Knock can be defined as the spontaneous ignition of portions of the mixture, before being reached by the flame front. 


The effects of prolonged knock are extremely serious and include, but are not limited to: blown head gaskets, holed piston crowns and engine seizure. 


As this is not intended to be a guide on how to tune, but rather how to use the ME ECUs to apply existing knowledge, we won’t go into too much detail about why knock occurs and how it can be prevented, although some of the factors that determine detonations are: high ignition advance, incorrect combustion chamber temperature management (high Exhaust Gas Temperatures, improper cooling etc), low-octane fuel and high compression ratios (static or through forced induction).


The ME-range of ECUs feature an advanced Digital Signal Processor that allows the ECU to filter out a lot of the background noise made by the engine, greatly enhancing the ability to detect knock at higher RPM. 


Please be aware that, as with all knock detection systems, this is a “reactive system”, meaning that it can only detect and try to prevent knock after it has occurred, its role being to complement a good tune and guard against unexpected conditions (very high ambient temperatures, part failures), not act as some form of auto-tune for ignition advance. Install a standard Bosch Knock sensor as detailed here.


On Firmware 3.9 and later, we have added per cylinder knock levels. These are a series of DROs, which represent the number of knock events recorded on that cylinder, as well as the highest peak value per cylinder.


See Sensor Types, Knock Settings and Setup procedure.