Jump to content
remski2

Subaru Knock 6-13Khz

Recommended Posts

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

 

Oct.07.Knock_tests.pclr knock_run_2.5K.llg

Share this post


Link to post
Share on other sites

Yep the I would expect to be a second harmonic sensor (assuming stock sensor) they changed over around 2000

 

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites
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.

 

Share this post


Link to post
Share on other sites

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

2019-10-08 23_11_43-knockblock.pdf.png

Share this post


Link to post
Share on other sites
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".

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...