Question about WOT table in $8D bin

[Greg Westphal]

I thought of something today that got me wondering about the accuracy in
this formula.  It's assuming that the volumetric efficiency of the
engine is the same throughout the rpm range, and that one engine has the
same V.E. as another.  Since neither of these is the case, then it's
only a guess at the AFR.  Shoot, I just thought of a counter-argument. 
The computer -does- know the amount of air being ingested at WOT (and
everywhere else too), so it adjusts the pulse widths to reflect the
additional air a better-breathing engine is inhaling.  Since it's
starting with a "base" (stoich) ratio of 14.7 and then changing the fuel
part to make it run richer, it'll be able to give you whatever AFR one
commands the computer to give, w/in a certain accuracy of course. 
However, as Master Bruce always says, "you gotta give what the engine
wants", and the only way to know is by "listening" to it.  Reading
plugs, comparing trap speeds, etc. all goes hand-in-hand with checking
things out with a scan tool.

Just MHO,

Greg

Len Sabatine wrote:
> 
>     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 at nni.com>
> >To: <gmecm at 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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