So I am new to Evo's and have been seeing that in order to log boost, the JDM or Evo X 3 Bar MAP sensor is needed. I get that part! My question is, WHY? Or even more so HOW does it make sense for the ECU to not know boost pressure?

Doing searches, all I can find is what needs to be done in order to log boost, which is great stuff and will be performing the sensor swap soon on mine. I guess I like to have a better understanding of why things work, which helps me in the how department when it comes to vehicle systems.

Sorry if there is already info out there on this, I just didn't see anything. So if there is some info that I missed, please don't kill me!! Lol

Thanks for the input!

 

the ecu in stock form uses calculated load instead of a direct measurement of manifold pressure. It calculates that load based on several different sensor readings and variables.

 

That's kinda what I figured. Any idea what sensors it uses to collect that data?

 

been wondering the same thing actually. But i just figure the computer still knows exactly how much air is being consumed anyways by the maf sensor so i guess it really doesnt absolutly need to know exactly what the boost is since it still knows how much air is going in.

 

It has a mass air flow sensor. It knows how much air is going in. It doesn't need to know boost pressure.

 

Yup. The factory boost control implementation controls load and not boost pressure, so should really be called load control and not boost control.