MAF in open loop?
08-04-2007, 03:17 PM
#1
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MAF in open loop? Real basic noobie question here. How can a MAF tune be used in open loop? I thought the whole idea of using a MAF was to use data from o2 sensors in a closed loop based measure of airflow. Why would one keep the restriction of the MAF if they're gonna use an open loop system? Why not just lose the restriction, sell the MAF, and go to a SD open loop tune?
08-04-2007, 04:38 PM
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Open loop and closed loop are simply a method of feedback to the PCM. Both OL/CL modes have nothing to do with MAF or SD mode airflow/fuel calculation. O2 sensors providing feedback give the PCM data to determine fuel trims, which are simple adders to the original amount of fuel that is calculated for delivery.
It's like going to McD's for a burger (MAF or SD airflow/fueling calculation) then stopping at DQ because the burger wasn't enough (positive fuel trim) OR pulling a Nicole Richie and sticking your finger down your throat (negative fuel trim) before going home (fuel delivery).
They're two totally seperate functions.
It's like going to McD's for a burger (MAF or SD airflow/fueling calculation) then stopping at DQ because the burger wasn't enough (positive fuel trim) OR pulling a Nicole Richie and sticking your finger down your throat (negative fuel trim) before going home (fuel delivery).
They're two totally seperate functions. Last edited by SSpdDmon; 08-04-2007 at 06:36 PM.
08-04-2007, 06:25 PM
#3
OL/CL are control models. OL is a model with NO feedback, CL is a model with feedback.
http://redhardsupra.blogspot.com/200...-2-olvscl.html
MAF/SD/alpha-n are airflow models. they're just different ways of measuring airflow.
http://redhardsupra.blogspot.com/200...on-part-1.html
http://redhardsupra.blogspot.com/200...-2-olvscl.html
MAF/SD/alpha-n are airflow models. they're just different ways of measuring airflow.
http://redhardsupra.blogspot.com/200...on-part-1.html
08-07-2007, 10:09 AM
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thanks, looks like a good write up. I'm kinda touch and go w/ the internet here at work. If you have time send me a like to the "How speed density works" write up, thanks!
