Intercooler/o2 volts/Injector constant

nacelp nacelp at bright.net
Sat May 6 22:05:47 GMT 2000


Diacom itself has an error in it's reported O2 voltage.

> Are you saying that the same 980mV on the Oxy sensor (or Diacom's report
of
> it) equaled 11.5 *and* 12.4 on the WB (on 2 runs)?  Good to know the
> relative numbers are this close, even though the absolute AFR values
aren't
> gettable.

That ain't even close, IMHO.

> At 10:11 PM 05/05/2000 -0700, you wrote:

> >What I found was that, on the Sy we were testing,
> >the actual o2 volts measured by the Datalogger were
> >.192 lower than the Diacom o2. Not sure what the
> >reasons for this are, but I suspect it has to do
> >with the reference voltage of the A/D and the
> >formula used to calculate o2 volts from the scan
> >data.

The error I mentioned above isn't quite that great.

> >What I also found (from actual data compared to an
> >NTK wide-band o2) was that the o2 voltage was not
> >repeatable on this vehicle. 980 mV during one
> >engine run session was 11.5:1 AFR, the next time
> >we ran it (on the same day, same temp condtions)
> >it was 12.4:1 AFR. There was no way you could
> >guarantee what AFR a particular Diacom voltage
> >indicated, even on the same vehicle during the same
> >day.

Yep.

> >What I *did* find interesting was that the trend
> >of the Diacom o2 voltage at WOT followed the NTK
> >wide-band data exactly. The indicated range, however,
> >is very small- you need to export the Diacom data to
> >Excel and graph the o2 data from 700mV to 1v or so.
> >The peaks and valleys show up quite readily, and
> >can be used to show lean/rich spots in a particular
> >cal. That-is, lean or rich relative to other points
> >in the run, since you don't really know for sure
> >where your max power AFR is.

relative, yes, but that's all.
I'll chill
Grumoy
> >Later,
> >
> >Dig
>
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