I've been chasing a spark knock issue off and on for about 6 mos now. It seems that no matter where I put the spark tables, I'm getting a retard reading, usually when the engine is lugged.
I wanted to get some opinions at this point as I'm feeling I may be overlooking something simple. Maybe I just need to move my downshift earlier to prevent some of the lugging (with larger cam)? Maybe I really do have spark knock and need to run extra low timing? Or maybe I'm overlooking another area in my tune that could be a contributor?
Changes Made: I've posted 2 different tunes with snapshots. One tune includes a table that I had customized over time and continually pulled timing from the sore spots (which seemed to make no difference). The second includes a stock LQ4 table that I pulled from repositories. I've installed 2 new OEM knock sensors and cable, balancer, have tried it in SD mode with 02's disabled, New motor mounts, nothing making contact underneath (such as exhaust).
Engine Config: LQ4 basically stock with a cam upgrade (216/224 @ .050, .551/.551, 114), 54lb injectors, shorty headers, duel exhaust with mufflers and resonators w/o cats, cold air box, stock truck intake, stock drive by wire throttle body, 4L60E, 3:42 rear.
Background: This is an 05 Avalanche that came with a 5.3 that was swapped with a 6.0 (ATK HP93) crate engine. I've been running it for around 3 years now and have never been overly impressed with the performance (advertised at 460hp). I would like to try a fast intake and larger TB, but I want to get these kinks worked out before I make any further changes.
In my research I've seen suggestions of adding octane booster to a low tank. I plan to try that, but I figure pulling the timing back should also rule out spark knock. I'm running 93 octane.
Thanks for any thoughts/suggestions.