tuning out delay in DBW
Yes, I looked at that table and see that at .68 g/cyl and 600rpms it is using -11*, but why is it doing so? The corresponding cell on the spark table does not read -11* in either high or low octane tables. Obviously one of the modifiers is doing this. Is this where I should have been logging the modifiers and looking at their histograms?
I also notice that it drops rpms just slightly for a millisecond the instant I hit the gas which is what is making it drop to the 600rpm cell. Before that it isn't retarding nearly as bad but I assume it then smoothes up which causes the period of retard before it advances?
I also notice that it drops rpms just slightly for a millisecond the instant I hit the gas which is what is making it drop to the 600rpm cell. Before that it isn't retarding nearly as bad but I assume it then smoothes up which causes the period of retard before it advances?
Last edited by patooyee; Jun 11, 2012 at 07:06 PM.
Yes, I looked at that table and see that at .68 g/cyl and 600rpms it is using -11*, but why is it doing so? The corresponding cell on the spark table does not read -11* in either high or low octane tables. Obviously one of the modifiers is doing this. Is this where I should have been logging the modifiers and looking at their histograms?
Use your histogram and plot your total timing, and compare it to the table in the tune. You can also log burst knock retard, retard due to IAT, retard due to ECT, etc., but I never do, I just log actual timing, and knock retard and figure out the rest in my head. It ain't hard.
This is what I am looking at. At the intersecting point on the hist the high octane table says I should be at 0* and the low octane says -16*. It is at -11* according to the graph. Based on what you are saying I am interpreting that it is either burst knock, IAT spark, or ECT spark that is causing that? So ideally I would cross reference .68g/cyl on all of those logged tables (which I wasn't logging) to find out which one was causing it? Or I can just go into my tune and cross reference?
I'm just going to forewarn you, I believe the only dumb question is the one left unasked. I care not if anyone makes fun of me. My mission in life is to learn, not to be cool. Beyond my wife and kid I couldn't care less what anyone thinks about me. Thus, no question is too dumb and I am libel to amaze you with my idiocy. But your patience and willingness to help is infinitely appreciated and will always be remembered.
I'm just going to forewarn you, I believe the only dumb question is the one left unasked. I care not if anyone makes fun of me. My mission in life is to learn, not to be cool. Beyond my wife and kid I couldn't care less what anyone thinks about me. Thus, no question is too dumb and I am libel to amaze you with my idiocy. But your patience and willingness to help is infinitely appreciated and will always be remembered.
Did some reading up on burst knock. It is basically pulling timing IN ANTICIPATION OF knock to prevent it. It pulls values from the base vs. cyl delta table and subtracts them from timing. My g/cyl jumps from .24 to 1.04 when I stomp the gas. Being that that delta is greater than any value in the base vs. cyl delta table I assume it uses the max value of -12*? That would make sense why the next reading is -11*? Am I getting this right because I feel like I just had an epiphany. 
You can log all the timing retard pids to figure out which is pulling the timing and then you know where to start working. Most of the time it is burst knock that is why I said to zero it out and see what happens. If you zero out the base vs cylair then it will pull 0 deg. Then if you get knock retard you will have to lower those cells in the timing table. Or give the burst knock the ability to pull some timing.
You may have success removing burst retard completely but you might want to log it periodically for knock. GM put that there for a reason so if you start seeing knock when you stomp the throttle then you should slowly scale it back in. Safe route would be to take 50% off and leave it active. Final numbers depend on weather, IAT, ECT, A/C usage, etc. Good luck.
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