DIY_EFI Digest V5 #14:Knock sensor on Dyno

[Bruce Plecan]

I didn't say they were.  That's why I said to get a few and try them...
And BS to engine specific.  The one I'm running in my F-Body (355 CID), is
from a 3.8L 85MY, as I recall.  See I went and got several ESC moddules, and
sensors and actually tinkered with mix and matching them, so I do have some
notion on how the things ACTUALLY work.
  Audio analyzer, gee great.  I did my actual on car testing with a $20 old
scanner, and will match my results to anyone's.  Theory is fine, but
execution is what matters!!..
Grumpy
  Hmm, wonder why?.

| Bruce,
| I believe that the sensors are built to be sensitive
| to specific frequencies, to minimize false trigger,
| etc. In other words, they are specific to a given
| engine.
| I have been working with freeware audio spectrum
| analyzer program that uses the sound card on a PC. By
| connecting a wide band microphone to the motor, and
| then simulating knock (resembles pounding on the block
| with a hammer or broomstick), the characteristic
| frequencies of a given motor can be determined. The
| resonant frequencies show up as spikes. If you can
| safely induce actual knock in the running motor, even
| better results.
| Using that info, the PC software can be set up to look
| for knock signals for that specific motor.
| All freeware, just need to bolt on a microphone
| (guitar mic?) Save the results on a floppy.
| YMMV, I'm just playing with it right now.
| Carter Shore