remski2 Posted October 7, 2019 Report Share Posted October 7, 2019 Hi. I am pretty sure that the knock on my ej257 is supposed to be set to 6Khz (narrowband). Looking at the math from the manual Knock Resonant Frequency (Khz) = 1800/(3.14 * piston diameter in mm) 1800/(3.14*102.5) = 5.59Khz I went through the knock setup exercise in this post.. While the car was stationary I was holding throttle at ~2000rpm and changing through 4-16Khz setting in the Freq Channel. (my gain is 5) There was no significant change in the knock reading between all of them. Always ranging from 30-80. What gives or what am I doing wrong. I've done pulls and I've seen higher reading when on boost though. Attaching my log and map file. Thanks Remi Quote Link to comment Share on other sites More sharing options...
Simon Posted October 7, 2019 Report Share Posted October 7, 2019 The later model EJs used a second harmonic sensor. The frequency will be up around 12kHz Quote Link to comment Share on other sites More sharing options...
remski2 Posted October 7, 2019 Author Report Share Posted October 7, 2019 4 minutes ago, Simon said: The later model EJs used a second harmonic sensor. The frequency will be up around 12kHz My is from 2005. Quote Link to comment Share on other sites More sharing options...
Simon Posted October 7, 2019 Report Share Posted October 7, 2019 Yep the I would expect to be a second harmonic sensor (assuming stock sensor) they changed over around 2000 Quote Link to comment Share on other sites More sharing options...
remski2 Posted October 7, 2019 Author Report Share Posted October 7, 2019 There was always only one. Quote Link to comment Share on other sites More sharing options...
remski2 Posted October 7, 2019 Author Report Share Posted October 7, 2019 I see what you mean by "second". I'll change the seettings to 12K then Now.. for the no change on different frequencies.. is that normal ? Quote Link to comment Share on other sites More sharing options...
Adamw Posted October 8, 2019 Report Share Posted October 8, 2019 11 hours ago, remski2 said: Now.. for the no change on different frequencies.. is that normal ? Was the engine knocking when you where testing it? Your sensor being a resonant frequency type only outputs a strong single near frequencies it was designed to detect. So if it wasnt knocking at the time you where testing it there would have been very little signal coming from the sensor. Quote Link to comment Share on other sites More sharing options...
remski2 Posted October 8, 2019 Author Report Share Posted October 8, 2019 8 hours ago, Adamw said: Was the engine knocking when you where testing it? Your sensor being a resonant frequency type only outputs a strong single near frequencies it was designed to detect. So if it wasnt knocking at the time you where testing it there would have been very little signal coming from the sensor. Thank you. Quote Link to comment Share on other sites More sharing options...
remski2 Posted October 9, 2019 Author Report Share Posted October 9, 2019 Ok.. Now I am confused. I've looked at bunch of maps and it varies between 6 and 13Khz I cant find anywhere where it says if its a second harmonic sensor or not. Looking at your knock block manual its supposed to be 6Khz.. (since my engine is USDM 2005 ej257) Which one really is it ? Thanks Remi Quote Link to comment Share on other sites More sharing options...
Adamw Posted October 9, 2019 Report Share Posted October 9, 2019 3 hours ago, remski2 said: Looking at your knock block manual its supposed to be 6Khz.. (since my engine is USDM 2005 ej257) The line you are reading says "Bosch aftermarket sensor" which is a wideband type. As Simon already said yours is a resonant type and will want to be set around 12 or 13KHz. A 2005 car fits into the category at the bottom of that table "V7 onwards factory sensor". Quote Link to comment Share on other sites More sharing options...
remski2 Posted October 9, 2019 Author Report Share Posted October 9, 2019 Thank you for clearing it up for me. Remi Quote Link to comment Share on other sites More sharing options...
Babych44 Posted October 15, 2019 Report Share Posted October 15, 2019 What about classic Imprezas? Are those all narrowband 6khz? Mine is 1998 gt if that matters Quote Link to comment Share on other sites More sharing options...
Adamw Posted October 15, 2019 Report Share Posted October 15, 2019 I would say unknown, but most likely it is a wideband sensor. 6KHz should be in the ball park Babych44 1 Quote Link to comment Share on other sites More sharing options...
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