01-31-2024, 07:59 AM | #1 |
Drives: 2020 Chevy Camaro ZL1 1LE Join Date: Nov 2017
Location: Earth
Posts: 108
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Knocks on Log
Hello guys just want to hear what some of you guys think of the situation. My car is recently picking up spark retard every time I go out to log now. At 1st I thought maybe it was the colder air or bad fuel but I have tried to log again in 65* weather and it still picking up knocks. Now I did notice that it only pick up spark retard when I blip the throttle as if I was about to go WOT. Example would would be that when doing a 60-130 log, it would only record knock on the hit but would not pick up anything after. Even with all this spark retard on the log, it still ran one of its fastest 60-130 time. I am thinking it might be false knock but I have not gotten on it for a few weeks now. What do you guys think I should look for or check 1st? I have tried taking timing out of the area that shows spark retard but it is all over the place and still pick up spark retard after taking out timing. I like to troubleshoot before reaching out to my tuner.
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01-31-2024, 10:50 AM | #2 |
Petro-sexual
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There's A LOT that could be.
It could be in the knock tables by cylinder. It could be burst knock. It could just be mechanical (like supercharger gearset banging around during the transition from off throttle to on throttle). It could be VTT related (TMA). Have you tried some octane booster to make sure it's not bad gas or something? If not - I'd try to run the tank pretty low. Add enough for a a handful of gallons of fuel. Add a bottle of octane booster (the verified good kind, like Racegas, VP's stuff, or Boostane), or enough such that you're getting, maybe, 100 octane, and see if you still get the retard. If you are still getting retard, I'd really look at those things listed above (and there's more) - might be false knock,or tune related. If it goes away - it's probably too much timing in that area, or something along those lines.
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01-31-2024, 11:24 AM | #3 |
Drives: 2020 Chevy Camaro ZL1 1LE Join Date: Nov 2017
Location: Earth
Posts: 108
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Thanks Radz for the insight. I will be testing the 100 octane soon here to verify it is not fuel related. Then I will probably look at the few things you suggested.
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01-31-2024, 11:50 AM | #4 |
Snackbar Tuning
Drives: 2023 SGM ZL1 Join Date: Oct 2016
Location: Florida
Posts: 1,156
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Is the car stock?
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01-31-2024, 02:02 PM | #5 |
Drives: 2017 Arctic Blue Metallic A8 SS Join Date: Mar 2017
Location: Mission Viejo SoCal
Posts: 78
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Are you doing your 60-130 with traction control on? If so, with 650+ hp, traction control will pull timing to limit tire spin. just a thought.
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02-01-2024, 08:09 AM | #6 |
Drives: 2020 Chevy Camaro ZL1 1LE Join Date: Nov 2017
Location: Earth
Posts: 108
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Car is not stock and it has been tune for the set up. It also pick up some knocks during normal cruise too.
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02-01-2024, 08:43 AM | #7 |
Drives: 2016 1SS NFG A8 Join Date: Aug 2017
Location: 46804
Posts: 6,826
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If the engine didn't exhibit this behavior prior and just started doing this, I doubt it's the tune. Tunes don't magically change, but the mechanics of the engine can. So I would start with higher octane fuel and see what happens. Next step would be to look deeper into mechanical issues with the engine.
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2016 NFG 1SS A8
Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA |
02-01-2024, 10:44 AM | #8 |
Drives: 2020 Chevy Camaro ZL1 1LE Join Date: Nov 2017
Location: Earth
Posts: 108
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Thanks! Once I test the with higher octane, if it still shows knocks, I assume that would mean it is probably a engine mechanical issue?
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02-01-2024, 04:43 PM | #9 |
Drives: 2020 Chevy Camaro ZL1 1LE Join Date: Nov 2017
Location: Earth
Posts: 108
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Can a bad exhaust leak cause knock to show up on the log? After a cold start, and once I put the car to drive and give it some gas, around 1k-2k rpm it does have some rattling noise under the car. It goes away after you drive for a bit or the rpm is over 2k. Now the log doesn't pick up knocks during the rattling. However I was just curious if a bad enough exhaust leak or rattling noise can cause knocks under heavy throttle.
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02-02-2024, 07:00 AM | #10 |
Petro-sexual
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Did you add headers? Sometime they can be noisy to the ECM. Could the rattling be there and you don't hear it, when you get under load?
I forget what your mods' were. Didn't you add a 2650?
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'20 ZL1 Black "Fury" A10, PDR, Exposed CF Extractor Magnuson Magnum DI TVS2650R // RFBG // Soler 103 // TooHighPSI Port Injection // THPSI Billet Lid // FF // Katech Drop-In // PLM Heat Exchanger // ZLE Cradle bushings // BMR Chassis-Suspension Stuff // aFe Bars // Diode Dynamics LEDs // ACS Composites Guards // CF Dash // Aeroforce // tint // other stuffs |
02-02-2024, 07:38 AM | #11 |
Drives: 2020 Chevy Camaro ZL1 1LE Join Date: Nov 2017
Location: Earth
Posts: 108
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Radz, you are correct I do have a 2650 on it and headers. The car is basically bolt on with port injection and 2650. I plan to put the car on a lift and go over to see if I can find anything.
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02-02-2024, 10:21 AM | #12 |
Drives: 2020 Chevy Camaro ZL1 1LE Join Date: Nov 2017
Location: Earth
Posts: 108
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Just an update for the group. I did some more reading and found out that the Spark Retard table for Static per cylinder was not Zeroed out. Cylinder 1 still has some value thru out the rpm. I have zeroed that out and now there is no more knocks on my log. Could I assume it was false knock?
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02-02-2024, 11:03 AM | #13 | |
Petro-sexual
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Quote:
If you're on OEM sensitivity, and on E', without commanding crazy SPARK ADVANCE - you're probably just fine ZERO'ing that whole table out, or - at least start reducing it until you see if go away. That's, obviously, assuming you KNOW you're on good fuel (or at least high octane - 100 even). It sounds like you're on the right track though. JMO.
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'20 ZL1 Black "Fury" A10, PDR, Exposed CF Extractor Magnuson Magnum DI TVS2650R // RFBG // Soler 103 // TooHighPSI Port Injection // THPSI Billet Lid // FF // Katech Drop-In // PLM Heat Exchanger // ZLE Cradle bushings // BMR Chassis-Suspension Stuff // aFe Bars // Diode Dynamics LEDs // ACS Composites Guards // CF Dash // Aeroforce // tint // other stuffs |
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02-02-2024, 12:46 PM | #14 | |
Drives: 2016 1SS NFG A8 Join Date: Aug 2017
Location: 46804
Posts: 6,826
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Quote:
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2016 NFG 1SS A8
Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA |
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