Mystery MAP Data - Solstice GXP

[Jack B]

I have several logs of wot runs from my Solstice GXP and there seems to something that needs an explanation. Here are the details:

1.The car has a MAP sensor in the intake manifold and a boost sensor in front of the throttle body.

a. The map sensor reads psi in whole numbers and the boost sensor has an accuracy of two decimal places, therefore, a comparison can be off by 0.5 psi.

I do understand what absolute readings are, but, I cannot explain the following numbers. Here are the issues and actual numbers from a recent run using the HP Tuners scanner:

2. The boost sensor read 19.73.

3. At the same time the Map read 27 psi, therefore, a difference of 7.27 psi.

What is also interesting is that the boost gauge in the car is driven off of the MAP sensor, yet, it correlates (magnitude) with the boost sensor, not the MAP sensor. That has been verified by removing the the map (still wired) sensor and manually pressurizing a vessel with it installed.

Anyone have any ideas of where the 7 psi diff comes from?

[Baldturbofreak.com]

Something to do with the BARO reading?
Absolute-BAro = guage pressure?

Jsut tossig things out there.

[Jack B]

Something to do with the BARO reading?
Absolute-BAro = guage pressure?

Just tossing things out there.

At your hp, these numbers should bother you the most, which number are you using for your tune. Use some of those connection and play Sherlock.

[Baldturbofreak.com]

Logging in psi,viewing in kpa?
With my config I havent really seen any of that, I wasnt even aware we could monitor the boost sensor. Im going to look it over right now.

[Baldturbofreak.com]

I couldnt find the boost sensor. Here's my config file.

[Jack B]

I couldnt find the boost sensor. Here's my config file.

BTF:

I'm using a custom pid, the boost is KPA converted to psi, minus 14.5. That makes it even stranger. I can tell you this my custom pid in HPTuners gives the same result as the DashHawk, which, has the boost sensor built into the firmware.

[Baldturbofreak.com]

oh I thought you were loggin the T-map somehow. Actually that would be quite easy, jsut tap the purple wire and run it to one of the a/d's on the side of the HPbox.