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Old 02-08-2014, 03:33 PM   #1
ZXNasty
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Default getting more knock recently

I've been noticing that I'm getting quite a bit more knock lately.
I constantly monitor Feedback knock, DAM, Fine Knock Learn, and A/F ratio

I typically get some feedback during normal acceleration as I let off the gas to shift, just a normal. 1.40 value.
Lately I've been noticing it happen more often. Not sure exactly what circumstances it's happening under since I can't stare at the AP all the time. The DAM and Fine Knock learn never change and are there respective normal values. AFR looks within normal ranges, as does boost (not over or underboosting) I attemped some logging today, but during none of the logs did I see any Knock so not worth submitting.
Is this normal?
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Old 02-08-2014, 03:50 PM   #2
mikeydrives1
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2001 Forester
STi II type M

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Well, Knock at wide open throttle, esp once boost is at full force, is what is the true worry. Many times, knock sensed when just driving normally or even when shifting is percieved by the ECU as knock, even though it may be false.

Now perhaps we can help see if this is normal or not, but we will need to see some Logs of it, capturing when it happens.

Also, it would help us lots to know the details of your vehicle, what kind of parts it has, who has tuned it, or if its using an off the shelf COBB tune.
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Old 02-08-2014, 04:35 PM   #3
ZXNasty
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Default

Sorry skimped on the details. Running a Cobb AP with an off the shelf stage 1 tune. No intake or exhaust.
2014 wrx. I've tried to get logs buts it's do random I haven't been able to capture it yet. As far as I understood it could be false knock just seemed like I've seen it more lately but I suppose it could be the weather or this tank of gas. And I've never once seen knock at WOT or full boost. Occasionally once the throttle is let off which is normal
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Old 02-09-2014, 12:04 AM   #4
steezle
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2013 WRX Stage 2
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I have a 2013 WRX Hatchback with stock intake, stock DP running Stage 1 91 tune. If I leave the feedback knock on and drive around town, I usually see that there has been a 1.4 or even 2.8 knock value recorded. Never more than 50% throttle or any spirited driving, but it seems to happen every time I drive the car around town. Never notice when the knock happens, just see that it has logged it at some point.
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Old 02-09-2014, 12:21 AM   #5
Clark Turner
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A lot of people are hyper sensitive to feedback or fine knock learning values. This simply means the system is doing its job. If the car runs with 0's most of the time and sometimes it has negative values, this is fine. The system is working. If it all the time everyday is showing negatives or very high value negative, then the car might need some attention. Watching feedback like this is a complete waste of time. Instead, watch the DAM. if its 1.0 on newer car or 16 on an older car, you have nothing to worry about.

C
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Old 02-09-2014, 01:00 AM   #6
ZXNasty
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Default

Quote:
Originally Posted by Clark Turner View Post
A lot of people are hyper sensitive to feedback or fine knock learning values. This simply means the system is doing its job. If the car runs with 0's most of the time and sometimes it has negative values, this is fine. The system is working. If it all the time everyday is showing negatives or very high value negative, then the car might need some attention. Watching feedback like this is a complete waste of time. Instead, watch the DAM. if its 1.0 on newer car or 16 on an older car, you have nothing to worry about.

C
That's kind of what I figured. Just wanted to make sure. Appreciate all the help
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Old 02-09-2014, 07:41 AM   #7
Trini_subaru
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Default subaru crosssport 2006

hi guys I am from Trinidad I have a cross sport model forester need o be tune but the problem is ecutek alone can tune this vehicle.. I have doubts with the dude who tunes... Is there any other methods or engine management I can use besides ecutek? Cobby and opensource can they be used to tune this vehicle?
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Old 02-12-2014, 12:32 AM   #8
211STi
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Hey ZXNasty, I am in the exact same boat. I have a 2011 STi sedan with 93oct Stage 1 LWG map(because I was overboosting) and Magnaflow catback. I have since monitored the same readings constantly. While driving around town I randomly see -1.4 and -2.8 in feedback, and rarely (the same values) in fine knock learn. This has been typical ever since I got the AP, which was about a year into having the car. So I've personally attributed it to being okay, especially since I don't see these numbers with WOT pulls.

(TLDR: I don't recommend running an AEM high flow panel filter w/o a pro tune) Just a side note... I've learned a lot about how advanced Subaru's knock system is what I would consider one of the best. Sensitivity is the prime reason I attribute it to being the best, after all you want it to sense and then pull timing appropriately. I began reading about this after I installed and ran an AEM high flow panel filter with the stock airbox and the 93oct Cobb CPF+ Stage 1 OTS map. I did a few logs and monitored the car for a bit but stowed the AP away since no knock was occurring. Fast forward about 3 months, I connected the AP and noticed the DAM was .65 and I was getting -5 in feedback, -2.8 learned, and any throttle -1.4 feedback which would decrease to zero. I immediately re-flashed with a 91oct backup tune and replaced the AEM with the stock filter. All is well so far (-1.4 feedback rarely), but now I'm worried cause I might have to upgrade sooner than I would have liked.
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