[JohnAh]

Thank´s for your input, Superturnier! Don´t remember how detailed I was in the first description of my FEC but l/h (fuel per time), average speed, three different average L100, different trip data and more are on my list. But TOO MUCH data can also be bad... What I realy need is a clever system for how to easily reach the information I need most while driving.

Superturnier, do you mean that you rarely read your L100 while driving, simply because it´s averaging is too short in time? I plan to have four different ways of displaying/calculating the L100: 30 seconds, three minutes, 30 minutes and trip average. I guess 3 min. is the one I will prefer to have at one part on the display most of the time while the other four digits show something else. If 3min. is the best delay/filtering of data I don´t know. I also guess that shorter than 30 sec. will give nonsense readings, just like Superturnier wrote.

I plan to have more than one "page" of data logging, each containing 5-9 different meassurements/calculations. Each page can be cleared separately. I can then use one such "page" from one tank filling to next, another page for all driving during a day and a third page that I reset several times during a trip to see how different strategies or inclination of the road will affect the consumption.

Each such "page" of data will contain average L100, total litres of fuel, total time, total distance, average speed, % of fuel wasted on idling and % of distance traveled without help from the engine.

Meassurements of time and distance will have a floating resolution. -Time will start as seconds and tenths of seconds, then change to MM:SS and then to HH:MM as there is no need to keep track of seconds if I have been driving for an hour. Same about distance and even fuel. It´s better to get rid of trailing figures that are worth nothing. Any precision should be meassured in %, not in absolute figures! However, when calculating and comparing averages or repeated meassurements it´s offcourse wise to not get rid of precision too early in the process. What´s realy important to remember is that precision can not be created within a process, it can only be a product of the input.

I try to think a lot about how much precision that is realy needed. Most absolute readings don´t need more than two significant figures. I also find it silly to have more than three significant figures in any comparative data even if the data is collected during long time or distance or is an average of multiple tests. Trailing zeros are just about appearance and readability just like the decimal point.