What is closed loop knock control?
Closed Loop Knock Control is arguably the most important feature on a road car ECU. Given the variability of pump fuel in the UK, the amount of detonation an engine will experience on different tanks can vary considerably. An ECU equipped with knock control will listen to the output of the knock sensor and retard ignition timing until no more detonation is sensed. The OEM JECS ECU will also richen the mixture and reduce boost pressure if significant detonation is heard. An aftermarket ECU without this facility relies on every tank of fuel being exactly the same as the one it was mapped on or has to be mapped with a safety margin, costing power. Owners of knocklinks will know that activity between tanks of the same type of fuel can vary significantly, which is why knock control is one of the most important features of an ECU. It is very rare for aftermarket ECUs to offer it, even as a cost option.
