DIY knock detection, how?

[GreenV8S]

As far as I understand it, knock detection systems typically consist of a piezo microphone bolted to the block, a band pass filter and some sort of adjustable level detection circuit, all built into the ECU.

What I want is a standalone version that can be fitted to a vehicle that doesn't have the necessary smarts built into the ECU. Either just to display a 'noise' reading that I can look at during testing, or ideally with some sort of alarm output. I've found a couple of people selling diagnostic units for around £250, look like they're aimed at dyno operators rather than something intended to fit a car. Is there a better solution?

[GreenV8S]

Eh? What's that you say? Speak up would you?

[GreenV8S]

Thanks for those links.

I've looked at the MegaSquirt info a couple of times and keep coming away unsure whether it capable of doing all the things I need. For example there appear to be multiple hardware versions but the Extra features that the knock detection system is built on don't work on the newest hardware?

Is there an advocacy forum or other resource where I can find out which (if any) MegaSquirt solution fits my problem? (essentially 8 cyl sequential FI, mapped ignition, mapped WI, dual lambda control)

[GreenV8S]

The link system looks very interesting and I may well give it a try. These systems all seem very expensive though given that one 'bar' from a graphic equaliser display does more or less the same thing.

[GreenV8S]

Does it work, come on you've had nearly an hour to play with it!

What knock sensor are you using with it? (Anyone recommend a source for knock sensors?)

[GreenV8S]

That picture of the knock detection doohicky has what looks like a mini timer connection, aka Bosch injector type connector. Does the Lucas knock sensor you mentioned match that?

[GreenV8S]

I assume that sort screws into the block somewhere, but only if you have the correct hole tapped. I've seen pictures of a slightly different sort which have a hole in the middle, presumably designed to be bolted on somewhere. Any idea what these would be off?

[GreenV8S]

By following the links in this thread I've found a couple of part numbers for the holy sensors:

Bosch 0-162-231-001 Peugeot 505 Turbo #5946.03
Bosch 0-261-231-046

Both these appear to take the mini-timer (Bosch injector type) connectors. The top one looks similar to the ones that the aftermarket kits are shown with, I don't know if there are any differences in fitment or performance.

I haven't seen any prices for these particular sensors but other similar ones seem to cost from £80 upwards, so £15 seems like a good price if it works.

[GreenV8S]

I've got one of Boris' knock sensors on order too. As it's essentially a microphone, I guess it would be possible to reduce the sensitivity by putting a small resister in series? There's probably a more elegant solution involving changing filter components etc but I like to try the simple approach first ...

[GreenV8S]

Perhaps it would be possible to look for a rate of increase of noise rather than any specific noise level. I guess that's what the trained ear would do?

[GreenV8S]

stevieturbo said:

Bosch sensor that comes with the Knocklink is 0 261 231 006 Single 8mm hole with 2 pin mini timer plug.

I've got one of these on order, £30 from my local Bosch agent. I was afraid it was going to be quite a bit more than that.