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Hey all,
So I am in the process of planning out a 400whp turbo build for my AP1. I am familiar with mechanical systems of cars, but the ECU is black magic to me. So, I am planning on running 15 psi of boost max. I will need a larger range MAP sensor to account for the extra boost. My question is, how does the ECU know the range of the MAP sensor? They all seem to be 0-5V output. I have used pressure transducers extensively in the past, and I always calibrate them and get a regression formula to convert the voltage out to pressure. Does the tuner have to do something similar with the ECU here? Because if I just go ahead and swap a 3 bar MAP sensor for the standard MAP sensor (which I'm assuming is also 0-5V output), the 5V output of the larger range sensor is going to mean an entirely different pressure than the output of the smaller range sensor.
Any input would be appreciated to help me understand this better.
The sensor comes calibrated. For example it can be calibrated so that 0V=-15PSI 2.5V=0PSI and 5V=15PSi just to illustrate my point. The MAP sensor should come with these 'calibration settings'. You then copy those calibration setting into the ecu so it knows how to interpret the voltage. Most ECU's however aslong as your using a popular MAP Sensor (AEM 3.5 Bar MAP Sensor for example) Will simply have the option of a drop down menu for Map sensor, you simply select it and the ecu plugs everything for you. This is a huge reason why one should use quality and commonly used sensors as they will usually already be an option in the ecu.
The sensor comes calibrated. For example it can be calibrated so that 0V=-15PSI 2.5V=0PSI and 5V=15PSi just to illustrate my point. The MAP sensor should come with these 'calibration settings'. You then copy those calibration setting into the ecu so it knows how to interpret the voltage. Most ECU's however aslong as your using a popular MAP Sensor (AEM 3.5 Bar MAP Sensor for example) Will simply have the option of a drop down menu for Map sensor, you simply select it and the ecu plugs everything for you. This is a huge reason why one should use quality and commonly used sensors as they will usually already be an option in the ecu.
Oh great, that sounds super easy. I'll definitely have to take a look at how the ECU interface is looking. Thanks a bunch for the help! Super excited to get going on this project.
Just had another question, not entirely related to the MAP sensor but has to do with the ECU. I understand what switched power is, makes perfect sense, but what in the world is switched ground? I've been trying to figure out wiring the ECU for awhile, and everything now just about makes sense except for this part. See diagram attached (D11).
That is just a switch wired in series to ground, I don't know for what function but probably something programmable.
Like activating two step, arming NOS or whatever
Got it, thanks for the reply! So it's a physical switch, that when activated, tells the ECU to do a certain function, like as you said NOS or two step? Makes sense to me.
ECU MAP sensor question
