Knock sensor
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Knock sensor
Does anyone know what the voltage output of the stock knock sensor is?? Maybe have a part number and make so i could get this info from the net?? I need to know is it a linear output??
Its a peizoelectric microphone.
Capacitive loading of 190pf
A 5 khz vib should give about 30 +/- 3 mV/g
main resonance is around 22khz on a CA18 and 18khz on an SR20
General impedance is about 1m ohm c= 280 +/- 50pf
Shunt resistor # 4.8 M ohm +/- 10% on newer versions.
Linearity from 5 to 15khz is usualy less than 15%
All the above can change with as much as a change of plug or wire,
Capacitive loading of 190pf
A 5 khz vib should give about 30 +/- 3 mV/g
main resonance is around 22khz on a CA18 and 18khz on an SR20
General impedance is about 1m ohm c= 280 +/- 50pf
Shunt resistor # 4.8 M ohm +/- 10% on newer versions.
Linearity from 5 to 15khz is usualy less than 15%
All the above can change with as much as a change of plug or wire,
Did you read what I just posted?
I thought you were a mech engineer? Sorry, maybe I got you confuzed with somone else
wouldnt be the 1st time 
Its a Peizo microphone, so yes it will generate a tiny voltage at certain vibrations as the crystals excite, usualy around 3mv @ 5hz, as a base line, they change with age so youll need to back probe it and check, youll have 2 wires, one will be ground, other will be output, dont expect big numbers they will be TINY, use a wave scaner if you want to be lekke accurate, or better yet buy a nice new sensor and get the white paper on it.
Remember the bolt and location of the sensor will make more difference than any mess up you could make in ure sum's trying to get it to work, so use the right tensile strength and correct thread length bolt to make your life more simple or the ramp of the hz vs. mv will change away from spec at 15% odd...
GAWD i feel like im still sitting at work
I thought you were a mech engineer? Sorry, maybe I got you confuzed with somone else
wouldnt be the 1st time Its a Peizo microphone, so yes it will generate a tiny voltage at certain vibrations as the crystals excite, usualy around 3mv @ 5hz, as a base line, they change with age so youll need to back probe it and check, youll have 2 wires, one will be ground, other will be output, dont expect big numbers
they will be TINY, use a wave scaner if you want to be lekke accurate, or better yet buy a nice new sensor and get the white paper on it.Remember the bolt and location of the sensor will make more difference than any mess up you could make in ure sum's trying to get it to work, so use the right tensile strength and correct thread length bolt to make your life more simple or the ramp of the hz vs. mv will change away from spec at 15% odd...
GAWD i feel like im still sitting at work
Gary, tip,
Ok, dont stress that much about being spot on with a knock sensor mv, you have way to many veribles to inpact the output of it, get in a good spot on the block, pref central between centers and as high up on the block as you can, on clock direct motors put it on the aft face, IE nissan motors in the intake side, as high up on the block as you can,
Hook it up to your device your going to monitor it with, up your timing at 2500rpm to about 55-60deg, and load it real fast just for an instant, record your mv at the first audible det, then back that timing off to normal, use that at your 100% limit, set the car to run around 30-40% as ure highest value to not pass.
Ok, dont stress that much about being spot on with a knock sensor mv, you have way to many veribles to inpact the output of it, get in a good spot on the block, pref central between centers and as high up on the block as you can, on clock direct motors put it on the aft face, IE nissan motors in the intake side, as high up on the block as you can,
Hook it up to your device your going to monitor it with, up your timing at 2500rpm to about 55-60deg, and load it real fast just for an instant, record your mv at the first audible det, then back that timing off to normal, use that at your 100% limit, set the car to run around 30-40% as ure highest value to not pass.
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Vlade
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Gary here is a way to detect a knock DIY style... it might not be accurate it serves no purpose other than indicating kak is going to happen any second now. 
I guess one can use it to trigger the Wolf to switch to a map with retarded timing but then you would need that memory module for the Wolf.
http://200sx.za.net/phpBB2/viewtopic.php?p=22673#22673
I guess one can use it to trigger the Wolf to switch to a map with retarded timing but then you would need that memory module for the Wolf.http://200sx.za.net/phpBB2/viewtopic.php?p=22673#22673
Hairdresser MX5
Oh sorry man I didnt read where you said the voltageDid you read what I just posted?
I thought you were a mech engineer? Sorry, maybe I got you confuzed with somone else wouldnt be the 1st time
. I am a mech engineer, so I know how the thing works as well.I was asking because I was reading about some of the Bosch sensors and they give out 0-5v reading which logic makes me think that it is more accurate that reading mv, not because of the higher voltages but beauce of the greater scale.
Do you think the stock sensor position is good enough??
I want to use the Zeitronix to datalog the voltage output of the sensor just not sure if it will read millivolts, any ideas??
Rezlo, have you ever used a set of DET cans?? They simple to make but how clear is the sound, I would amaging you will pick up every little vibration and rattle?!
