I've got a 2014 Silverado Reaper truck i'm finishing up. It's having an audible knock/pinging under low rpm/high load situations typically in 5th and 6th gear, as seen in the screenshot.
I have reduced the amount of knock retard by pulling timing, but the sound coming from the engine is still the same. I tried adding a couple degrees first as I've heard that too low advance will cause knock in these DI engines, but that made no improvement, so i started removing advance. Timing is getting pretty low and as i said, this only seems to occur in 5th and 6th gear cruising down the highway. I've increased the trucks tendency to downshift and to unlock the converter, but that hasn't made a significant improvement.
I'm just wondering if anybody else has dealt with this on a similar application and can verify if i need to continue pulling timing or look elsewhere? I just feel like i've pulled enough timing it shouldn't still be making noise. Is it possible that it's really going to like 0-5 degrees in that load/rpm range? I know i need to just go out and test it, but i'm kind of searching for a warm fuzzy feeling that i'm going in the right direction from someone who has done it. I'm still getting a grasp on these gen 5 engines. I have the tuning school book and while they give a good description of how the virtual torque system works, i don't agree with their approach on all things and the results I've seen differ from what they say should happen...specifically increasing the toruqe model, peak torque, and driver demand tables....with this truck, I can't get the "max torque," "engine torque," and "peak torque" to correlate like they do in the book. I've read all the threads on this topic here and have concluded there's a table or 2 missing that we can't see as others have guessed. Anyway...
I've adjusted all the torque parameters and tuned the VE and MAF and the truck runs a LOT better than it did stock. The lingenfelter tuning was surprisingly close to a stock calibration.
Fuel is 0% ethanol 91 octane. The truck is all stock as it came from lingenfelter with the magnacharger with the exception of a ZR1 MAP sensor.
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