Couple of tuning question (Autotune vs diy vs ve analys etc)

[Yves]

I have some questions :

I have the autotune version. If I understood the workings of it correctly it uses the AFR table and sets the VE values so that the AFR target is reached. How accuratly is that actually. I'm under the impression that it sometimes doesn't get it right. I had this type of problem on the lower kPa zones. Does Ve analyser in Megalogviewer do a better job at this or is it better to just do a drive, try to correct things based on the actual AFR's that are in the log ?

[elutionsdesign]

Phil Tobin is the author of both Megalogviewer and Tuner Studio, I wouldn't expect there to be a tremendous difference in how they calculate VE based on a target AFR table. If you solely depend upon VE analysis to build your table you can end up with a very bumpy, lumpy table and if you think about how an engine runs you wouldn't expect a very bumpy, lumpy VE. You have to go back and smooth things out. Accuracy? I think most of us would be happy if the target AFR vs. the actual AFR was within 5%; computers can't predict the future, only react to the recent past.

[Yves]

Phil Tobin is the author of both Megalogviewer and Tuner Studio, I wouldn't expect there to be a tremendous difference in how they calculate VE based on a target AFR table. If you solely depend upon VE analysis to build your table you can end up with a very bumpy, lumpy table and if you think about how an engine runs you wouldn't expect a very bumpy, lumpy VE. You have to go back and smooth things out. Accuracy? I think most of us would be happy if the target AFR vs. the actual AFR was within 5%; computers can't predict the future, only react to the recent past.

Understood, but is it enough to rough in the tables and tune from there ? I was seeing very rich numbers in the lower kPa zones but the autotuner didn't seem to react to it.

[JAM]

if you use the the ve analyse in the log viewer one thing i do is take steady state sections (fixed throttle position, even if this means WOT fixed-no accel enrich) of the log and cut out everything before and after, and analyse that portion of the log and let it correct VE. this has done a very good job of getting my afr targets. seems like the more things affecting the fueling can possibly introduce error (like AE and EGO correction)

[kaeman]

my 2 cents worth. I have found the tuning software to be very good and helpful. I use autotune first when doing a test drive and let it rough in the ve table. then I make data logs while driving and use the ve analyze to make suggestions to my ve table. but in the end, one thing that the software cant do is make up for engine specific peculiarities. my engine when stabbing the throttle adds all kinds of fuel and then the afr shows very lean, which means that its realy getting a rich misfire. so I am taking out fuel from accel enrich and smoothing that section of the ve table myself. because the lean misfire keeps making the tuning and analyzing software add fuel to an already to rich bin in the ve table, when you do your tuning tune specific parts of your ve table and use the filters to just adjust the parts of the table where you need more help and leave the parts of the table that are on target unchanged.
Good luck,