Stock C7 | Knock Retard Logged

[zeknoxville]

Hi All-

Longtime lurker here to the forums. I own a 2016 C7 z51 A8 and recently procured a license to HP tuners. As of now the car is 100% stock and have not made any modifications to the tune.

Took the car out to log it while it is completely stock to help serve as an initial baseline before installing headers and modifying the tune.

What I noticed seemed surprising to me (but perhaps it's normal). I was able to log a pretty significant amount of knock retard at both part throttle and WOT. The WOT pull was able to log almost 7* of knock during the pull. You can notice the WOT knock within the 1:41:51 portion of the log.

Looking for any insight if this is normal behavior for the platform, or if there are specific things I should be looking into further?

I've attached the HP tuners log here for your reference. If I'm missing any channels that I should be logging, please let me know.

[Higgs Boson]

might not be knock, but rather torque management.

[zeknoxville]

might not be knock, but rather torque management.

Higgs, understood. What would be the next actionable steps to further diagnose to determine if this is real knock or torque management kicking in?

[Higgs Boson]

Higgs, understood. What would be the next actionable steps to further diagnose to determine if this is real knock or torque management kicking in?

put as much unleaded race gas (MS103 or something) as you can afford in the tank and go again, if the retard values are still there then it's not detonation.

[zeknoxville]

put as much unleaded race gas (MS103 or something) as you can afford in the tank and go again, if the retard values are still there then it's not detonation.

Understood. I currently don't have any MS103 but I should note that the log attached in the original post was from BP 93. Stock tune only requires premium gas of 91 octane.

The log does not appear to be pulling any timing from the knock that it is logging. I gotta imagine this is torq management consider its a 100% stock car and tune.

[10_SS]

Looks like real knock to me. I also see some pretty big spark dips at WOT that are probably due to Tq management @ 6:55:622 (not due to knock although knock retard is pulling timing through the entire event).

Do you have Knock Learn pid? I didn't see it in there, gives you an idea how much power/timing your losing due to learned knock retard. 0.00 = no timing reduction, 100% of timing is from the High Octane table. 1.00 = 100% timing being taken from the Low Octane table. Also see if you can log individual cylinder knock YES/NO, you can with the LS3 anyway. So when you see knock retard you should see it show up on channels as one or more cylinders as YES.

I actually think the Knock Learn value is a very powerful easy to use indication of how well your engine is running, at least what is "normal", compared to it increasing far from normal.. something is likely up (bad gas, etc). It stays after your done with WOT and other spirited driving so you can actually have a clue of what is happening the entire time. I have a little home built dash gauge showing real time IAT, Knock Learn, and a couple other values.

[Higgs Boson]

Understood. I currently don't have any MS103 but I should note that the log attached in the original post was from BP 93. Stock tune only requires premium gas of 91 octane.

The log does not appear to be pulling any timing from the knock that it is logging. I gotta imagine this is torq management consider its a 100% stock car and tune.

it will pull spark from real knock even on 93. manufacturers do not use pump gas to calibrate, they use a control fuel and find MBT, which 93 cannot support.