Guide to VE tuning using fuel trims
The help file in the software is decent and there are stickies like this one that has lots of information. Paper manuals are only good for the day you print them, if something needs to be changed, you may never know or you may forget to insert the update. I write tech manuals for a living, if an engineering change comes through, I need to change the instructions, it could take months to get that to the field on paper so electronic media is your friend.
http://www.hptuners.com/forum/showthread.php?t=4742
http://www.hptuners.com/forum/showthread.php?t=4742
On that note, the help files explain what they tables are. You are buying programming and interfaces to be able to do tuning. When you buy your computer it is the same thing. There is no magical book that comes with it that tell your how to right a 100 page paper for your thermal fluids design class. Let's be real here. It is a tool. There are explanations on the tables which are very helpful. They can not possibly go into the detail on explaining what to change, how to change it, and why to change it. Some cases, there is no one right answer. The forum is only as useful as you make it. If your questions are not getting answered then you either do not have enough info, the right info, or it has been asked so many times that people are just sick of replying with the same answer.
I paste the full value of the STFT histogram at first because the values are (usually) a good ways away from 0 (greater than +/- 5). The second time I use half the value because the STFT's are (again, usually) pretty close to zero, so I want to make a smaller adjustment so I don't overshoot. Using this method, I got very close (STFT's mostly in the +/- 2 range) after the second pass. I actually did more logging and more half value adjustments, but I never really got any closer for my effort.
I have the same question. I did as the sticky said, paste special - add, and it added way to much. For instance, a particular cell was 67, LTFT was 12 STFT was 3, so it added a total of 15 to the 67 to get 82. Logged it again and it was at -5 total. I was like WTF. Started over, and the second time I did a paste special-multiply by %, and the LTFT + STFT of 15 changed the 67 cell to 77, logged again and it was very close. I had some cells that had LTFT+STFT over 20, this made the difference even greater.
Is my thinking flawed? The fuel trims are percentages right? Then why not always multiply by the percentage?
