2-bar MAP snensor

Walter Sherwin wsherwin at idirect.com
Wed Mar 1 02:30:23 GMT 2000


Thanks!  There may indeed be an error in the transform equation shown, but
more than likely the discrepancy arises from me not being very clear when I
made that chart (a long time ago).  I was kinda worried about exactly this,
after I had already posted it.  I'll send an updated copy to Steve R.  in
order to stem future confusion.   The transform equation shown can only
be used to transform MAP2 sensor voltages to MAP1 sensor voltages,
and if you run the numbers you will find it to be correct.  The same
equation cannot be used to transform "counts" to "counts" as portrayed
on the Y-axis.  The Y-axis counts as shown are really only for illustration,
to show how each sensor could be fully scaled across an 8-bit 0-5 A/D
conversion.

I am intrigued by your '730 2 bar setup.  Did you simply substitute a 2 bar
sensor in place of the 1 bar, and then rescale everything that it touched
(ie: VE, spark, AE, EGR, BARO,  dwell, flow, etc)?  Or, did you create a "1
bar representation" of the 2 bar signal, store both to RAM,  and
subsequently use each to drive different functions (ie: use the 2 bar for VE
and spark lookup, and use the 1 bar to drive everything else)?   Have you
had good luck so far?


Walt.




>
>
>| I just uploaded an Excel graph which may also be helpful in this regard.
>| The file is in the new FTP incoming directory under
>| "Map1Map2_Transforms.xls".
>
>I think you may have a math error in the map1 to map2 conversion
>equation.
>
>I have a 2bar sensor now running on my '730 with a patched axxc
>bin. I'll post more details later.
>
>john gwynne










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