Data Logs Stock vs Aftermarket intake

[markmurfie]

I run 11.0s at 124-125 with 43-46 on my datalogs . The tune ignores the maf at WOT . I can make it show 3lbs/min or 70lbs/min and my fuel trims will still be zero . The only time it will matter is if you change something else that allows the airflow to increase using the same maf period table .

It also ignores the O2 sensors at WOT. This is because it goes to open loop mode at WOT. It depends absolutely on the MAF table in open loop mode. Open loop is ecu tables. Closed loop is sensor information. The MAF basically maintains a wire at a constant temperature using varying frequency. In closed loop the ecu can see the error in your table and compensate for it. In open loop the ecu ignores the sensor and goes completely off the table. This is where the difference in your actual and commanded lambda comes in. The difference between these is your open loop fuel trims. Factoring them in is essential because your MAF is inferred from a table in the ecu not coming from the sensor directly. What throws some reading off at wot is the cat over temp protection as that is a closed loop mode.

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