Since it took me forever to find this, I'm sharing the info.

There are 2 requirements:

1. Log "Manifold Air Pressure Sensor" as a channel (on the left).
2. Log "Barometric Pressure" as a channel (on the left).




From there, it's simple.

1. In your gauges, charts and histogram, go to the layout of each and add the parameter "Boost[Math]" and set the unit to "psi" and however many decimals you want.








For the histogram specifically, I've got "Boost[Math]" logged against "Engine RPM" and "Cylinder Airmass" (scaled to 1.5).




Gauge

 

Thats pretty cool. A good option for those without HPT Pro. I believe with the Pro, and a boost gauge that has a digital output its much easier. But hell, with this histo, its free.

 

I would rather have it based off of MAP anyway then a gauge input. I've gotten so used to reading Kpa that it all I use with mine.

 

Good info.

 

Thanks for sharing, the new scanner is a learning curve. It has a lot more stuff in it. I actually want to log baro now that you post this. Does it seem pretty accurate?

 

When I added the baro channel yesterday and keyed on, it said 14.6psi.

 

A better way would be to just subtract atmospheric pressure from your MAP sensor. I know for a fact the 99-07 gas trucks dont have a baro sensor (just a MAP), not sure about the diesels. If the baro value defaults to 14.6, which is sea level, it will only be accurate if you are at sea level. At 6000ft altitude ambient pressure is around 12psi.

The MAP sensors read absolute pressure anyway, so 10psi of boost will read 24.6psi on the gauge. If you know your ambient pressure, just subtract ambient pressure the MAP sensor.

 

I tried. No matter what I did, it would not display anything but absolute + boost.

This way works (for me anyway).

 

I thought I sent you that math parameter?

Its simply: MAP(in PSI) - 14.6 (or whatever your ambient pressure is based on your altitude).

Less than 0 means there is vacuum in the intake.

 

Doesn't work in the 3.x scanner. Tried many times.