[BDPhoto519]

I recently installed a set of TSP 2" LT headers w/cat deletes on my 2018 SS and I am starting to work on the tune.

I am noticing the STFT & LTFT are slow/chasing each other a lot at idle and low rpm. I saw a thread awhile ago on here mentioning you need to adjust your tune for the furthur distance back the o2 sensors are now located with the LT due to delay and cooler temperature but I searched everywhere and can't find it again.

Does anyone have some suggestions for dialing this in? I see there is several tables like the "o2 threshold table"

Thanks

[easttxss]

Have you tried resetting the LTFT?

[BDPhoto519]

Originally Posted by easttxss

Have you tried resetting the LTFT?

Yes, thanks I have reset them in HP Tuners every time when I make some fueling changes.

Everything is working fine I just noticed the response times are delayed and somewhat hang compared to before I put the headers in and I have saw countless threads suggesting a common change after headers is to correct for the delay in the tune.

I am going to try and find the big thread on it again today, maybe it was on HP Tuners. I will update this thread if I find it.

[BDPhoto519]

Well I managed to find the thread with the really informative discussion on the topic, it was on the HPTuners forum.

I posted the link below for anyone interested in the topic as well.

https://forum.hptuners.com/showthrea...nsport%20delay

[6spdhyperblue]

I have played with the settings in that thread and they can be improved slightly. While the o2 sensors are further downstream the larger primaries likely reduces velocity. What does all this mean in terms of when the pulse reaches the sensor? IMO they aren’t that far off and less is more.

[BDPhoto519]

Originally Posted by 6spdhyperblue

I have played with the settings in that thread and they can be improved slightly. While the o2 sensors are further downstream the larger primaries likely reduces velocity. What does all this mean in terms of when the pulse reaches the sensor? IMO they aren’t that far off and less is more.

Thanks, I opted to leave them at stock values for now.

The STFT seem to oscillate abit slower then stock and they seem to not adjust anything when the LTFT are +/- 5%-ish. I am fine with that for now.

I am installing my WB this weekend, so I am hoping my NB stoich reads close to my WB stoich. If not I may have to revisit this.

Thanks.

[6spdhyperblue]

No problem there’s only so much you can do without the cats there to stabilize the temp

[BDPhoto519]

I ended up trying a suggestion of -10% to the entire P table, and +15% to the entire I table. I can say it definitely made a noticeable difference in the stability of the WB swings back and forth +/- from 1.000 lambda. (0.6/0.6 before to 0.25/0.25 after at idle)

I am sure some fine tuning could be done from there, but probably just splitting hairs. Only reason I played with it some more was because I was stuck in traffic watching the WB display oscillate back and forth one day and it was bugging me. =P

[jasonz28camaro]

I had a similar issue with mine. The LT and ST fuel trims were good at moderate - WOT but were all over the place at idle and light throttle. I tuned the MAF and MAP accordingly with my wideband but could not get it where I wanted. I ended up doing a narrowband tune and ignored the wideband to adjust the idle and light throttle and it made a world of difference. For some reason no matter what I did with the wideband the tune did not like the adjustments.
Goatropegarage on youtube has a video on narrowband tuning that I used to get the car ready for logging. I only used this for the idle and light throttle, my wideband was used for everything else.