My car is running good and was fully tuned with open loop and tailpipe sniffer on a load bearing dyno.

I do notice my afr jumping around and running a bit rich during idle, cruise, partial throtle....

I was thinking about playing around with the O2 feedback on my aemtuner software. (series 2 aem)

Has anybody had much success with this feature?

 

The O2 feedback works really well in the AEM software, I use it on just about every AEM car that has wideband ran to it.

I usually target around 14.5 for idle (depends on what injectors are being used)

14.7-15.0 for low throttle (-14psig to -8psig) and 2500 rpm+

I usually have it tapering off to around 14.0-13.5 as load increases toward atmospheric and have it disable at around -6psig to -4psig (depending on the setup).

The other thing I usually do is limit how much fuel the O2 feedback can take away or add to the fuel value. This way if the sensor ever goes bad, the car doesn't run crazy lean or crazy rich. This also does require that the fuel map be tuned properly or it won't be enough adjustment to reach your targets in some cases.

The O2 sensor feedback is pretty nice to use to help accommodate for weather changes, etc.

 

Do you have a picture of a traget map I can use to give me an idea?

I just want it for cruise/partial/idle.

Nothing while it's in boost. I hear I can use it to fine tune my fuel map too. Just by looking at how much it's trying to compensate.

 

I use it too. for it to work really well it needs to be tuned as described in the manual, which is pretty hard and unintuitive. the rough calibration from AEM works pretty well but certainly allows more fluctuation than a custom setup.

Whether the O2 calibration is tuned or not you should really use it when you are already comfortable with the map. It is not something that will make a crappy map run perfect.

I also run +/-15%. what 93turbo16 said about not running the leaning adjustment is good advice when you are running a very aggressive map and your O2 calibration is not tuned really well. In my NA case, I have set the target at WOT to be 13.1 AFR which is pretty conservative so having the O2 FB overshoot the leaning isn't that detrimental.

I have also found success with it all the way to redline even though I am using an AEM WB which has a pretty low sampling frequency of ~16hz as compared to more expensive system.

 

it's no more useful in tuning than looking at your logged AFR's.

 

I suppose. But when logging, if I see if adds 6% fuel in a certain cell, I can go and add 6%. Might take some of the guess work out...


When once I find that the map is the best it's going to be, turn teh compensation to 5% or less.

 

There is no guesswork when tuning air fuel ratios. AFR and pulse width have a linear relationship at specific rpm and load.

and "5% or less" wont be enough. simple humidity changes will need more than that.

 

Also,... dont use o2 fb at WOT, o2 sensors are not fast enough to do that for the most part.

I usually give the o2 fb a range of +/- 10% If you need more correction than that the car isnt tuned good enough from the get go.

 

AT 8000 rpms the aem unit reads the AFR every 8 revolutions, which to me seems sufficient enough to use at wot...why do you think they are too slow.

 

I don't plan on using it at WOT. just idle, partial and cruise. Nothing wile boosting at all....