Been considering building one of the homemade knock sensors, was wondering if anyone had some tips and tricks to share? Going to keep this to a small budget of around $30-40. I like a cheap radio slack micro phone device modified to use a battery post clamp, this way I can move it around to listen to various parts of the engine, or frame/chassis. Reason why is the GN is picking up a lot of false knock, no amount of tuning will mitigate the issue. I.E. no boost, low boost, low timing, etc. Still gets knock at the same rpm every time, Im thinking it may be the noisy lifters or the down pipe touching the frame when the engine torques up in the engine bay. If I can build one and route the signal to my laptop, I can probably use the EQ to filter out some of the noise too?

Looking around for ideas...

http://www.realhomemadeturbo.com/for...?topic=22257.0

http://www.autospeed.com/cms/article.html?&A=0353