A definition:
In the mathematical field of numerical analysis, interpolation is a method of constructing new data points within the range of a discrete set of known data points.
In engineering and science, one often has a number of data points, obtained by sampling or experimentation, which represent the values of a function for a limited number of values of the independent variable. It is often required to interpolate (i.e. estimate) the value of that function for an intermediate value of the independent variable. This may be achieved by curve fitting or regression analysis.
A different problem which is closely related to interpolation is the approximation of a complicated function by a simple function. Suppose the formula for some given function is known, but too complex to evaluate efficiently. A few known data points from the original function can be used to create an interpolation based on a simpler function. Of course, when a simple function is used to estimate data points from the original, interpolation errors are usually present; however, depending on the problem domain and the interpolation method used, the gain in simplicity may be of greater value than the resultant loss in accuracy.

 

I look at the map first to see if there are any peaks or valleys that do not look right. After I get that rough smoothed, I do one smoothing operation to finalize it.

I do it for two reasons. I have that type of personality and I was convinced that I was getting knock indicators in the valleys of the map. So I filled in the valleys and smoothed the map.

I also turned off the closed loop learning so that the valleys would not reappear with the closed loop adjustment.

 

Interesting approach. Have you run the map without turning the switch off? I'm just wondering how long it took for the map to have the valleys reappear. And, if you copied that map from the ECM to see how drastic the change was. I might have to do this experiment myself before my riding season ends for the year.

 

Not exactly...I came to this conclusion/approach by loading the smoothed map. Then doing a few log runs and looking at how the VEs changed with the tuning on the smoothed map. The valleys reappeared right away. The more runs I made, the deeper the valley. They would stabilize in about three, thirty minute runs.

The difference approaches 6 percent at 3000 RPM from for the entire map range.

You can also verify this by setting the CLI/AFF on the gage display. When it stabilizes, that means that the valleys have been returned to the VE map.

If the ECU reads not only the exact cell it is in but those adjacent, my conclusion was that the peaks and valleys from the Closed Loop was confusing the EFI.

And if a slightly rich VE is not much different than running a richer AFR, there is no harm done. There must be something with my SE255 cams at 3000 RPM that is giving a resonance wave back through the system. I still have a stone stock exhaust system.

Again, there are some real leaps made here. Bottom line is that it runs really well. About 43 MPG, riding double with a week's worth of gear attached.

I also smoothed the AFR table. I did not like the look of the stair steps that you get on the map. You do not have to smooth the entire table. I just smoothed a row on either side where I changed the AFR and smoothed just that area.

I also have concluded that you should not smooth the spark tables. It raises the lows too much and reduces the highs too much.

Concerning the spark tables...one thing that I am doing now that I have locked in the VE/AFR is to find where the knock events occur.

You can use the log files to find the knock events but it will not tell you where you can increase the spark. If you tune out the knock events and then increase the spark across the board and continue to tune out the knock, you will find where the ignition map will take more advance. That is easy to do with the quick tune/spark in the tuner. Just add spark either across the board or in a specific range. I prefer the medium load...that is where I run the most.

The quick tune is my favorite feature. On our trip this summer, I just reduced the fuel (increased the AFR) by one percent and got better fuel mileage. You can also modify by fuel and spark for those really hot days right there on the screen. Previously, I had four alternate maps with richer AFR settings and less spark advance. You can now use your base map and adjust at your leisure. Have fun.

 

My rear VE has a valley at 3000 and 2000 rpms.
My front VE has a valley at 2000 and 2250 rpms.

Makes sense to me, think I'll try this.

 

If you are getting larger peaks or valley's in you calibration below 60Kpa you may want to try the Charge Dilution Effect tables to smooth/flatten them out. If your calibration does not have these tables exposed simply run the update client and load the newest PV firmware (also update the tune database as well) open up WinPv, load your map and go to Power Vision>Update Tune from PV and it will expose all of the newest tables.

 

As this is new territory for many of us, are there any guides on how to properly use/set these tables?

 

I have looked at this table and don't have a clue how to use it or what the values mean. But, let's say that I increase the 1875 and 2250 areas by 50, and do a autotune run, what can I expect to see happen to the appropriate VE table in those areas <= 60kpa?

There is no documentation for any of the new tables at this point.

 

For the life of me I can't figure out how to do a data log run the old way now (where you enter 319245) that I've updated to autotune. I see where I can enter the code, but I can't seem to get the logs to the Log Tuner software. It saves them as pvv files, while the Log Tuner software is looking for stk's (I guess?) so I can't load the logs. I just want to see where my spark events are like I could before? All I can seem to see at this point are the VE tables. Frustrated!

 

The Charge Dilution Effect tables help the ECM calculate fuel delivery based on "estimated" reversion taking place in the intake charge in the lower load areas, this table is in effect below 60Kpa. Reversion/EGR will vary based on the individual combination, most importantly camshaft design as overlap will affect this greatly. If you are seeying excessively high or low VE's below 60Kpa or are having trouble keeping the tune consistent in a specific area and you are absolutely your VE's are calibrated correctly, your O2 sensors are located and working properly, and the rest of your tune is setup correctly, you may want to adjust the the Charge Dilution Effect tables (CDE). Again, first and foremost get your VE tables developed. For example: if you find a trend in the VE table at 3000 RPM/40Kpa on the rear cylinder that you are reaching the high limit of 127.5, you can go into the Rear CDE table and drop the values from 2500-3500 RPM by 15% and that would bring down the VE in that area. Again, use caution and move forward in small increments with this table and be sure to retune afterwards as it will affect the mixture to a high degree. Again, before you adjust the CDE tables, make sure FIRST you have your VE tables calibrated.