Knock Sensors - using V6 on V8

[yoda69]

I was looking around on eBay for a V8 knock sensor and memcal with knockboard and noticed a few guys selling kits.
I sent a couple of the messages for more info and was advised that the knockboards they are selling for the V8's are actually off a V6.
Surely if they were the same Holden wouldn't have needed different codes on the knockboards for a V6 and V8?
What are peoples experience with this?

Thought it was worth a topic, as these guys appear to be selling a heap of them and sooner or later members on here will end up with somebody bringing a car in with 1 fitted.

Thanks,
yoda69

[Jayme]

I have tried a v6 knock board myself on a turbo v8, I eventually figured out that the massive power loss was bloody false triggering, the v6 filter just triggers at random times for no reason at all.

[antus]

the filter is actually an audio filter, and the sensor is a piezo microphone. The filter only allows the sounds of knock through and they are tuned to the engine. They wont work on a different size engine with different number of cylinders. Typical ebay sellers!

[yoda69]

Further to this, would be nice to identify what knockboard comes from what.
What I've seen the code on the back of the knockboards so far are:

1H on VN/P V6's
1U on VR V6's
1F on VR V8's

If anybody has any others, let me know, as it maybe worth adding some info into the memcal area.

Thanks,
yoda69

[Dec_head]

This post has some other info https://pcmhacking.net/forums/view ... 6&start=10

[delcowizzid]

there are so many filter boards 1h vn 2h 3h ive seen in vp i have 2 BABR memcals here one has 2h2029 filter other has 3h2074 filter vr normally 1U

[Holden202T]

i will hopefully be getting my hands on a vs v8 with knock on it today or tomorrow so i'll be able to add that info shortly

[vnsswithcam]

wonder how hard it would be to make your own knock filter boards ? has anyone looked into that?

[Holden202T]

looks like the VS V8 one is the same as the VR, 1F5238

[fabmec]

I have used a V6 knock board on V8's before with varying results, mostly alot of false knock counts, but it still hears bad knock and pulls timing as well. I still have V6 knock board fitted to a turbo 355 stroker in my 80 series, it is turned off because of false triggering but I do use it if we are travelling in the outback as fuel quality can be an issue. I would like to try a V8 knock board to see the difference but unfortunately I don't have one, as running knock control in certain conditions is a good thing.
An adjustable knock filter as far as i can see would also be a really good thing. The following is just a bit of info if anyone is interested.

The knock board is a band pass filter and buffer. It filters the sensor response (just a piezo microphone) and turns it into a buffered 0-5v signal - the output is 5V=no knock and 0V=knock, it may be higher than this but the ECU circuit clamps it to 5v internally. Inside the ECU the knock sensor is connected through an inverting buffer and to a counter pin - 16 'knock counts' are = about 1mS of knock. From memory only the four legs together at one end are used for the circuit the rest are just standoffs, but I could be wrond on that.
Oh and the frequency the filter is tuned to is mostly dependant on bore size.
Detonation Frequency
The reverberation resonance generated by detonation generally lies in the range between 2 and 12KHz. The following equation can be used to estimate the detonation resonant frequency for a specific engine.

Detonation resonant frequency = 900 / (3.14 x cylinder radius)

If you listen on the dyno thruough headphones with a mic clamped to block, over the clatter of pistons, valve gear, explosions and gearbox whines, detonation sounds like a sharp "splat!, splat!".

Hope that helps.