DIY Detonation detector
and amplified engine ears ( part II)
I built these simple low cost but effective engine ears using similar stuff as the article shows, that I sourced from Radio Shack, here. They work. Clip the mic to a bolt or...on the side of the engine block near the frost plugs.
AutoSpeed - DIY Detonation Detection - Part 1
AutoSpeed - DIY Detonation Detection - Part 2
reference Radio Shack PN 33-1096