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Message: [QUOTE="TARM, post: 311365, member: 578"] Bill, Matt, Dave, Charles, 907Dave etc anyone else that may know definitively the answer, I have been going over my old chart and redoing a chart to more accurately compute the available PW. Matt thank you for all the phone time tonight. It is so helpful to bounce ideas off someone that has such a strong grasp on the subject matter at hand. In doing this something came up that maybe just me as not doing any tuning myself has misunderstood. It has to do with the injector delay. Now as I understand it we have a minimum injector delay. This is basically the time from when the injector is told to fire until it actually start to fire and inject fuel. This has been found to be 0.7ms. Is this correct? Is this delay from the time the IDM sends the signal to energize the solenoid till the time where the injector actually starts to spray fuel out of the nozzles? Or is it only when the injector first starts the process to firing? I know things are happening fast but I recall Dave taking the time to post the series of events the injector goes thru before any fuel actually comes out of the nozzle and I just want to make sure this is part of that and if not how much time in ms are we talking about. Here is why I am asking. I have started to work on a chart to break down just how much of a PW window we have at various RPMs going from 2000-5000rpms. I felt this could also be helpful for other to see. Also have it crossed with data from the 80% IDM values to show how this compares to what the limits are of the IDM signals. Two things are giving me a little bit of hang up. [B]1:[/B] Injector delay with a static time of 0.7ms [B]2:[/B] SOI Advance BTDC and how corresponding increase with increases in RPMs [B]Starting with #1[/B] is it correct that this is a fixed static delay and 0.7ms is accurate enough assumption of this delay? Dave, Does your modification to IDM effect this delay and if so how much have you found it does? To me if its 0.5ms or more its worth noting and adding into our factors in estimating our PW window. Any info you are willing to share would be greatly appreciated on this. If anyone else has done testing on this with modded IDMs I am all ears on effects on delay or any effect is has on the injector speed vs com PW. I assume this delay is part of the IDM signal and thus gets added in to commanded PW as it's part of the PW signal of the IDM [B]On to #2 issue:[/B] I was working off a figure of 15 degrees BTDC @ 3K rpm Based of that I figured a decline in advance as RPMs drop and increase as they increased. Worked out a rate of basically 5° for every 1000rpms in either direction. So basically with 15°@ 3K I worked up from 2K@10°, 2.5K @12.5°, 3K @15°, 3.5K@17.5°, etc up to 5K@25° I want to confirm that this sort of rate is correct and is there a limit to this. I found some very interesting associations when following a rate like this and factoring in time. If anyone can help me with these and some insight on them that would be helpful. Once I have this I will feel more comfortable with the numbers I have come up with and will post up the chart for review and hopefully so good discussion. [/QUOTE]