Originally Posted by
TriPinTaZ
You don't have to change the high octane table at all. It's best if you leave that table alone. The Minimum Base/Long tables are the minimum allowed spark after Torque Management Advance removes timing to bring the requested torque down along with closing throttle etc etc. Since DFCO and decel is now also driven by Torque Management this is the only area to address.
In your Minimum Base/Long timing tables drop the spark advance value to 5 degrees in the decel areas that you want crackles. For LT4 cars you want the do the .08 and .12 rows for the correlating RPM, you can do the .16 row too but don't mess with any RPM range below 1600 so that it doesn't affect DFCO and idle. When your in moderate to hard decel in the LT4's your typically at .12 or lower airmass. For LT1's you can lower the .16, .12, and .08 rows because they seem to mostly be in the .16 range on decel rather than .12 like the LT4's.
How this works in a nutshell: Say you're in second gear and you speed up with your RPM's to 4500. Then you stay in 2nd gear and let off the gas. The Airmass drops to less than .16(LT1)/.12(LT4) and the ECU starts pulling timing via Torque Management Advance. A positive value of TMA is actually the amount of timing being pulled out of the High Octane base table(plus adders). Anyhow, the Minimum Base/Long tables tell the ECU what the lowest timing value can be after Torque Management Advance pull timing. If you lower these values, TMA can pull timing down as low as you have that table set and it will do just that on moderate to hard decel. So once you set those areas to 5 degrees, test it out and see if its too much crackle. You can add timing in the areas that have too much crackle. In fact 5 degrees might be a bit too low at higher RPMs like 4000+. It might get extremely loud at that value. When I built my crackle tune I had it set to 5 degrees from 1600-2800, then ramped up to 12 degrees by 5000 RPM. This made the car crackle really nicely on command. You just have to play with the values to get it to your liking.
Note: DO NOT interpolate or smooth between the .16 and higher rows. Leave them stock. You ONLY want to change the values in the cells where you are on moderate to hard decel. If you change them in cruise or light decel airmass rows, you will get significant cruise oscillation in throttle and if you're a manual it can really mess with you on gear changes and cause stalling. My advice here is to datalog the car with its current tune and replicate the scenarios where you want the crackles. Then go into your tune and only modify those areas in the Minimum Spark tables. No other changes are needed to any other tables to make the crackles.