Knock sensor tool to measure detonation

[Dynamohum]

Has anyone used a knock sensor, as a tool to confirm there is no detonation going on after their engine modifications?

Looking at the possible use of ceramic coatings for pistons, combustion chamber, valve surfaces, exhaust port, and headers. To reduce the heat transfer thereby reducing the likelihood of detonation. I’ve done a fair bit of research on the propagation of the ignition kernel and causes of detonation. Unfortunately the early stages of detonation is often inaudible and can still cause extensive damage in a short time. So to be safe I would like to be able to measure it if present.

Thanks, Paul

[sjf911]

I have added a knock detection module to my megasquirt setup ( http://www.viatrack.ca/ ) on my NA 3.2ss. My detector is on the case while the 964 used a detector attached to a metal bridge across the cylinders. So far, I have not had detectable knock issues on 93 octane and low winter temperatures. However, I am in the process of starting a turbo conversion. This will be the real test.

[Dynamohum]

Thanks for the link Steve, it looks like this module would do the job. Where on the case did you mount your knock sensor?

[sjf911]

I mounted the sensor on the oil breather plate which was recommended by "Knocksense".
I drilled and tapped the empty "bung".










The Knocksense unit is wired into the wiring harness for my MS-II.




And the LED warning light fit perfectly into the Ox sensor warning light holder on the dash after popping out the OEM lens.

[JohnJL]

Picture # 16 on this post shows a detail of my knock sensor installation, using a 993-style bridge across the 1-2-3 cylinder bank.

Other stuff there might interest you like piston coatings...enjoy!

Supercharged Race Car Build

[WERK I]

Originally Posted by sjf911

I mounted the sensor on the oil breather plate which was recommended by "Knocksense".
I drilled and tapped the empty empty "bung".

Really? That is kinda of a surprises me. That area is isolated, somewhat mechanically, by the paper gasket between the breather cover and the case. Maybe it dampens the lower amplitude mechanical noises from the "ping" so you get fewer false positives?

[sjf911]

After looking over the case extensively, I came to the conclusion that it was also the safest place to locate the sensor. I don't know what effect the gasket would have other than damping "ring". The bolts that clamp the cover should be more than capable of transmitting the acoustic signal. The Knocksense control unit does have a potentiometer for adjusting sensitivity and is supposedly tuned to the detonation frequency distribution.
Obviously mounting the sensor on the case prohibits identification of individual cylinder detonation which is the advantage of mounting dual units on bridges over the cylinders. MS-II on the other hand has no provisions for individual cylinder knock identification and ignition control.

[WERK I]

Thanks Steve, I look forward to hearing more about your MS-II results.

[dsiegel360]

knock sensor

An entertaining thread.