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-   -   NB OEM Knock Sensor Output (https://www.miataturbo.net/general-miata-chat-9/nb-oem-knock-sensor-output-33610/)

sv650_ck 04-05-2009 03:12 PM

NB OEM Knock Sensor Output
 
1 Attachment(s)
I'm not hearing any knock but the knock sensor hit 104 (units?) on a boosted run. How does the sensor output correlate to damaging knock? Should the timing be retarded above a certain level?

Stein 04-05-2009 03:37 PM

I've seen some 100+ readings as well and have never heard any knock. Not sure what to make of it.

I tried to load a couple of my runs into Megalog Viewer and have been unsuccessful. What format do they have to be saved in? .csv?

sv650_ck 04-05-2009 03:58 PM

It should be in the .csv format but you have to remove the quotation marks from the header - See Turbo Roaches post below. I opened the file up with note pad and cut and paste TR's header and resaved.

https://www.miataturbo.net/forum/t33439/

JasonC SBB 04-05-2009 04:16 PM

The NB factory sensor output needs to be filtered to help the signal to noise ratio. I posted a schematic for such a filter in the ECu section.

ZX-Tex 04-05-2009 10:09 PM

Here is a good thread on the Adaptronic forum:
Knock Logging...
Based on this thread the level you are seeing is about right. The Adaptronic has a programmable filter built-in which is what the thread is about.

Based on some use of electronic det cans, you can still have some light knocking that you will not be able to hear listening normally. So be careful.

JasonC SBB 04-06-2009 02:23 AM

I glanced at that thread, and they dont seem to be talking about frequency filtering that I'm talking about.

sv650_ck 04-06-2009 07:39 AM


Originally Posted by JasonC SBB (Post 391471)
The NB factory sensor output needs to be filtered to help the signal to noise ratio. I posted a schematic for such a filter in the ECu section.

Does it give you a line level output that you'd plug into an amp of some sorts?

ZX-Tex 04-06-2009 10:54 AM

No it is more like a microphone than a line output; it is a passive device. But it has enough power though to plug it into an amp.

Jason you are right as far as i can tell the Adaptronic setup is just a gain versus RPM filter, not a frequency filter.

sv650_ck 04-08-2009 05:54 PM

1 Attachment(s)

Originally Posted by ZX-Tex (Post 391771)
Jason you are right as far as i can tell the Adaptronic setup is just a gain versus RPM filter, not a frequency filter.

I found this in the manual - appears there is filtering.

JasonC SBB 09-09-2009 10:47 AM

FWIW the circuit I designed is more specific for the miata - it has a narrow bandpass filter tuned for the miata block's knock frequency. It also provides the power necessary to power the factory knock sensor. Its output voltage will be compatible with knock inputs designed for piezo sensors.


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