I upgraded this year from DUI HEI to Daytona Sensors CD ignition on my NA sbc. mainly for the idle stabilization features. I'm trying to better understand the "retard compensation" effect in the timing curve parameters. I have my distributor indexed at 34.0 degrees. retard comp. is set at the default 1.5 degrees. I am running a 3D timing curve with a 1 bar MAP sensor again mainly using MAP input to trigger idle stabilization built into my timing curve. When I pull a log file after running the boat, it shows max advance achieved of 32.5 degrees despite my curve calling for 34.0 pretty much across the entire MAP range above 3500 rpm. My understanding is the retard comp adds to the advance to account for the inherent higher rpm electronic lag, and this seems to be pulling timing from the system? I'm going to try to run on a hose this week and take advance readings with a light at 1000 rpm increments to get a better understanding of what the engine is actually seeing for advance. Any experience to be shared with this is welcome.

If your actual timing is at 34 degrees the box will take it to 34 degrees. It won’t exceed the actual timing. You may need to advance your distributor to 34 degrees or at least confirm that’s where your timing is locked. Maybe advance it a little beyond 34 and see what happens.