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Discussion Starter · #1 ·
Good day,
first of all I am sorry if I create something wrong here in the forum.

I come from Germany and no one can help me.
I have a Focus St mk3.
Now I noticed on my Cobb Ap that I keep getting negative corrections on cyl 3 and cyl 4.
They usually occur only in the partial load range.
At full load / WOT this occurs almost never.
The whole thing happens both with a Stratified Flash Tune and with Cobb Stage0 (stock software).
The corrections occur the same whether 95/98/102 octane.
Sometimes even when stationary when playing with the throttle.

I attach a few log's where I could record something and hope that someone can help me.

with kind regards from germany

Translated with www.DeepL.com/Translator (free version)


 

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Looks like your negative corrections are normal to me. They aren't limited to a single cylinder, the corrections drop and then recover quickly, and very little knocking is detected.

You need to do a proper log to know for sure.

This Stratified article tells you which parameters to use and how to do a proper log:

 

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Discussion Starter · #4 ·
Judging by the circumstances this knock occurs under, and the fact that fuel octane doesn't change it, i would say this is false knock.

Can you share your list of modifications?
is installed :
HJS downpipe 200cpi
Streetbeast exhaust system
k&n 57s
wagner intercooler

The whole thing is also not so easy to reproduce sometimes it is there sometimes not.
However, one notices when driving no change or slump in performance.

It only makes me wonder that it knocks at full load actually not at all.

Cyl3 and Cyl4 also sometimes show the same knocking, can such a sensor also be defective?

I do not know now whether I should be worried or not since I would not have seen it anyway without the AP.

attach here times still a knock from the 4th cylinder.


 

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Discussion Starter · #5 ·
have now read something in the american space and öffters times geles that this can also generate an exhaust system or downpipe.

since the knock with 102 octane also does not reduce this can be possible that it comes from the exhaust system?
the downpipe also has a very stiff flex pipe.
 

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2018 Ford Focus ST1 with a 2867 gen 2
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It's possible you're getting false knock from the downpipe/exhaust, yes. Put the car on ramps/jackstands and see if the exhaust is VERY close to touching the underside of the car anywhere. If so, adjust it (if possible) to gain some clearance.

Also check the intake hold down bolt on the top of the motor/vavle cover area as mine sometimes gets loose and causes some false knock.
 

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2014 ST3. Garrett GTX2860R Gen 2. FBO
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To add to what Rob said, pay close attention to the two downpipe hangers where they pass through the mount. Make sure these two hangers aren't protruding too far and coming close to the subframe.

Honestly, if you can't see anything obvious, I wouldn't worry about it. This isn't happening in an area that will cause you to lose horsepower or do any damage.
 
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