Using a knock sensor from one engine on another

[Bruce]

The bottom line is that the acoustic ones just listen for noise, and you
have a slightly better then 50/50 chance of hearing it anyway.  Set it so
that it reacts to all detonation, and any harmonic will set it off at some
other time.
   They are a tuning aid, no more no less, put all your eggs in one basket,
and yada yada.
Most of the oem cals are for 2,400-3,200 rpm anyway.
  I played mix, and match just using some junkyard stuff till I got the
response that I wanted
Bruce




From: "Eric Fahlgren" <efahl at adams.com>
Subject: Re: Using a knock sensor from one engine on another


> TVS wrote:
> >
> > I assume the frequency has some dependence on variables
> > like bore diameter and combustion chamber shape, but is the knock
detection
> > circuitry likely to 'listen' for a wide range of frequency's or just a
> > narrow band?
>
> I don't think bore has much bearing.  I've always thought that the
> bore was a single variable in the excitation function, but that the
> response frequency was determined by the structure (i.e., the block/head
> et al).  Imagine a 10 oz hammer ringing a bell whose principal mode is
> 100 Hz.  What do you hear?  Mostly 100 Hz.  Strike the same bell with a
> 10 lb sledge.  Still pretty much the same response.
>
> Here is some info (resonant frequencies of knock sensors) that will
probably
> be of interest to you:
>
>    http://acc-electronics.com/cloud/images/page3_55.jpg
>
> Check the second and fourth columns of the table at the bottom.
> It looks to me like there isn't any correlation between the
> knock sensor's frequency and any of the obvious engine parameters
> like bore and stroke (but then again I didn't do any real analysis).
>
> --
> Eric Fahlgren                            Mechanical Dynamics, Inc
> efahl at adams.com                          Ann Arbor, Michigan, USA
> --------------------------------------------------------------------------
--
> To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the
quotes)
> in the body of a message (not the subject) to majordomo at lists.diy-efi.org
>
>

----------------------------------------------------------------------------
To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org