Four Main Spark Tables vs Cam Angles LNF/Kappa

[npaz]

Has anyone worked out the relationship between the four spark tables and when the switch occurs based on the cam angle positions? The table titles represent the extreme of all available angle positions.

Intake Min, Exhaust Min
Intake Max, Exhaust Min
Intake Min, Exhaust Max
Intake Max, Exhaust Max

Intake Cam Angle:
Exhaust Cam Angle:

Is there an easy way to look at the Cam angles at any given time on a log and determine exactly which table is being used?

There would seem to be an infinite combination of less extreme intake and exhaust angles, many of which could land on more than one table.

Thanks!

[cobaltssoverbooster]

No because it's not a physical switch they are blending constantly.

[npaz]

Hey CSSOB. Thanks for that. I figured that was the way it worked, but wanted some confirmation. I see why you and others have recommended going with the same table for all four.

I saw from your video that you created a single table for all four by just picking one. I like the idea of more control, but did you run into any issue with that method? Three of the tables are pretty close, but the Intake Max, Exhaust Max table has a lot more advance in the lower rpm, lower load range. Any issues using the lower values from the other tables?

[MikeM173]

You can log intake and exhaust (demanded and actual), and you could look at that exact timeframe in the log and determine which table is being used. The thing is you don?t need to do that. So many things blend in the tune, and you can still create an ideal tune by making all of the cam tables the same and making all of the spark tables the same, along with the op spark tables. Honestly, most people don?t seem to understand the spark and op spark tables, that I wouldn?t try learning them while messing with all four tables. After you fully understand them, you could then make the decision to mess with them separate if you choose. That?s just my opinion.

[npaz]

Thanks Mike. I'm logging actual intake and exhaust and was using that to try and figure out which table was being used at any given time. Didn't know I could log commanded which would be better at determining the table.

Any insight on creating one master table for all four? As I mentioned, three tables seem close enough that just using one would be fine. However, the fourth table has quite a bit more advance in the lower rpm, lower load range.

[cobaltssoverbooster]

no you would want some pretty sophisticated equipment to lock in a multi-dimensional and multi-phase table set like that. You can do it with what we are given but it wont be beneficial without the correct tools. There is no efficiency loss when dumbing the system down to one multi-d table set.

[MikeM173]

I would change all four to match. Timing usually needs to be bumped up everywhere anyways, so I wouldn?t worry too much about it. I haven?t looked at a stock table in a long time, so don?t just start adding everywhere based on what I just said haha. Read over my timing posts, and take a look at my complete starter tune. I think I made some spark table changes in that. They probably aren?t ideal, but it may give you an idea of bumping up spark. Hopefully someone else like CSSOB and T-Man can chime in since they probably know the tables better then I do.

[cobaltssoverbooster]

i start by stabilizing the idle cell range ignition values to prevent wandering and set a known good max advance value. click blend twice call that a good start. generally speaking the spark advance tables are down roughly 2-3* in cruise but they wont usually accept more advance unless you shift the cams.
its all collective adjustment.

[T-Man]

To keep it simple, try to blend and smooth all 4 main spark tables into one table. With trial and error, you will find what works best for you. I personally didn't deviate much from the factory idle area and worked that through the DAL and OS tables to achieve my desired idle.

Once you've done that, then move on to setting up your OS tables to your own preference. Mike and Bill's collaborative write-up is a perfect place to start. Another good thread is GMTech's OS thread.

As an example, here's what my main spark table looks like. Do keep in mind, I run 35-40% ethanol. So some of my low load/cruise and mid-range timing will be a little more aggressive.

Capture.PNG

[npaz]

Thanks for the help on this! Working on a one table solution.