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Old 10-08-2019, 05:46 PM   #1
kgharrin
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Default 2019 STI Knock at WOT Need Help

I could use some help.

2019 STI
COBB DP, Catback
IAG AOS
COBB EBCS
COBB Fuel Pressure Sensor
BCP Stumble Mod
BCP Protune

I was seeing some knock at WOT a couple weeks after a protune. I took the car to my tuner and we verified compression (looked great 145-150) and put in new NGK plugs. This seemed to solve the issue until today (a few weeks after the new plugs) I am seeing the exact same behavior at WOT. What would the next logical thing to check be?

Thanks in advance.

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Old 10-08-2019, 06:45 PM   #2
rtv900
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check that your tune isn't too aggressive
if it is, which is most likely the case, ease up

how much torque did you increase from stock?
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Old 10-08-2019, 06:52 PM   #3
kgharrin
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Default 2019 STI Knock at WOT Need Help

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Originally Posted by rtv900 View Post
check that your tune isn't too aggressive
if it is, which is most likely the case, ease up

how much torque did you increase from stock?


I thought the same thing but my tuner is very confident that this is a conservative tune for 93. I am only making 315 lbft at the wheels.
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Old 10-08-2019, 06:53 PM   #4
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What did the plugs show?

What was the reasoning behind replacing them? To go with a colder plug?

What quality fuel are you using?
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Old 10-08-2019, 06:55 PM   #5
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Quote:
Originally Posted by WRXnick16 View Post
What did the plugs show?



What was the reasoning behind replacing them? To go with a colder plug?



What quality fuel are you using?


Plugs showed no abnormalities. BCP recommended these plugs for stage 2 and beyond and we wanted to rule them out as a cause of the WOT knock. My intent was to put in fresh plugs anyway and the compression test was a convenient time to do so. I run shell 93.
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Old 10-08-2019, 07:29 PM   #6
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The feedback knock of -1.4 is fairly normal at the beginning of a run at throttle tip in with big throttle changes (20-100%).

The fine knock learning of -2.1 also starts at the beginning of the run from ~4k rpm and drops to 0 by ~5.2k rpm and stays there.

Your DAM stays at 1.

I wouldn't be too concerned, but I'm not a tuner. Maybe try doing a longer pull in a higher gear while more easily rolling into the throttle to prevent any false knock.

https://cobbtuning.atlassian.net/wik...ock+Monitoring
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Old 10-08-2019, 07:55 PM   #7
kgharrin
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Default 2019 STI Knock at WOT Need Help

Quote:
Originally Posted by WRXnick16 View Post
The feedback knock of -1.4 is fairly normal at the beginning of a run at throttle tip in with big throttle changes (20-100%).



The fine knock learning of -2.1 also starts at the beginning of the run from ~4k rpm and drops to 0 by ~5.2k rpm and stays there.



Your DAM stays at 1.



I wouldn't be too concerned, but I'm not a tuner. Maybe try doing a longer pull in a higher gear while more easily rolling into the throttle to prevent any false knock.



https://cobbtuning.atlassian.net/wik...ock+Monitoring


Yeah, I have never seen DAM < 1 which is somewhat comforting. The strange thing is that I am able to learn away the FKL after a few pulls. The new ECU's use both feedback and fine learn to make on-the-fly timing corrections, so it is difficult to say whether or not it registered a perceived knock or if it was a preemptive compensation. I just don't know why it would register any knock in the first place with a good tune. Also, I can go weeks without any WOT knock and then all of a sudden (today) I see a bunch of it. Makes me think false knock / noise. I mean I have seen fine knock learn spike up to -4 deg while cruising at 70 mph downhill...it took a few seconds to unlearn it, but it was obviously a false reading.

Last edited by kgharrin; 10-08-2019 at 10:57 PM.
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Old 10-09-2019, 11:40 AM   #8
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If I pull 2 degrees across the board to see if it helps should I expect to see a reduction in knock and if not, it points towards a false reading? Anyone else have any ideas for next steps?
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Old 10-09-2019, 12:56 PM   #9
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You may get a quicker response from the tuning gurus if you post the log here:

https://forums.nasioc.com/forums/sho...760402&page=70
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Old 10-10-2019, 09:52 AM   #10
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Quote:
Originally Posted by WRXnick16 View Post
The feedback knock of -1.4 is fairly normal at the beginning of a run at throttle tip in with big throttle changes (20-100%).

The fine knock learning of -2.1 also starts at the beginning of the run from ~4k rpm and drops to 0 by ~5.2k rpm and stays there.

Your DAM stays at 1.

I wouldn't be too concerned, but I'm not a tuner. Maybe try doing a longer pull in a higher gear while more easily rolling into the throttle to prevent any false knock.

https://cobbtuning.atlassian.net/wik...ock+Monitoring
This ^^^

Did you read the article? Do you not trust your tuner that you paid $$$ to? You're asking random people on the internet, to see if this is concerning. Ask your tuner man.

I really wouldn't worry about it. Dam is at 1, FKL and FK numbers are pretty on par with about 95% of builds out there. Does your car feel like a loss in power? Any stutter? Tip in knock is pretty normal. I would be more concerned if you're getting WOT knock over -1.8 in higher RPM's.
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Old 10-10-2019, 10:10 AM   #11
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Quote:
Originally Posted by vlad11591 View Post
This ^^^



Did you read the article? Do you not trust your tuner that you paid $$$ to? You're asking random people on the internet, to see if this is concerning. Ask your tuner man.



I really wouldn't worry about it. Dam is at 1, FKL and FK numbers are pretty on par with about 95% of builds out there. Does your car feel like a loss in power? Any stutter? Tip in knock is pretty normal. I would be more concerned if you're getting WOT knock over -1.8 in higher RPM's.


I did, yes and I trust my tuner but my tuner is unsure of the issue and agrees that it is abnormal. So I am reaching out for additional input. Thanks for yours.

I see WOT knock anywhere from -2.85 ó -1.4 near redline so I think my concerns are valid. Especially since I never saw a lick of knock at WOT in the last few weeks after the tune and fresh plugs. This wasnít a one time thing, I see it consistently.
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Old 10-10-2019, 02:37 PM   #12
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Quote:
Originally Posted by kgharrin View Post
I did, yes and I trust my tuner but my tuner is unsure of the issue and agrees that it is abnormal. So I am reaching out for additional input. Thanks for yours.

I see WOT knock anywhere from -2.85 ó -1.4 near redline so I think my concerns are valid. Especially since I never saw a lick of knock at WOT in the last few weeks after the tune and fresh plugs. This wasnít a one time thing, I see it consistently.
Try putting the format of logs in datazap, log multiple ones, (from 3rd gear and 4th) and post in that thread.

How are your AFR's in WOT?
https://forums.nasioc.com/forums/sho...hlight=fa+logs

This thread gives you a good idea of at least what parameters you should be logging, for an accurate diagnosis. It is for the FA20, but still works.
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Old 10-10-2019, 03:30 PM   #13
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Quote:
Originally Posted by kgharrin View Post
I mean I have seen fine knock learn spike up to -4 deg while cruising at 70 mph downhill...
^this right here

These sensors are ultra sensitive, and the ECU knows it which is why your DAM doesn't actually change.
No tune in the world will never have those feedback knock numbers sometimes.

The fact that you got it cruising downhill proves without a doubt that you aren't actually getting real detonation.
When I first got an AP I left it plugged in and looked at all those numbers. Then I started seeing stupid feedback knock and learn under the most ridiculous conditions, like casually cruising out of my parking lot with a cold engine at 11% throttle under vacuum.
Then I realized monitoring those things with a normal tune is pointless and you just get inundated with all kinds of useless data that you obsess over.

unplug the thing
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Old 10-10-2019, 03:34 PM   #14
kgharrin
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Quote:
Originally Posted by rtv900 View Post
^this right here



These sensors are ultra sensitive, and the ECU knows it which is why your DAM doesn't actually change.

No tune in the world will never have those feedback knock numbers sometimes.



The fact that you got it cruising downhill proves without a doubt that you aren't actually getting real detonation.

When I first got an AP I left it plugged in and looked at all those numbers. Then I started seeing stupid feedback knock and learn under the most ridiculous conditions, like casually cruising out of my parking lot with a cold engine at 11% throttle under vacuum.

Then I realized monitoring those things with a normal tune is pointless and you just get inundated with all kinds of useless data that you obsess over.



unplug the thing


Yeah, I hope so. Itís just weird to me that overnight I can go from perfectly clean WOT pulls to pulling a couple degrees throughout the whole rpm band. Hopefully it stops as suddenly as it started.
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Old 10-10-2019, 04:14 PM   #15
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Quote:
Originally Posted by rtv900 View Post
No tune in the world will never have those feedback knock numbers
Except for when your sensors are unplugged or your detents set to 0 etc etc.


Gas changes, conditions change, temperature changes, how much crap you have in the car changes- itís fine.

Plus If its a -2.1 fkl in wot it probably learning out a knock that was seen weeks ago, you probably just donít hit those load cells every time you drive so it will take time to learn the timing back.

Aka put your AP in your glove box or learn what the numbers actually mean before you start watching them
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Old 10-10-2019, 04:24 PM   #16
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Quote:
Originally Posted by kgharrin View Post
Yeah, I hope so. Itís just weird to me that overnight I can go from perfectly clean WOT pulls to pulling a couple degrees throughout the whole rpm band. Hopefully it stops as suddenly as it started.
I guess man
I mean that's why 50 years ago a 60,000 mile car was OLD as hell. Because you set timing advance and peak on a distributor and that was it, period. Those weights or springs didn't have a clue what was going on inside the engine.

Now computer do know, and pulling a degree here and there is why now a 300,000 mile car is OLD as hell.

Knock detection is a crude science, and you have to let it do something unless you simply want to disable the entire system. I think you need to be more realistic about what is happening.
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Old 10-10-2019, 07:34 PM   #17
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Quote:
Originally Posted by simpleJ View Post
.



Aka put your AP in your glove box or learn what the numbers actually mean before you start watching them


Thanks for your input. I am well aware of what I am monitoring. My AP is going back in the glove box (where it was untill a few days ago) once I figure this out. The only reason I took it out was because I could FEEL it pull timing at wot. I looked and saw the knock correction and here we are. I understand the feedback and preemptive timing corrections well, but I appreciate you all trying to spread knowledge.

I zip tied a few electrical connectors down near the knock sensor and I have seen a possible improvement. Iíll keep my eye on it for a couple days to verify but Iím hoping this is a simple engine bay rattle.
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Old Yesterday, 07:54 PM   #18
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Unless your seeing higher numbers on the regular, there is 0 reason for concern here. After I got tuned I was seeing the same numbers you are, sometimes regularly sometimes not. I was told and read several articles that say those low numbers are normal and nothing to be concerned about. You should start to be concerned when the knock is closer to a 7 or above.
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