Understanding Knock NB2
02-25-2020, 10:06 AM
#1
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Join Date: Jan 2017
Location: "lol", MA
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Understanding Knock NB2
I'm running an MS3Pro in my 05. I'm trying to understand what is knock, and what isn't. The engine is N/A with I/H/E. VICS manifold has also been swapped on.
At idle I'm seeing 5-7% knock. It scales fairly linearly with RPM, but occasionally I see spikes. I understand that there is noise in the signal, so that is where I'm seeing that 5-7% at idle and the linear scaling as RPM goes up.
I'm interpreting spikes as potential knock. Are there any good resources for understanding the MS3Pro's knock signals for a Miata?
My ECU is using DIY's stock values, which I've read to be good. However I've also read that every engine is different and will require changes in the knock settings based off of mods.
I'm also running poly diff bushings, MSM motor mounts and VMaxx Sports.
Log
https://drive.google.com/open?id=1Yo...xzU7oxsG6JbXLA
Tune
https://drive.google.com/open?id=1Gg...aL31S0vlk7fpA-
At idle I'm seeing 5-7% knock. It scales fairly linearly with RPM, but occasionally I see spikes. I understand that there is noise in the signal, so that is where I'm seeing that 5-7% at idle and the linear scaling as RPM goes up.
I'm interpreting spikes as potential knock. Are there any good resources for understanding the MS3Pro's knock signals for a Miata?
My ECU is using DIY's stock values, which I've read to be good. However I've also read that every engine is different and will require changes in the knock settings based off of mods.
I'm also running poly diff bushings, MSM motor mounts and VMaxx Sports.
Log
https://drive.google.com/open?id=1Yo...xzU7oxsG6JbXLA
Tune
https://drive.google.com/open?id=1Gg...aL31S0vlk7fpA-
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02-25-2020, 10:43 AM
#2
Tweaking Enginerd
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Join Date: Mar 2013
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Many people only view the forum via mobile. Posting a screen-shot of a scatter plot (RPM on x, Knock-in on Y) may get more feedback. A screen shot of the time domain plot for the specific signal artifact you are speaking about may also be helpful.
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02-25-2020, 11:06 AM
#3
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Join Date: May 2017
Location: Louisville, Co
Posts: 466
Total Cats: 86
Ted! How's the car?
Anyway - Byte it sounds like it is time to make your own knock headphones. There is only one way to truly believe the electronic knock sensor results. Your settings of gain, filtering, knock sensor behavior, mechanical noise, electrical noise, road noise. It all makes it impossible to know the real answer.
I don't trust electrical knock headphones. I've got the heavy duty safety ear muffs with holes drilled in (both sides) to feed nylon piping into my noggin. I like to attach the nylon tube to my block as close to the cylinder as possible. Then here is the part people don't like, induce knock. 70kpa, 3000 rpm you can induce it fairly easily. Listen carefully, and when you hear it, a light bulb will go off in your head and in your MS log.
It is an invaluable exercise.
Anyway - Byte it sounds like it is time to make your own knock headphones. There is only one way to truly believe the electronic knock sensor results. Your settings of gain, filtering, knock sensor behavior, mechanical noise, electrical noise, road noise. It all makes it impossible to know the real answer.
I don't trust electrical knock headphones. I've got the heavy duty safety ear muffs with holes drilled in (both sides) to feed nylon piping into my noggin. I like to attach the nylon tube to my block as close to the cylinder as possible. Then here is the part people don't like, induce knock. 70kpa, 3000 rpm you can induce it fairly easily. Listen carefully, and when you hear it, a light bulb will go off in your head and in your MS log.
It is an invaluable exercise.
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