I did a little data logging during a couple test pulls and wanted to get some insight from the team. I'll post a graph with some data after I re-take it with fewer channels captured to improve the sampling rate.
All the mundane stuff is fine (throttle position sensor reads 100%, temperatures are good, etc). Also, the mixture is fine and the O2 sensor readings indicate no hint of fuel starvation and at wide open throttle and full boost the O2 sensor is reading a little rich which I'm sure is intentional to protect the engine. The recorded boost is exactly where it should be.
However, the timing advance does indeed look pretty strange. At low load and partial throttle leading up to the pull I have about 28 degrees. When I put the hammer down the advance is retarded and drops back to 16 degrees by the time the RPM's are at 3000 and boost is building. When at 5000 RPM and full boost the timing advance is down to only 9 degrees. After a gear change and hammer down again the advance comes down to 7.5 degrees at 5500 RPM and full boost.
With such retarded timing at high RPMs it's no wonder I have no acceleration at speed.
So now for a couple questions -- what kind of timing advance should I be expecting at reasonable engine RPM's? I'd expect far more than I'm seeing, but I'm not sure what is typical since I don't have a baseline that recorded this on my car.
What are likely culprits for my ECU retarding the timing so badly? The knock sensor seems like a primary input the ECU uses to retard timing, so is it susceptible to failing in a way that makes it falsely trigger?