I decided to fine tune my ignition map based on the boost levels so I wanted to make sure the GM 3 bar maping scaling was good. Once I charted the logged PIM against advanced PIM V values and compared the line to the DL programmed scaling of 6525, offset 0, there is a fixed difference between the scaling program and the log results.

I have attached a chart of the scaling program vs actual log values for PIM and PIM V. I can't understand why there is a fixed difference. I want to use the DL readings to determine boost and tune IGL.

My two questions are:

1 What is the reason there is a difference between the log and progamming?
2. Without having to calibrate the 3 bar sensor is the formula V*8.94-14.53 adequate enough for determining the boost level from the DL?

 

Okay..I think I figured out why but can't believe I had this wrong all this time. I was using a linear formula of V*6300+800, which is what I calibrated the map sensor to over two years ago. I entered the scaling as 6300 and offset as 800, but is seems the pfc subtracts the offset so it has been running at V*6300-800.

I don't want to change my scaling becasue the AFR's are pretty good and the car runs well. I just need figure out what the correct boost levels are and adjusted my ignition tuning.

 

sometimes you just have to work around things like MAP sensor scaling because it's too much trouble to retune. I have the fuel and timing on my friend's FD built around the incorrect factory scaling.