Knock sensor gain tuning - best practice

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dr_jones
Posts: 162
Joined: Wed Jun 08, 2016 3:24 pm

Knock sensor gain tuning - best practice

Post by dr_jones »

Playing around with knock sensor gain tuning I began to wonder what the best practice for setting up overall gain control along with individual gain tuning - heres how I've approached it on my EJ22:

- Set all cylinder individual gains to 1
- Set overall gain to get my **quietest** cylinder (cyl1) around a knock value of 3 - this gives me a gain control value of .308 (does it matter this is so low?
- taken the knock averages for cyl1-4 from the subsequent log whilst idling and calculated the necessary gain tuning on cyl2 to 4 to give a reading of 3 as per cylinder 1.
- thrown that out as whilst it was closer looking at sCal gauge traces I'm a still out...
- manually adjust cyl 2-4 gains to get as close as I can to cylinder cyl1

So final numbers are
gain control: .308
cyl1: 1.0
cyl2: 0.95
cyl3: 0.85
cyl4: 0.65
bandpass: 5.9 kHz (based on 97mm bore)

...Does this seem reasonable? I could of course have used a higher overall gain control number and used individual gain tuning on all cylinders or alternatively used the noisiest cylinder as the baseline and turned the gain on the other 3 up (rather than down) to match.#

Not sure of best practice - or even if it really matters as such - be interested in hearing any feedback on this..

-Ed.
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