For all you forced induction guys.

[sciroccos at earthlink.net (Jim Ruffi)]

I have a couple thousand piezo transducers here if anyone wants to play with
this project, assuming it calls for round brass disc-type ones with silver
over a quartz substrate.  I have a couple of different sizes: 25mm and a
smaller one.

I also have/had these encased in a plastic housing "pickup" assembly, but I
threw out about 4000 or so of these a few years ago.

Jim

----- Original Message ----- 
From: "Dan Bubb" <jdbubb@verizon.net>
To: "Scirocco List" <scirocco-l@scirocco.org>
Sent: Monday, July 11, 2005 12:45 PM
Subject: For all you forced induction guys.


> About a year ago I bought this little audio amplifier kit, a piezo crystal
> and a set of headphones to construct a DIY audio knock detector that I
read
> about on www.autospeed.com.
>
> Basically you glue the piezo crystal (converts vibration to a voltage
output
> or converts a voltage input to vibration) to a clip that you can clip onto
> your engine block.
>
> Well, I finally got off my dead ass and built the kit. The circuitry
itself
> was nothing, the board is ~1.5" x 1" with 8 components. What took all the
> time was mounting all the bits in a box.
>
> Finally tested it this weekend.
>
> It really works. Mostly you just hear a lot of things clattering around in
> there.
> But, pinging/knock is a clearly detectable hard ticking sound.
> So, as you're hauling ass down the highway despite lots of wind noise,
lots
> of road noise, lots of engine and exhaust noise, you can still clearly
hear
> the
> engine pinging.
>
> Interestingly, after you shut off the engine from idle, you can also hear
> the ball bearing turbo spooling down for 20 seconds or so!
>
> Anyway, for about $50 and a few hours of assembly time this rates right up
> there
> with a WB-O2 as a tuning tool to have for forced induction engines.
>
> Dan
>
>
>
>
>
>
>
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