tuning o2s with headers closed loop
08-17-2016, 07:26 PM
#1
tuning o2s with headers closed loop I've done all the basics and I have a solid running LS1 with a TSP 228R cam and mid length headers.
-BRAF
-MAF tune
-VE
-Idle
Then recently went back over MAF and VE. Have them looking great with the wideband. Following this I put the car back into closed loop and started working on the O2s. Back in CL i'm running a bit lean, maybe 15.4 to 15.3. Computer is trimming fuel out. (this is all part throttle stuff.. no WOT stuff yet). So I read up a bit and decided to try adjusting the integrator delay. Made a 12% change for more delay, didn't see a change. Then came across o2 switch points and so I did a log in open loop and have a histogram of the o2 values when my wideband says 14.7. I adjusted the switch points upwards in the airflow modes that were effected and achieved the desired AFR in closed loop. Now back in closed loop my O2s are switching well in airflow modes below 14, with 14 being a little iffy and in mode 16 they switch but only slightly, just kind of bouncing around the set switch point by about 50-100mv. No driveability issues or problems, I was just under the impression that the O2s should switch more drastically for optimal closed loop performance.
So right now I need some direction..
1. should I continue trying to tune the o2s so they oscillate more? if so, why? I have the o2 DTCs turned off, no cats and no emissions to worry about.
2. I've read that the closed loop proportional vs airflow and integrator may be the way to get the o2s to agree with the wideband when the o2s have been moved (headers). Should I put the switchpoints back towards stock and work on those instead?
3. Or leave the switchpoints and integrator and try adjusting the proportional for the airflow modes where o2 switching is less than desired?
My thinking with the switchpoints was this... if in open loop you have your AFR dialed in at 14.7 and the o2s read 600mv then with the current engine setup 600mv would seem to be where the switchpoints need to be regardless of closed loop proportional or integrator settings, right? or am I missing something?
wideband is a innovate LC-2 verified the reading from the unit with the HP tuners before I started tuning.
Thanks.
-BRAF
-MAF tune
-VE
-Idle
Then recently went back over MAF and VE. Have them looking great with the wideband. Following this I put the car back into closed loop and started working on the O2s. Back in CL i'm running a bit lean, maybe 15.4 to 15.3. Computer is trimming fuel out. (this is all part throttle stuff.. no WOT stuff yet). So I read up a bit and decided to try adjusting the integrator delay. Made a 12% change for more delay, didn't see a change. Then came across o2 switch points and so I did a log in open loop and have a histogram of the o2 values when my wideband says 14.7. I adjusted the switch points upwards in the airflow modes that were effected and achieved the desired AFR in closed loop. Now back in closed loop my O2s are switching well in airflow modes below 14, with 14 being a little iffy and in mode 16 they switch but only slightly, just kind of bouncing around the set switch point by about 50-100mv. No driveability issues or problems, I was just under the impression that the O2s should switch more drastically for optimal closed loop performance.
So right now I need some direction..
1. should I continue trying to tune the o2s so they oscillate more? if so, why? I have the o2 DTCs turned off, no cats and no emissions to worry about.
2. I've read that the closed loop proportional vs airflow and integrator may be the way to get the o2s to agree with the wideband when the o2s have been moved (headers). Should I put the switchpoints back towards stock and work on those instead?
3. Or leave the switchpoints and integrator and try adjusting the proportional for the airflow modes where o2 switching is less than desired?
My thinking with the switchpoints was this... if in open loop you have your AFR dialed in at 14.7 and the o2s read 600mv then with the current engine setup 600mv would seem to be where the switchpoints need to be regardless of closed loop proportional or integrator settings, right? or am I missing something?
wideband is a innovate LC-2 verified the reading from the unit with the HP tuners before I started tuning.
Thanks.
