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det_can_setup [2015/03/24 13:01]
shelgame
det_can_setup [2015/03/24 13:07] (current)
shelgame
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 A handy tool for tuning ignition timing is a Det Can - A detonation listening device. A handy tool for tuning ignition timing is a Det Can - A detonation listening device.
  
-This writeup will focus on using the Bosch/VW Wideband ​Knock Sensor ​and a simple microphone amplifier from Radio Shack.+When tuning our ECU's for ignition timing, a common problem is setting up the knock threshold so that it detects knock accurately. When the engine and/or calibration is significantly modified, the factory knock threshold may no longer be accurate for detecting knock. A Det Can allows you to actually hear the sounds of combustion. When knock is happening, it is a very clear '​bad'​ sound. And, as a result, the knock threshold can be adjusted accordingly. 
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 +This writeup will focus on a DIY Det Can using Bosch/VW Wideband ​knock sensor ​and a simple microphone amplifier from Radio Shack.
  
 Parts you'll need: Parts you'll need:
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   * Ear buds or headphones   * Ear buds or headphones
   * A laptop, if you want to record the engine sounds for later analysis   * A laptop, if you want to record the engine sounds for later analysis
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 +The VW/Bosch wideband knock sensor has an output that is compatible with microphone voltage levels. So, it's output can be directly sent to any microphone level input. I would caution against using the signal directly into a PC microphone port as there is a possibility to damage the port input. Instead, use a microphone amplifier with a volume control on the output (such as the suggested Radio Shack unit).
  
 First, you'll want to add length to the wires coming out of the knock sensor, and install the microphone jack onto them. You'll want the wires to be long enough to reach the drivers seat, where the amplifier will be located. This will allow you to listen for knock while driving. First, you'll want to add length to the wires coming out of the knock sensor, and install the microphone jack onto them. You'll want the wires to be long enough to reach the drivers seat, where the amplifier will be located. This will allow you to listen for knock while driving.
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 +Finally, connect your headphones (or PC microphone input) to the headphone output on the microphone amp. Now you're ready to listen for knock.