RE: [DML] Re: Carburetors suck.
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RE: [DML] Re: Carburetors suck.



An example of where carb tend to fall flat is the example of changing
elevations... as atmospheric pressure falls it greatly effects the final
mixture.

This is one instance where the kjet system shines even better than the early
EFI systems.  Because of the mechanical components and the lambda sensor the
is a sort of built in compensation. I can attest to this as when I am on
long trips my car tends to go through many different altitudes (0-~4200ft)
and it is a great drive.

The early EFI systems (think early GM TPI/MPI) just took an atm sample at
startup. This meant you started running lean as you climbed (not as bad as a
carb due to lambda correction) but if you periodically turned the engine off
and on again it would re-sample and restore balance.

I am diverting a bit but the end result is that atmospheric pressure is not
constant and carbs have trouble dealing with it.

Again... this is just one example situation that carbs don't handle well.

Richard

-----Original Message-----
From: dmcnews@xxxxxxxxxxxxxxx [mailto:dmcnews@xxxxxxxxxxxxxxx] On Behalf Of
content22207
Sent: Wednesday, April 11, 2012 1:23 PM
To: dmcnews@xxxxxxxxxxxxxxx
Subject: [DML] Re: Carburetors suck.

  

You are joking? This is pretty elemental stuff:

Pressure of the air stream drops as it speeds up through the venturis.
Atmospheric pressure pushes fuel from the bowl into the air stream. Voila --
as long as a healthy engine is turning and there is fuel in the bowl, you
have fuel delivery (vacuum tight intake manifold of course). 

Bill Robertson
#5939

--- In dmcnews@xxxxxxxxxxxxxxx <mailto:dmcnews%40yahoogroups.com> , "Martin
Gutkowski" <martin@...> wrote:
>
> A beautiful example of you deflecting that which defeats your own
argument. Did you even read past the subject? 
> 
> I'm not even sure you know *how* a carb works... Venturi effect? static
versus total pressure? Surprise me....
> 
> Martin
> 
> Sent from my BlackBerryR
> 
> -----Original Message-----
> From: "content22207" <brobertson@...>
> Sender: dmcnews@xxxxxxxxxxxxxxx <mailto:dmcnews%40yahoogroups.com>
> Date: Wed, 11 Apr 2012 19:59:19
> To: <dmcnews@xxxxxxxxxxxxxxx <mailto:dmcnews%40yahoogroups.com> >
> Reply-To: dmcnews@xxxxxxxxxxxxxxx <mailto:dmcnews%40yahoogroups.com>
> Subject: [DML] Re: Carburetors suck.
> 
> Point of order: PRV's themselves suck. All a carburetor does is respond to
that suction as it passes through.
> 
> Bill Robertson
> #5939
> 
> --- In dmcnews@xxxxxxxxxxxxxxx <mailto:dmcnews%40yahoogroups.com> , Marc
Levy <malevy_nj@> wrote:
> >
> > "All metering is accomplished by air flow alone"..
> > 
> > Exactly the point Bill- What about air temperature? Air density?
ignition timing? fuel quality? All moving targets that a carburetor had no
way of compensating for.
> > 
> > There is a reason complex fuel injection systems have come to replace
the simple (and complex) carburetors of the past. 
> > 
> > 
> > --- On Wed, 4/11/12, content22207 <brobertson@> wrote:
> > 
> > > From: content22207 <brobertson@>
> > > Subject: [DML] Re: Carburete a DeLorean at DCS'12?
> > > To: dmcnews@xxxxxxxxxxxxxxx <mailto:dmcnews%40yahoogroups.com>
> > > Date: Wednesday, April 11, 2012, 3:19 PM Also FYI:
> > > 
> > > Speaking for the Autolite/Motorcraft 2100 only:
> > > 
> > > Unless the carburetor itself physically changes (gets dropped & 
> > > cracked, stagnant fuel turns to varnish inside, jets are 
> > > purposefully unscrewed and swapped out for different sizes, etc) 
> > > it will "hold its tune" into perpetuity. Not counting the 
> > > accelerator pump and the full throttle enrichment valve -- which 
> > > has been disabled on my carb and Byrne Heninger's -- there are 
> > > only two moving parts in the entire metering circuit: the throttle 
> > > plates themselves. All metering is accomplished by air flow alone, 
> > > and the amount of fuel that leaves the bowl through the jets in 
> > > response to that air flow.
> > > 
> > > Bill Robertson
> > > #5939
> >
> 
> 
> 
> 
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