RomRaider

This is from an 08 STI (AZ1G202I)
Looks like below ~4500 the IAT Comp B table is in effect. The Intake Air Temp is ~55F giving ~1.8* of additional timing but the "activation" table would lower that by 50%, to ~0.9* (round down or up?) so I am not sure why the timing above 5k is lower than the sum of the timing tables. If the other "Additive" tables were in play, the actual timing would be higher than what I am calculating from Base (B/D) and Advance (2)

Why not log the actual base timing ("ignition base timing")? Learned ignition timing only takes into consideration final dynamic advance + FLKC, so you'll also need to log FBKC. I would log FBKC, FLKC, dynamic advance ("ignition timing advance"), ignition base timing, IAT, etc. If there's still some discrepancy, then I'll take a look and see if there's something else in play.

I've set that compensation table up just like the 08 WRX and 06-07 WRX. I zero'd the B map and my timing lines up perfectly with what I'm asking of it.

Guess I missed the definition of Learned Ignition . I'll have to get log the other parameters the next time I meet the owner of the STi. However, in a part throttle log from the same day, the difference is similar. It could be related to FBKC I suppose but seems like more than a coincidence.

Given the Winter weather that just got here, further logging will have to wait a bit longer.

I went through the rest of the logs and they all have the same offset above ~4500rpm. It is almost like the IAT compensation is not applied. The affected area in the Base Timing map is the same for A/B/C/D and the Learned Ignition Advance followed the Advance 2 map so the only thing left is some sort of compensation (or lack thereof). There isn't any altitude compensation for timing, is there?

Well, IAT B comp is not applied all the time - I outlined the conditions in another thread for, I think, the 06 WRX. Haven't checked if it is the same for the 08 STi or not.

You have to log the actual base timing as just because the 4 maps are the same, doesn't mean that the ECU isn't using some alternate base timing calcuation (The 08 STi has some base timing alternate logic but because it was different that prior years and I didn't have time to look at it, I left it out).

I do not see any 2d or 3d timing comp map v. RPM that would account for your discrepancy, but, of course, that doesn't mean it is not accomplished in some other way.

Probably the easiest way would be to send you some custom defs to log all the various timing compensations (known and unknown). When you have access to the car again, let me know.

OK, I'll let you know when I have access to the car again. The IAT comp that I was referring to above was the "IAT Comp A" map. I know the IAT Comp B usually stops around 4k. If I shift the entire timing curve down ~2* (the max amount calc'd from the IAT Comp A table), then the "offset" below ~4500 could be accounted for with the IAT Comp B table and everything else would line up.

Thanks

OK, finally got a chance to log this same car again. This time I logged the Base and Advance values as well as the others. Based on the temperature compensation table and the activation table, the numbers are not adding up. If I ignore the IAT comp then they line up (aside from the IAT comp B table). Attaching the log files.

ROM ID:AZ1G202I

how are you calculating the IAT a comp with the activation table? For example, if the IAT A was 2 degrees and activation was -50% then the final IAT a comp would be 1 degree, 0% = 2 degrees, -100% = 0 degrees regardless.

Yes, that is how I am calculating the compensation. The activation table is not in my spreadsheet, for now I just multiply the IAT comp A table by 50% for the logs that go above 1.6g/rev.

Well, I can send you some logger defs to log the various unknown timing compensations to see what might be coming into play. It's easier to narrow it down this way.

That would be great.

Bump. Any word on this? Airboy, what did you find was the best way to get the timing curves to line up?

I haven't had access to the 08STi so I didn't bug merchgod for the custom logging definitions. If you have access to an 08STi I would like to look at more data logs.

You could try setting the IAT Comp B table to 0 and see if things line up after that.

Anyone with 08 STi that exhibits this behavior I can send some custom logger defs and it should be easy to determine from there.