What values get sent to a device that asks for the current MAP value? Is it the unit (0-255) byte in the map scaling table seen in ecuflash after converting from sender voltage? For example, using the 1.x bar stock map and evox/jdm map scaling tables below with a voltage of 2.95V will have a byte value of 48 and 143, respectively. That sound right?

The reason I ask is I bought an aeroforce gauge primarily for digital coolant temps and the two analog in ports, but also to replace a failed sender on an aem boost gauge. With the stock sensor the aeroforce gauge maxed out at 3.6 psi which was expected and with the evox sensor it never seems to hit boost. I assume they have some scaling parameter from the bus value to pressure. The company seems willing to change the scale on my gauge to whatever I want (I suggested a menu with slope-intercept, but that's not an option). The only problem is I'm not quite sure what the scale needs to be. Is it the same as the evoscan formula (psia = x * 0.19347) since they should be reading the same value?

Maybe I can just ask them to use the evox gauge scaling? Not sure if the ecu has the same values on the bus at the same pressures, though.

I could just install another MAP sensor and wire it to one of the analog inputs, but then that adds yet another vacuum line that can fail and more wires to run into the car.

0.84 11
1.37 20
1.89 31
2.42 40
2.95 48
3.48 57
4.00 67
4.53 80
4.98 255

0.51 20
0.90 40
1.29 57
1.68 78
2.07 97
2.46 117
2.85 138
3.24 158
3.63 255

 

Bump. Anyone know?

I may just end up getting another MAP sensor for the gauge and giving up on using OBD data for it.