I'll keep this relatively short, hopefully there's a short answer. I did a datalog the other day and my table ignition vs actual ignition was off by about 5.5 degrees at around 5k. I opened up "Ignition Dwell" in the Parameters section and saw "RPM Based Ignition Advancement" and sure enough it was adding about that much to my table. Do I want all of those to be at 0.00 so it's based just off of Table + ECT +IAT + Gear Based?

I've searched the forum and found one thread on it and it did not answer this question.







-Amp

 

Leave the dwell control as is. It does some adjustments for the coil collapse delay.

Just tune the tables to MBT!

 

So it's fine that my engine is actually running more timing than I'm setting it for? I don't understand why I would want that. Would changing the table highlighted in red negatively affect the dwell and stop the pcm from automatically advancing based on RPM. That's what I'm concerned about.

I'll leave it alone if that's what I need to do, I just want to know why?

-Amp

 

The rpm based ignition adjustments are there on a factory ecu too. Neptune just allows you to log actual timing unlike Hondata. If you zero this table or disable ignition adjustments then it should be added back into your table timing for the car to run properly. I personally just leave ignition adjustments along and only make changes to the table timing.

 

This is exactly why comparing ignition numbers are dangerous/tricky/useless because you don't know if the numbers are table ignition or actual ignition. Some people tune with the dwell tables zeroed out. The number is irrelevant. Tune to MBT like Masterl1nk said.

 

At the risk of hijacking this thread, I ask a related question:

Does Honda dyno tune each and every engine that comes off the assembly line at the factory to get MBT or something similar?

Since everyone keeps saying that no two engines are alike no matter how identical they may seem, and cannot ever ever have the same timing maps, this question has been simmering in the back of my mind for a while.

Sorry I couldn't find a better place to inject this question and didn't want to start a whole new thread since it is probably a simple answer. And it kinda follows topic.

 

No, they don't. Two factory mass produced engines will be practically identical. Two hand/garage built engines will likely not.