Technical question on O2 sensors

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Oct 6, 2011 | 09:37 AM

#41

fuelmoto

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Joined: Feb 2007

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From: Little Chute, WI

Quote:

Originally Posted by rowle

Did anyone answer the questions of;

The 2012 motors have wide band o2 sensors ??????

If so, whats all that gonna give us ?

Thanks all.
Rowle - UK

2012 bikes do not have wideband sensors

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Oct 6, 2011 | 09:51 AM

#42

fabrik8r

Outstanding HDF Member

Joined: Jan 2010

Posts: 2,916

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From: earth

Quote:

Originally Posted by fuelmoto

A simple answer is that the Delphi system delivers fuel based on "modeled" airflow not "measured" airflow, the O2 sensors are simply used as a control to keep the mixture at (or near) stoich 14.68:1 AFR. When in closed loop the O2 integrator adjusts the mixture based on O2 feedback as a short term fuel trim, if necessary it will also store a long term trim AFV/AFF for a certain block learn area. The problem with the system adjusting for a different exhaust/intake is not only is there a specific window of adjustment, but also the further you get from the actual airflow model in the calibration (in this case the VE table) the less accurate the fuel control is

Key point here: HD EFI is not a MAF system, it is akin to the early generation automobile air speed density EFI systems and it has limitations. Even if it were a MAF system, it would compensate better but it still would not self tune, the O2 sensors still only assist fuel regulation in the "cruise range", the way the engine breathes outside the cruise range requires manual adjustment of the base map to bring the AFR results back to a desireble result; this requires real time WB O2 sensors feedback which are typically incorporated into dymo tuning operations. Changing pipes and air cleaners doesn't simply change the amount of air that moves through the engine but also changes volumetric efficiencey, or the amount of air at a given RPM. Its not as simple as adding a fixed 10% air with pipes and a cleaner and then adding 10% more fuel across the board. For a proper tune the fuel must be ajusted manually across the map to accomodate the new volumetric efficiency requirements, via realtime AFR feedback and/or real time HP/TQ feed back AKA Dyno, and this my friends is absolutely not "unadulterated, 100% pure, undiluted Bull S*** also known as Pseudoscience".