Re: MAP calculations?

[rr <RRauscher@nni.com>]

That is very close to what I use for the map A/D counts:

    Kpa = (N * 0.369) + 10.35

One thing to watch with the '747, is that the VE1% table has the axis
reversed from just about everthing else. Here is the .ecu entry that
I've used:

{0x37f, 8, 9, 1, 0, 0.0, 0, 0.390625,VE as % (FL1),
MAP,   20   30   40   50   60   70   80   90  100,
kRPM, .4 .81.21.62.02.42.83.2}

This is all one line, you'll need to hook the three above lines back
together for the .ecu file. It is RPM across the top, with MAP down.

The math I use to change the VE% is:

NewVE% = (((BLM / 128) - 1) * 2)   *  OldVe% + OldVe%

So, if the VE% is currently 40, the new VE% is: 28.8

BobR.


Reid Bishop wrote:

> I'll ask this question once again, having not heard an answer before.
>
> When reading the MAP voltage output on a 7747 ALDL datastream, how does one
> convert it to actual MAP pressure?  The only source I have says this:
>
>         MAP kpa = MAP(AD)/2.706 + 10.3
>
> Is this correct?
>
> Here at 6300 feet, my 4.3 idles at about 37kpa, with the IAC running 38-42.
> I still am showing 110 BLM's at idle, and I am having trouble getting it
> leaned down some more.  I'm just wondering if I am adjusting the correct VE
> cell.
>

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