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 Post subject: knock monitoring!
PostPosted: Fri Jan 10, 2003 11:29 am 
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CSM Junkie
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Joined: Sun Jan 20, 2002 7:00 pm
Posts: 767
Location: Montreal, Quebec, Canada
ok ive been playing with the diy a/f meter (wich works better than the autometer by the way) and now im starting to play with shift lights...


and the two wires in my brain shorted....

tell me what you guys think..

if the knock sensor sends information in hertz to the ecu, logicaly a frequency to voltage converter chip would get us a voltage..... and if this voltage is read by the voltage analyser from the diy a/f meter we could get a display of how much knock we have.... hummm interresting isnt it?

but i think we would need to put a audio amplifier in order not to drop the signal from the knock sensor

just my two cents...

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 Post subject:
PostPosted: Mon Jan 13, 2003 12:30 am 
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Some call me a god

Joined: Sat Jan 19, 2002 7:00 pm
Posts: 1524
Location: Denton, Tx
yes, but, theoretically you can install an led (they can run on VERY low voltage and last forever) jsut off of the voltage from your knock sensor, the sensor developes its own voltage froma piezo-electric crystal the mnore severe the knock, the more often and higher the voltage, if its enough voltage to light a lighter, than its enough to trigger an led, and not be confused by the boost control solenoid, as soon as you have a light shine, you know you have knock....easy

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If speed kills, then i shoulda been dead awhile ago. There is no such thing as "Too Much Power". There is no excuse for a lost race. Do you view the rev limiter as a fun limiter?or as a shift point? And we all know, more boost=more fun.


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 Post subject:
PostPosted: Mon Jan 13, 2003 10:01 am 
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CSM Junkie
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Location: Montreal, Quebec, Canada
i know what you are talking about craker, but i thought a light could not be pluggeddirectly on the knock sensor, and the reason why is i think because the knock sensor is like a microphone, recording for all the engine noises and the ecu will filter this info to look at a certain frequency band wich is determined to be the knock. .. i saw a formula on the net to calculate the frequency acording to the cylinder diameter and all other dimension.

So my idea would be to filter the sound from the knock sensor withe capacitors and plug it into the system i was talking about up here.


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 Post subject:
PostPosted: Mon Jan 13, 2003 11:44 am 
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Some call me a god

Joined: Sat Jan 19, 2002 7:00 pm
Posts: 1524
Location: Denton, Tx
that sounds like a gerat idea, lemme know if it works wouldya?


also, are you just intercepting the signal from the knock sensor to the ecu altogether?
or are you supplementing it?

ideally we don't want to make the signal stronger, as it will cause the ecu to back off more timing, until we have no power whatsoever, and no knock of course.

but try it, i would like to see how it all comes out,

_________________
If speed kills, then i shoulda been dead awhile ago. There is no such thing as "Too Much Power". There is no excuse for a lost race. Do you view the rev limiter as a fun limiter?or as a shift point? And we all know, more boost=more fun.


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 Post subject:
PostPosted: Mon Jan 13, 2003 12:00 pm 
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CSM Junkie
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Joined: Sun Jan 20, 2002 7:00 pm
Posts: 767
Location: Montreal, Quebec, Canada
this is what i meant by amplifying the signal, because if i tap it off the ecu signal im affraid ill steal the power, so if i use a diode from the ecu signal and i amplify it after it should be allright.

ill try that in the few next weeks


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 Post subject:
PostPosted: Mon Jan 13, 2003 1:16 pm 
Since the knock sensor is so critical to "safely" getting the post power from these cars, I would be VERY hesitant to hang a load off of it. It would definitely have to be a high impedance load so as to disturb the signal as little as possible.

Go to http://www.autospeed.com and do a search on DIY detonation detection. There are some good "audio" solutions to this.

They use an amplifier and a set of head phones. I think it would be cool to use the cars speakers instead of the headphones... :)


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