E78 Virtual VE scale - What does MAP / Baro (pressure ratio) mean?

[steelmesh]

E78 ECU, tuning a Cruze 1.4T. This unknown scale ranges from 0.30 to 1.66 and it is labeled "MAP / Baro (Pressure Ratio)"

What is this actually measure? Parameter?

[cobaltssoverbooster]

exactly what you typed....its the offset ratio between the map and barometric pressure sensor.
last i remember it was still a custom pid you had to make

[steelmesh]

exactly what you typed....its the offset ratio between the map and barometric pressure sensor.
last i remember it was still a custom pid you had to make

Here is a quick acid test I did in excel, makes sense:


Thank you again cobaltoverbooster!

[Keith@HPTuners]

PRatio is a built in math in VCM Scanner 3.0

[cobaltssoverbooster]

PRatio is a built in math in VCM Scanner 3.0

sweet its been added in...that helps a ton.

[steelmesh]

I tried some built in pressure ratio parameter initially trying to setup a VE table to log. I just tried it using a custom math function, i can see this output by building a gauge for it, it works.

The problem now (and possibly before) is it wont log data points along the pressure scale see below:


here is the setup for this graph table:

[Keith@HPTuners]

I'm not sure when you would want to create your own pressure ratio math, when one is already built in. Try the built in one first.

[steelmesh]

I'm not sure when you would want to create your own pressure ratio math, when one is already built in. Try the built in one first.

I tried it first and it didn't seem to work, so then I created the first post here. I can for sure try it again with the built-in one to be certain!

[steelmesh]

I found two possible Pressure Ratios I am looking for under Engine > Air Flow > Volumetric Efficiency:




But these two are not outputting any data from these parameters:
Where PRatio Math is the one I created using (MAP divided by Baro)




I can't find these Pressure Ratios under the Add Channel, so these can't be added to the Channels List

[ScarabEpic22]

If you assumed MAP = 100kPa, then PRatio = value x MAP (100). So pretty safe to assume that a value of 0.25 PRatio is ~ 25kPa. Not always true if you're referencing the base MAP as some other value than 100 kPa, but it's a good way to roughly estimate what each label means.