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RPM/Sec ???????????

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I've been datalogging a lot the past week in order to partially finish my tune until I have time to hit the dyno and I have noticed on the calculated fields of MegalogViewer HD there is function called "RPM/Sec" and what I noticed is that there are negative values and spikes here and there! Does that mean my engine is decelerating at some points? If yes does this mean that my ignition timing is off at some point? I have attached some log files for refference

Attached Files

A negative RPM/s value when you aren't changing the throttle, could indicate a misfire, or just an increase in engine load (like driving up a hill). Is there a specific point in your data that you are concerned about? I was looking at the acceleration occurring about 46 seconds into perama.csv, I notice the time stamps aren't regular, so the RPM/s calc may be off. I think to use that effectively, you need to be sampling the RPM much more frequently (10/sec or faster).

BTW - if that is a normally aspirated engine, 22 deg of ignition timing at WOT may be conservative.

@David Ferguson first of all I want to thank you for your help throughout my posts! If you notice there are some huge spikes here and there! Also I happen to notice some backfire at low rpm! The reasons for the conservative timing are 2 1) there isn't a consistent quality of fuel and 2) I don't have any knock detection system to check! So I try to stay on the safe side! I'll try to check if I can increase the sampling rate I'm still on the factory ECU so I don't know if it is possible!

In the second log, at about 76 sec, there is a spike in RPM that is not a real spike in crankshaft speed. Most likely an issue with the crank position sensor or some sort of data packet error in the data itself.

At 260 sec, there is a huge dropout on several data channels that is a suspect grounding/wiring issue.


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