I've been searching this subject for a few days now, but couldn't find anything on it. Hopefully it hasn't been right beneath my nose.

I've asked this in other threads as well, but never got a definite answer. I'm just trying to understand how the ECU determines the load. Anyone know the calculation taking place?

 

Load is airflow per engine revolution.

 

What unit does it use for airflow?

 

Some people say that the units are in kPa, but I've never seen anyone do a formal analysis of the code to prove it.

 

I always thought it was a combo of MAF & MAP readings.

 

Its only MAF.

 

So the load numbers directly correspond to these calculations?

 

Do you know if the ECU is using the MAF values to determine the amount of fuel to achieve the desired A/F ratio, or is it using the map sensor?

 

On the Evo 1-9, its only MAF to determine airflow for normal conditions. The JDM Evo 9 will use its 3 bar MAP to determine airflow in a limp home situation, e.g., intercooler pipe blows off or MAF sensor dies. For the Evo X, its likely the same as the JDM Evo 9, but this is TBD.

 

That bring up a quick question: what are the specs of the USDM map sensor?

 

The USDM Evo X MAP sensor is a 3 bar unit. Its the exact same sensor that's on the JDM Evo 9 and X. USDM Evo 8/9 have a 1 bar MAP sensor.

 

Mychailo, are you working on the IDA I sent you or you generated another using the USDM ROM ??

If you're using mine .. pm me your email and I'll send you my updated IDA .. its not the 5268

 

If it uses the MAF, then under normal conditions, what is the MAP used for? I'm trying to get a better understanding of the implementation of it's systems.

 

I decided to start from a USDM GSR ROM. I thought there might be enough similarity to a USDM Evo 9 algorithms to improve the rate of comprehension of the Evo X code. So far, I think its paying off.

Besides the limp home feature likely now implemented on USDM Evo Xs, the MAP sensor is used to judge (not control) EGR system performance. On the Evo 8/9, judging EGR system performance was the only purpose of the 1 bar MAP sensor.

 

I'm not trying to get into a product discussion/argument, but since the ZChip modifies the MAP signal to change performance, wouldn't that mean the MAP sensor must be doing more than what you described?