Knock is the biggest killer of performance engines out there, which is why having a high-quality knock detection system is important when you’re tuning any engine. We recommend using an audio knock detection system when you're tuning any engine. In this article, we'll showcase some popular aftermarket audio knock detection systems.
What is a Knock Detection System
A knock detection system in its most common form takes signals from a knock sensor mounted (where to mount a knock sensor) to the engine and allows you to hear these signals through audio headphones. This allows you to hear detonation/knock before it does damage to your engine. Some of these devices are very sophisticated and include digital processing to make the detonation/knock easier to hear. Sometimes audio knock detection systems are called knock monitors or detcans.
What is Knock and What Does Knock Sound Like?
Knock, or detonation as it’s also known, is an abnormal combustion condition that occurs after the spark has initiated combustion. As the flame front moves through the combustion chamber, the heat and pressure inside the combustion chamber will rise. In some instances this increase in heat and pressure can be enough to cause pockets of end gas (unburnt fuel and air) to auto-ignite or spontaneously combust. We recommend watching this detailed "Understanding Knock" video lesson (it’s free to watch if you enter your email) to get a better understanding of knock and its effect on the engine.
The video below gives a demonstration of what knock sounds like when listening through a knock detection device, in this case a Plex Knock Monitor system.
What to Look For in a Knock Detection System
When you're investing in a knock detection system it’s important to choose the right unit for your needs. Those needs will vary slightly depending on whether you're tuning professionally (lots of cars) versus tuning just one car.
When you're looking for a knock system, we believe it’s important to look at the following factors:
Ensure that the build quality is robust, especially if you intend to take it from car to car. Make sure the ease of setup is straightforward — some come with battery power which makes setup easier as you don’t have to hook up a power supply. Audio processing is another nice feature — this cleans up the audio; reducing noise that isn’t knock and enhancing noise that is knock.
Link KnockBlock
The Link KnockBlock is a USB rechargeable audio knock detection system. The KnockBlock takes signal from a peso-electric knock sensor and converts it to a signal that a tuner can listen to via headphones. It connects using two DTM three-pin connectors which go to knock sensor harnesses, and a typical donut style knock sensor.
Tuner Nerd Knock Monitor
The Tuner Nerd Knock Monitor Pro was created as a low-cost but high-feature knock detection system. This system is able to be connected to a laptop and allows the user to adjust settings, see a visual representation of knock, as well as listen to the audio. The system is very configurable and very advanced.
Phormula KS-Pro Audio Knock Detection Tool
Phormula has a few different models of knock detection systems available but its base unit, the Knock Analyser Pro (KS-Pro), is an audio knock detection tool that allows the user to listen for knock whilst tuning an engine. It’s bright orange and the case is ruggedized making it hard to lose in a busy workshop.
Plex Knock Monitor
The Plex Knock Monitor is a very high-end unit with lots of functionality built in. The build quality and audio processing are fantastic and it’s very configurable. This unit does take a long time to setup if you're wanting to use all that functionality though. This unit has been revised several times since filming the video below.
On-Board Knock Detections Systems
A lot of aftermarket engine management systems come with built-in knock detection and maybe even a knock control system. This is not to be confused with an audio knock detection system. We strongly recommend that you listen for knock using one of the standalone audio knock detection systems listed above, even if your engine management system has the ability to detect it.
Here are some tutorials about Knock Control on aftermarket engine management systems:
Link / ViPEC Knock Control Setup
