Phormula KS-4 Knock Monitoring Tool

The revolutionary Phormula KS-4 Knock Monitoring Tool is our most advanced knock detection system. Offering all the great functionality of the KS-3 in addition to a fully configurable 0-5v output and a remote alarm function allowing the KS-4 to trigger an external warning system.
* Complete kit – Includes sensor and 3 metre sensor cable.

£295.00 (ex VAT)


The Phormula KS-4 Knock Monitoring Tool contains all the advanced features of the Phormula KS-3 plus:

0-5v Analogue Data Out

The KS-4 contains a true 0-5v analogue data output. Data output rates are configurable at up to a blistering 100 samples per second and fully compatible with all Data Logging Software, Engine Dyno’s, Rolling Roads and ECU’s. The 0-5v output can be integrated with an ECU to provide closed loop knock control.

Phormula Knock Datalogged

External Trigger

The Phormula KS-4 external trigger function adds further flexibility by allowing you to trigger your own external warning device when knock is detected.

This may be something as simple as an LED warning light or triggering a knock strategy in your ECU.

Engine Wiring Loom

How does it work?

The Phormula KS-4 monitors engine knock levels and can be configured to alert the driver via a visual, audible or external warning device. The KS-4 can be used as a hand-held device or permanently mounted to the dashboard and is configurable for frequencies between 6 and 9 kHz. This system includes high quality Bosch Wideband Knock Sensor, Sensor Plug, Shielded Signal Cable, Mounting Kit and Wiring Loom.


The KS-4 Knock Monitoring tool has been designed to be very quick to install and comes as a complete kit containing everything necessary for the installation. A high quality Bosch knock sensor is included which is linked to the main unit via a shielded signal cable. Installation is very simple: Mount the sensor, connect the signal cable and connect the power supply.

What is Knock?

Knocking or detonation occurs when unburnt fuel in the combustion chamber explodes instead of burning in a controlled manner. When engine knock is occurring, the pressure in the combustion chamber rises dramatically to levels that can destroy engine components in a few seconds.

What does engine knock sound like?

See our video clips demonstrating our products in action clearly detecting engine knock. Towards the end of the demonstration there is an audio sample of knock.


The KS-4 Knock Monitoring tool is very simple to configure. The most common question we are asked is “What frequency should I select?”. We now have an online calculator that will estimate the knock frequency for you. Use our Knock Calculator to estimate the knock frequency of your engine.


“The development of the new KS-4 has been a welcome addition to the Phormula product range. Coupled with an ECU with an analogue input, it has enabled accurate logging of knock events that mean we can correlate those events with those heard on the det cans.”

Paul Blamire – Zen Performance

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