Thread: need some pointers on tuning ls4

I'm currently helping a local tune his 06 impala ss ls4. I have dabbed in mainly fbodies and looking at the ls4 setup theres tons of more data and tables than I anticipated. in searching on here as well as other forums (hptuners for example), a couple members mentioned "reduce the burst knock air delta table 10%". which table is that? I noticed a section call burst knock retard but I also see 3-4 fill in data followed by the one labeled something like aircyldelta and within that table has values that are whole numbers, meaning you cant enter anything with decimals.

also regarding the spark advance. I noticed that when I was logging a WOT run, it was 28* with 2 degrees of KR at 0.68g, so in theory the car's trying to command about 30-31*. in the high octane table I noticed in the cyl airmass 0.68g it was set at about 34 degrees while in the low octane at about 23 degrees. IIRC the pcm would take the averages of the 2 tables which if correct is about right in the pcm trying to command 30-31 degrees. in the LS1 world, long as premium fuel is used, ppl have copied the high octane table into the low octane table. is this advisable for the LS4 as well?

also the current stock PE enrichment is set at 1.21 or 12.15. aside from the 2* of KR which I imagine GM set the KR on the aggressive side, is it alright if I set the PE EQ to something like 1.18 or 12.5 after possibly lower the KR sensitivity a bit?

ECM table 12765 is the cylinder air delta table you adjust. When people say reduce by 10%, you don't actually try to put that value in there. Just enter .90 in the adjustment box up top and click multiply, that will then reduce the table by 10% in this case.

Or for any table if you wanted to add or remove 2% it would be either 1.02 or .98.

I disable burst knock completely, it's not required. Just zero out the whole table.

Reduce the timing a few degrees, aim for mid 20's at WOT. Verify what cylinder airmass the engine is at under those condition and lower the timing as required. Lower the low octane table the same amount.

It is never okay to copy both high/low tables when running a stock operating system. If there was knock, the computer could never pull timing and use the knock learn factor to blend the timing from the high to low. Even with 91+ octane fuel or whatever you still want the timing to be different.

The computer is always using the high octane table unless the knock learn factor is being used. You have several other spark correction tables that are adjusting timing as well, so be aware of those. There is a base fuel spark correction, intake air temp spark correction and coolant temp spark correction to name a few, other can be torque mgnt based. Logging all those tables would tell you what is adding to the base high octane spark table.

Low 12's AFR is about perfect for safety and torque. I command 12.2-12.3 on pump gas, even when I don't have a wideband hooked up. No sense in running it on the edge with 12.7 or higher to have minimal gains.

thanks for the insight on the burst knock delta table. i'll readjust accordingly when I meet up with the guy.