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Re: Question about WOT table in $8D bin
There are "Real Time" AFR devices which display the actual result , unfortunate
though , not affordable for DIY projects. These sorts of devices are most
helpful
in WOT conditions , when O2 responses are ignored and controller uses fixed
table lookup for the AFR values. For instance ,Exxon - Mobils' lab can look
inside
the chamber , record infrared and combustion pressure curves , still ,
they don't
have all the answers. Consider the Fuel component itself as being a BIG
variable.
If you line up 10 of the same engine profile , each has its own slightly
different
personality, which the factory compensates for with compromise built in to
the
control routines. One such compromise is running a bit fat @ WOT to suppress
detonation and make the engine live longer , cutting warranty costs and makes
the "average" vehicle owner happy with the increased longevity and less out
of pocket maintenance $. Factories don't build em for us to race.
When we jack in more fuel and spark , they may run faster , usually they
don't live as long , there's always a price to pay watching the rev counter
continually fly by 6000. Anyone who tells us it costs no more to spin to 7000
is just blowing smoke. The faster you go the more it costs, of which there's
NO doubt in my mind. Many times we think what something is supposed to be,
later we find that it's not, especially in the interpretation of E- PCM
generated
data responses that aren't real time data.
Len
I know computers don't "guess" anything that's why I put the word in quotes.
As far as I know the ECM has no idea what the actual AFR is in the
combustion chambers so it calculates it based on what info is in the EPROM
and displays it as such. That's what it's supposed to be, but what it
actually is... is another story.
----- Original Message -----
From: "Len Sabatine" <sabatine@epix.net>
To: <gmecm@diy-efi.org>
Sent: Wednesday, November 15, 2000 2:26 PM
Subject: Re: Question about WOT table in $8D bin
> Humans make "guesstimate"[s]. ECM s' respond to what information
they
> gather from sensor inputs and adjust operating parameters to the best
set
> of circumstances possible at that point in time. The adjustment [s] go
> as far
> as the default values in place. They're constantly working to drive
the
> fuel
> values to stoich, from there it's truth or consequences. Data stream
parms
> are a good barometer of conditions , unfortunately what we see is
after the
> fact. Reading spark plugs tells it like it is in the combustion
chamber.
> Len
>
> >It is.... But as far as I know it's only a "guesstimate" on the ECM's
part
> >? :)
> >
> >
> >----- Original Message -----
> >From: <rrauscher@nni.com>
> >To: <gmecm@diy-efi.org>
> >Sent: Wednesday, November 15, 2000 9:38 AM
> >Subject: Re: Question about WOT table in $8D bin
> >
> >
> > >
> > > The end result AFR should be available through the aldl stream.
> > >
> > > BobR.
> > >
> > > >
> > > >
> > > >>Just remember you said that <g>
> > > >
> > > >I'll remember Bruce <g>. But, I'm not a fluke. I've talked to
several
> > > >other AFR190/MiniRam ownders that are running the same type of spark
> >advance
> > >
> > > >(max). Now sure about the Air/Fuel ratio they are running though.
Will
> > > >be pulling plugs soon to take a gander.
> > > >
> > > >Curious though .... I have a feeling that you think I'm gonna blow
myself
> > >
> > > >up :-) Can I pick your mind and ask why? I know that I will
eventually
> > > >lose the bottom end ... but, I don't think that it will be PROM
related.
> > > >
> > > >Tim
> > > >--Hushpart_boundary_eYvmZstygnGXAipUacYxZzmLZmTFfPtA--
> >
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> > >
> >
>
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