DIY knock detection, how?

[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?)

[stevieturbo]

scrap yard....virtually every new car over the last 10 years or so has one.

Although any Bosch outlet should be able to source new ones. I think they start at about £30 upwards.

[eliot]

Visited local motor factors, looked for volvo/saab one - ended up with one from a 1995 ish Renault espace Lucas part number SEB191 - £15 quid.

Works a treat (tapping it on the side of my bench power supply!), will do a little video later (on the phone right now!!)

Just checked my paypal, Cost was £41 inc shipping.

>> Edited by eliot on Friday 8th July 17:30

>> Edited by eliot on Friday 8th July 17:33

[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?

[eliot]

Here's a photo of the sensor, it does indeed plug straight into the supplied connector (timer connector)



Grainy camera phone video of it working: (will run on realplayer)

[url]<a href="http://homepages.nildram.co.uk/~eliotmez/knock.3gp">http://homepages.nildram.co.uk/~eliotmez/knock.3gp</a>[/url]

Going to bolt it up to me turbo chevy lump tommorow!

>> Edited by eliot on Friday 8th July 18:45

[stevieturbo]

The rectangular Bosch plug, is fairly common everywhere. I have a couple of Lucas knock sensors of a RV8, ad they use the normal 2 pin mini timer.

[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?

[stevieturbo]

Ive seen a 1.0 3cyl Corsa engine with that type, so I imagine some other vauxhalls will to..

A Subaru also has that type, although it doesnt have the mini timer plug.

The Knocklink comes with a Bosch knock sensor with a hole in it...although I dont have one handy to get a part number.

[eliot]

Yep, all the photo's of them Ive seen are the bosch ones with a hole in them. This one seemed good value, so I went with it.
Its bound to be a metric thread on it, so im going to tig a metric nut on top of a unc bolt and bolt it into the back of the cylinder head and see how it goes.

[stevieturbo]

The Lucas ones I have for the RV8 are defo not metric thread. I'll look later, but I think they are about 7/16" UNC

[eliot]

Its from a Renault, so i assumed metric. Not sure what it was, couldn't find a nut that fitted exactly (metric or english) - found a close one on though and tigged it to a bolt.

I was going to fit it to the cylinder head, but i was worried about the heat, so i bolted it into the inlet manifold. I'll try some other locations.

Just revving the car up in the drive would make it trigger despite adjusting the sensitivity. So might have to find a bosch sensor, that the knocksense it built around. Plus it would make fitting easier.

[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.

[stevieturbo]

Bosch sensor that comes with the Knocklink is 0 261 231 006

Single 8mm hole with 2 pin mini timer plug.

[leorest]

I haven't read all through this thread but the following link seems to be what you are after
Leo

www.replica-cobra.co.uk/accobra.htm
Click on Knock detection in the left hand pane.

[eliot]

leorest said:

I haven't read all through this thread but the following link seems to be what you are after Leo <a href="www.replica-cobra.co.uk/accobra.htm">www.replica-cobra.co.uk/accobra.htm</a> Click on Knock detection in the left hand pane.

Yep, that's phil ringwood. He wrote the Knock detection part of Megasquirt (that i'm running)
He posted on the first page of this thread.

Ive updated my web page with my findings with the KnockSense unit:

www.mez.co.uk/turbo7.html

(Scroll to the bottom)


>> Edited by eliot on Tuesday 12th July 17:29

[daxtojeiro]

leorest said:

I haven't read all through this thread but the following link seems to be what you are after Leo www.replica-cobra.co.uk/accobra.htm Click on Knock detection in the left hand pane.

Thats me
Phil

[eliot]

Phil,
What sensor are you using, how much was it, does it work ok (mine triggers like mad over 3.8k) and where did you put it?

ELiot.

>> Edited by eliot on Wednesday 13th July 07:25

[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 ...

[stevieturbo]

eliot...could it be triggering like mad because it is actually hearing things ??

Thats the problem with most of the electronic devices. Sometimes they pick up false knock, and you get kinda paranoid about it.. The earphone/det can method is supposed to be the best, as your ear/brain does the filtering.

Must get around to making a set myself. My Knocklink using the LS1 sensor is very very sensitive. With the std engine, I believed it. With my new engine, I'm not so sure. it was lighting up like mad, but I couldnt audibly hear anything, and I'm usually pretty good at picking it up. Having said that, I did pull a lot of timing out, and it has quietened down the sensor.
But it makes me think, if it was actually that far advanced in the first place, it should have been detonating like crazy and you would hear it.
But I couldnt ?

[Pigeon]

GreenV8S said:

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 ...

Not a series resistor - a potential divider would be a better bet. A volume control. The two outer terminals go to the knock sensor, the middle and one outer go to the box of tricks. I would guess that the knock sensor may be a piezoelectric device so will have a high output impedance so you'll want a large value volume control - say 250k or so. You can check, though, by measuring the resistance across the knock sensor terminals. If it's piezoelectric you'll measure an open circuit. If you measure a resistance of a few k it's probably electromagnetic and you want a volume control of the same order of resistance that you measured.