This is the 1st article of our new “Knock Detection Tips & Tricks” Newsletter that we will be sending out 4 times per year and which will cover insider tips for detecting knock the right way.
1.Always prefer the original mounting position as used by the OEM
If not available then find the next best position following the order of preference as indicated by the following diagram:
Position 1: in the center of the cylinder block
As used in OEM applications. Good balance of knock
signal pickup from all cylinders
Position 2: front or back side of the cylinder block
Reduced sensitivity to one or more cylinders depending
on position of sensor. Maybe somehow reduced signal to
noise ratio
Position 3: cylinder head
Reduced sensitivity to one or more cylinders depending
on position of sensor. Noise pick up from valvetrain.
Worst possible signal to noise ratio.
Position 4: intake manifold
Redused sensitivity overall
2. The mounting surface must be machined flat and square to the threaded hole or stud
It must also be at least 22mm in diameter. Why is that? Because a proper contact surface will ensure that the engine vibration will be transfered to the sensor reliably.
3. The mounting surface must be machined flat and square to the threaded hole or stud
It must also be at least 22mm in diameter. Why is that? Because a proper contact surface will ensure that the engine vibration will be transfered to the sensor reliably.
4. Make sure that the sensor mounting bolt or nut is torqued to the correct specification
The common M8 thread requires 20Nm torque.
5. Secure the knock sensor cable a few cm away from the sensor to prevent unwanted vibrations being transfered to the sensor
If any of the above is not adhered to, the acoustical coupling of the sensor to the engine will be compromised and the output signal of the sensor will not be reliable for knock detection!
© 2016 Plex Tuning.