19 EDT


Steve,
The variable venturi is a way the Mopar designers used to linearize the
response of a butterfly valve. Linear response curves (flow rate vs.
angular possition of butterfly) makes for easier computer control and a more
"predicatable" off-idle response (no "jump")... Butterfly valves are very
non linear through the first 15% of rotation. Mopar shrouds that area by
actually milling a 68mm ball in the throat of the TB that intersects the
above plate bore, shrouding the front and rear of the plate. If this was
done "perfectly" with venturi shaping etcetc. then very little pressure
would be lost and the flow rate for a given vacuum would be about what a
sraight bore of the same throat size can provide (65mm?... not sure my 4.7
TB is off at the machinists being mic'd).. anyhow, since they have to make
these things (TBs) in the real world, their "venturi" doesnt recover
pressure in an ideal fashion due to machining feasibility and they restrict
the flow! It should be interesting to see how the variable idle "problem"
and all that Ive heard about the 4.7 computer controls changes with the TB
design...
Bruce
----- Original Message -----
From: Stlaurent Mr Steven <STLAURENTS@mctssa.usmc.mil>
To: <dakota-truck@buffnet.net>
Sent: Wednesday, October 25, 2000 11:07 PM
Subject: DML: RE: Re: RE: Re: 4.7 Air Intake Doomed

> Off idle? English please...
>
> -------------------------------------------
> 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: Bruce Bridges [mailto:bbridges@flometrics.com]
> Sent: Wednesday, October 25, 2000 2:35 AM
> To: dakota-truck@buffnet.net
> Subject: DML: Re: RE: Re: 4.7 Air Intake Doomed
>
> Not sure yet... We just got the stock TB from Mopar... Not much meat to
port
> it with (not a problem for us) but it does have the variable venturi
design
> for off idle lack of response...
> Bruce
> ----- Original Message -----
> From: Stlaurent Mr Steven <STLAURENTS@mctssa.usmc.mil>
> To: <dakota-truck@buffnet.net>
> Sent: Wednesday, October 25, 2000 7:40 PM
> Subject: DML: RE: Re: 4.7 Air Intake Doomed
>
>
> > What size is the new TB Billet for the 4.7 in MM?
> >
> > -------------------------------------------
> > 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: Bruce Bridges [mailto:bbridges@flometrics.com]
> > Sent: Tuesday, October 24, 2000 10:26 PM
> > To: dakota-truck@buffnet.net
> > Subject: DML: Re: 4.7 Air Intake Doomed
> >
> > Chris,
> > F&B (Flometrics and Bridges) will be prototyping a Billet TB for the 4.7
> in
> > a couple of weeks. We are planning on increasing the inlet diameter of
> the
> > TB to at least 4" (from the 3.26 stock..) This will require a new
intake
> > system or adaptor, which we will under take as well...We need a 4.7
truck
> to
> > come on down to the shop for some prelim measurements and then install
and
> > dyno testing...about 2 weeks later... Discounted TB and etc, is all part
> of
> > the deal!
> > Takers?
> > Bruce
> > ----- Original Message -----
> > From: <Y2KDakuda@aol.com>
> > To: <dakota-truck@buffnet.net>
> > Sent: Tuesday, October 24, 2000 7:55 PM
> > Subject: DML: 4.7 Air Intake Doomed
> >
> >
> > > Well sorry guys I have given up on my sorce for the new 4.7 intake.
the
> > guy
> > > has not returned my e-mail and its not right to make people wait this
> long
> > > for information. I just ordered the Z-Tube from Intense Performance it
> was
> > a
> > > little more but after some thought a much better product. Sorry again
> that
> > i
> > > couldn't come through for you guys but I tried it is his loss. If you
> > still
> > > want his product you can keep trying to e-mail him.
> > > Thanks
> > > Chris Lambert



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