Tuning the boost WGSDuty on a GT30R and noticed the BARO reading doesn't stay constant. It actually decreases as boost and RPM climb. Also noticed Battery voltage drops just a touch.

Omni4Bar is wired into MAP input
ZT2WB is wired into rearO2 (but the sensor is currently dead, so the reading is pinned to 15.3:1)

A few months back I had a no-start condition that turned out to be a poor +5vref connection for the factory MAF.

Maybe I need to rewire the MAF connector (or the +5v line at least)?

tsunari said:

noticed the BARO reading doesn't stay constant. It actually decreases as boost and RPM climb.

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It's practically nothing (the decrease) and it's ok.
Your baro sensor in the MAF measures the "static" air pressure. That static pressure probably would reduce very slightly when airflow is high, because the air is being pulled through there, not pushed through. Especially if you have an air filter on it the static pressure inside the MAF would reduce slightly at high airflow.

tsunari said:

Also noticed Battery voltage drops just a touch.

Click to expand...

That is also practically nothing and it is normal. One cause is increased use of electrical current by the fuel pump as your boost goes up (take a look at the chart for your fuel pump, the amps versus pressure chart). My car drops almost a full volt going from lazy cruise to full-on high boost. Your voltage right at the alternator post might not drop, but there is voltage drop in the wiring that goes from the alternator to the rest of the system.

Here's a log from a 1995 GSX with a 2g MAF and some healthy mods, and he was capturing values for Baro so you can display Baro in the log. His Baro numbers are doing the same thing yours are.
His go down a little more than yours during hard pulls, a little more than 1 inHg. Probably because his airflow is higher, hitting about 43 lbs/min. Your Baro is going down a little less than 1 inHg and your airflow is hitting 31 lbs/min.