Detonation Plug Sensor

The plug mounted detonation sensor uses piezo technology to detect pre-detonation of the fuel; this is especially dominant on unleaded fuels.

The detonation causes a deformation of the head/plug and this mechanical shock is detected by the sensor and converted to an electrical signal.

This graph shows the effect of a long straight High RPM with full throttle on a Honda RS125

Use a detonation plug with a longer reach ( 3mm longer )
The plug must not use a compression/crush washer
Space is required around the plug for the sensor – inset spark plug holes (i.e. air cooled engines) are not usually suitable.
Copper washer under or on top of the sensor but don’t use on both sides
Tighten to 25N/m – any tighter will damage the unit
Don’t stress or clip the cable tightly
Delicate sensor treat with care
On most logging systems and ignitions the system will not detect unless the engine is running
Always route the cable away from the high voltage spark plug lead as this can cause false readings
To test, remove the detonation ring, attach to a separate head and plug, tighten to 25N/m and place a 16mm socket over the plug, run engine - tap socket sharply with a small nail/penn hammer
Excessive detonations could indicate a stuck / trapped ring or the piston touching the head
If left unconnected the detonation ring can detect ignition pulses - join the two inputs together to inhibit.

Price: £245.00