PSIG wrote: ↑
Wed Mar 18, 2020 8:57 pm
BK, I am not raining on your parade, but I am trying to understand what you are saying or stating. So, let me make a few comments, and then you can rephrase your responses so I "get it".
You will never offend me if I am learning from you. Rain away.
David, thank you as always.
Your timing of involvement is perfect.
Your comment about helping you to “get it” is exactly what I’m hoping you can help me to do - “get it.”
Just so you and everyone else are aware, I am only into tuning for 4 months now so in many ways I am still a beginner. The only thing I am doing that might be unique is I want to understand how each of the aspects of base tune work and interact. So I slowed myself down and tested the extremes of each one of the aspects of base tune. I have lots of tests done and lots of data starting to show results as in getting good tunes.
I need your help to make sense of all these tests to try to understand why they work. I’ve done the tests and experiments and know that they do work, but I don’t know that I have the background or the right wording and technical descriptions to have it make sense to the ECU community.
Help me validate or debunk this data and then help me find a way to communicate it so that everyone else can understand what I am doing.
You asked me to explain what table tipping is. I would like to find a better wording for that and I’m sure you’ll have a good answer.
Tipping, there are two aspects to it.
There are two things that get changed with this tipping idea.
One is, you will see that the table is flatter and smoother so it visually has less big peaks and much less deep valleys as is shown in one of the pics I have attached called “bad voltage and dead time” and you can compare this to the pic called “good tune” which is much smoother. Also these peaks and valleys are telling you that it is tuning erratically, i.e., the O2 sensor gauge swings wildly and never settles down to a targeted AFR.
The second one is, working with voltage and dead time you can change the actual VE value numbers as described next. This enables you to elevate the idle area for easier tuning.
Originally I had a value of 12 in the idle cell and my peak load area I had 180 as my largest cell value. Then I changed the voltage from 13.9v to 14.8v and I noticed that my idle value after tuning was now 34 which is a gain of 22. In the high load area it became 189, which is a gain of 9. So the idle circuit had more improvement from voltage than the peak load area. A gain of 22 at idle made low end tuning a lot easier and the 9 I gained at top end was not so large that I couldn’t then elevate the entire table. This then enabled me to add a percentage to the entire VE table and add the same percentage to required fuel/Ccs to end up with idle numbers of 42 and peak load numbers safely below 255. So I went from 12 at idle to 42. Tuning better in the whole bottom end. You will need to do another tune as these changes are not real accurate to the original tune.
Dead time has a similar effect. If you think about it, you can fool the dead time a little bit, one to two tenths off of best dead time is about it. But with voltage there is almost no limit. Changing your dead time corrects your fuel load around the dead time issue, but changing voltage looks like it is actually reducing dead time.
So there are two ways the table changes. One visually smooths out the table as shown in my “good tune” VE picture. And the other way the table changes is with voltage and dead time as described above so you can create higher numbers at low end which helps the low end tune better.
I could use some help here, David. I got the data, but I’m not absolutely sure what it is doing here.
And regarding leaving room for AE and Warmup, again I need your help.
Correct me if I’m wrong, that neither AE nor Warmup change any value on the VE table. Aren’t they supplementary fuel outside the normal VE tuning? If that’s true, then they are not part of the concern of the VE table 255 limit. But if you are concerned about running out of injector flow, that is always a concern. Please advise me, I am still learning.
There is also a third picture here that is called “lambda delay” and it shows a strange peak in the upper left area that represents a delay number that is too large. Over on the right side you will see a depression in the VE table, that indicates that the lambda delay number is too small. I have a fast, crude setup for finding lambda delay that I do early on in my base tune, but as you can see, as your base tune and VE table get better you will also be able to see more clearly the lambda delay faults. Just another bonus.
The “good tune” VE table is a result of auto tune on TS with no manual tune changes. The other two tables were recreated on purpose for demo purposes here.
I’m tired of typing and I’ll bet you’re tired of reading so we both need a break for now.
Any and all help is appreciated.