DIY_EFI Digest V5 #14:Knock sensor on Dyno

[Carter Shore]

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
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