O2 sensor distance/timing

[KonigWolf]

2010 Camaro SS Automatic L99 E38. Car has JLT cold air intake, and Texas Speed Performance 2" Long tube headers. I'm needing to know what/which setting to change to correct new O2 sensor location. I have a WEGO wideand that came with my HPtuners package, an its reading isn't what I have the tune commanding.

I've searched and read several different post, an now I'm just confused. Not sure if the post I've been reading are too old and the terms used aren't the same as the lastest version of HPtuners or what.


hptuners.com/forum/showthread.php?43507-Tune-changes-when-adding-long-tubes

hptuners.com/forum/showthread.php?43693-2008-C6-Z06-E38-Closed-loop-integrator-delay/page2




#1 [ECM] 12480 - Closed Loop Proportional Base vs. Airflow Mode: This table returns the base proportional % fuel change. Proportional base rate table is the primary amount of fuel needed to drive the closed loop fuel control into oscillation. Proportional fuel acts like an on/off switch to keep the fuel moving around the current O2 Rich/Lean vs. Mode table set point. The values on the Proportional Table add or subtract to the base fuel rate depending on the previous fuel condition (i.e. if rich then switch lean, if lean the switch rich). The amount of fuel to add or subtract increases with the airflow mode and should be based on injector size and % fuel switching needed.

#2 [ECM] 12481 - Closed Loop Proportional Gain vs. O2 Error: This table returns a multiplier value for the increase/decrease of the base rate table. A multiplier value of 1.000 will have no effect on the proportional base rate. If the difference between the current O2 reading and its desired value from table O2 Rich/Lean vs. Mode (the current Fast O2 error) is large the VCM will need to change the proportional fuel a lot. If the error is small, it should change it only a little to continue oscillation without undershoot or overshoot. Undershooting will cause the Closed loop fuel to become sluggish or miss the current O2 Rich/Lean vs. Mode table set point. Overshooting with cause the engine to vary excessively in RPM.

#3 [ECM] 12470 - Closed Loop Integrator Delay vs. Airflow Mode: This table returns the base integrator delay. The integrator is a function of the Slow Filtered O2 Error over time, The integrator handles persistent rich or lean fuel conditions based on the slow O2 error and Rich/Lean vs. Airflow mode. The Base Delay vs. Airflow Mode table is the minimum time in milliseconds an overly rich or lean condition needs to exist before the VCM is allowed to make a fuel correction.

#4 [ECM] 12466 - Closed Loop Mode vs. Airflow: This table defines the Airflow mode the Closed Loop routines use to operate. It controls selection of various gains and delays used to interpret the O2 sensor signals.



What do I change.png

[GHuggins]

Closed Loop Proportional Base vs. Airflow Mode - Not only controls how much fuel is added, but also how quickly your O2's switch - In other words how quickly fuel will be added or taken away

Integrator Delay - Time or "period of time" that is required for the exhaust pulse to get to the O2 sensor

More importantly is the one you left off - Closed Loop Proportional Limit - Lowering this will help to control the amount of fuel that is added and taken away to promote O2 oscillations

Everything affects these settings - not just the addition of headers which is why there is no set specific numbers to edit these tables by... For example if a blower is added - the exhaust is flowing through the pipes at a higher velocity, so even though you may have added headers as well - stock settings or even lower than stock settings may be better... Cam added - slower exhaust flow at lower engine loads and rpms, but higher at higher rpms and loads... Headers alone - Are the O2's anywhere near where they were originally? Are the pipe diameters larger to slow down exhaust flow?

Typically with just headers you can lower proportional base airflow by 5 or 10 %, increase integrator delay airflow by 20 or 30 % and then reduce proportional limit down to 1.25 or so to clean up drivability... This is also if the O2's are half again or double further downstream than they were - like I said - everything effects these settings and will require you to log MAF airflow and either increase or decrease specific portions of these tables...

[StopGap]

I very much appreciate this GHuggins and want to say thanks.

I am considering long tubes on my 09 Corvette with an A&A Si trim. As a tuner student, I've anticipated there will be a timing issue reading my DLs once the O2 and WB sensors get pushed so far downstream from the actual combustion event. This question and response has been very helpful if/when I go the long tube route.

[anniversaryss]

I have larger cam and headers. Which would be the best of these tables to modify.
Also the integrator delay, would u be increasing the amount of delay time to slow it down bc the 02s are further away or decrease the delay to to react quicker?