jsbsti Posted June 2, 2023 Report Share Posted June 2, 2023 Hello, on my Subaru EJ 207 the knock frequency is around 7.5kHz, how should I set the channel frequency to 7khz or 8kHz? Quote Link to comment Share on other sites More sharing options...
koracing Posted June 2, 2023 Report Share Posted June 2, 2023 You can also try 15kHz which would be second order resonant frequency and run a higher gain. Quote Link to comment Share on other sites More sharing options...
Adamw Posted June 2, 2023 Report Share Posted June 2, 2023 I would use 8K for a EJ207. Attached is a spectrograph from our EJ205. Frequency is the Y axis, you can see at 7, 7.5 or 15K there is not a clear difference between knocking and not knocking, at 8-9K it is much easier to see. 8K works good in our car. koracing, jsbsti and DenisAlmos 3 Quote Link to comment Share on other sites More sharing options...
jsbsti Posted June 3, 2023 Author Report Share Posted June 3, 2023 Here is my spectrograph @Adamw Quote Link to comment Share on other sites More sharing options...
Adamw Posted June 3, 2023 Report Share Posted June 3, 2023 8k narrow should work nicely with that. jsbsti 1 Quote Link to comment Share on other sites More sharing options...
jsbsti Posted June 4, 2023 Author Report Share Posted June 4, 2023 if I understood correctly if I set to 8k it will only take the frequencies around 8K ie from 7.5k to 8.5k? @Adamw atlex 1 Quote Link to comment Share on other sites More sharing options...
Adamw Posted June 4, 2023 Report Share Posted June 4, 2023 correct, a band pass filter centred at 8K. jsbsti 1 Quote Link to comment Share on other sites More sharing options...
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