Knock Box Talk

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Holden202T
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Knock Box Talk

Post by Holden202T »

After seeing the stuff in other threads about knock boxes I thought I'd create a separate thread for them, to get all the info in one spot and so it doesn't clog other peoples threads with it.

The original article posted was this http://www.autospeed.com/cms/A_1353/article.html

so I thought that might be a fun project that I might actually get some use out of! so I went to jaycar and bought all the bits! well almost all of them.

my plan was to use it with a Alloytec V6 knock sensor as I have one lying around that I had planned to use for years!

so after assembling the kit and getting it all fitted into the box (well almost) I found a spot to mount the sensor and gave it a bit of a test!
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so im not too sure how good of a spot it is for the sensor location, but it was quick and easy for a test, theres not a lot of good locations on a holden 202 with the right size bolt hole to suit the sensor.... but im going to try and sort out something more long term and in the middle of the block on the other size where I think there is a good option.

it all seems to work ok, you can definitely hear a ticking sound which i reckon is the injectors, and theres also a dodgy lifter in there I reckon hehehe .... the motor by best guess is a high milage stock 202 so im not expecting it to be the best, although it is reasonably quiet running for its age!

anyways I took a little recording of the sound that I get out of the knock box ... interested to see what others who have used these have to say

[youtube]http://www.youtube.com/watch?v=ONvbnCYIE8E[/youtube]
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Gareth
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Re: Knock Box Talk

Post by Gareth »

Nice job :thumbup: i had the same idea about a seperate thread too but lack the time

On the hardest rev you give the engine you can hear the very start of knock. The best description i have used to describe knock is 'nails hitting a tin roof', first you hear a couple of nails as knock begins, then as it sets in you hear many more until it sounds like a down pour.

This is a must have tuning tool
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Re: Knock Box Talk

Post by vlad01 »

You can hear all kinds of sounds. There is a sound of exhaust pulses reverberating in the runners that sounds almost identical to knock.

You cant hear it on stock cast manifolds, but certainly do on long runner extractors. Its like a metallic popping sound with consistent rhythm.


Regarding the sound of knock. I reckon it sounds like popcorn going off in a metal pot. With the same sporadic rhythm as popcorn.

Externally I have heard major knock on my sisters XD ute and it sound like someone crinkling thick gauge tin foil.
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The1
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Re: Knock Box Talk

Post by The1 »

nice, pretty sofisticated, ive just used a $5 headphone amp off ebay lol Get a stereo one and wire both banks one each side
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Re: Knock Box Talk

Post by vlad01 »

With the professional knock box there are band pass filters and processing to reduce unwanted noise and let through typical knock frequencies.

Using just an amp to make a home brew one will work but harder distinguish the sounds as everything is normally let through.
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Holden202T
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Re: Knock Box Talk

Post by Holden202T »

I'm not surprised at any noise that comes from this thing hahahah .... its a stock 202 put in the Gemini, turbo and all manifolds bolted on and running methanol :P

I've fiddled with the idle part of the tune but other than that its just what I had in it with the worked motor, so the timing maps probably far from right, but then its also probably 9:1 comp with methanol so its certainly not pushing the limits!
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Re: Knock Box Talk

Post by immortality »

I like it :)

Could this be adapted to work with VL400's data logger?

edit:I just remembers Festy's thread about his knock board, that would probably be more ideal for use with the datalogger?
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Re: Knock Box Talk

Post by Holden202T »

yeah this is purely an audio device, if you wanted to connect my above pictured sensor to a knock filter and log it then something like festys is the go!

I think I've found a good spot on the block to mount the sensor too, if I helicoil the hole it should then be the right size for the bolt that fits the sensor! and the spot is cast right into the side of the block near cylinder 3/4 so hopefully be a good solution!
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Re: Knock Box Talk

Post by immortality »

YEah, something like this is definitely a must have, my friend wants to see if we can get more timing into his 355 but I'm hesitant without some way to monitor knock. Running 28° now, it can probably handle more as it's not a high comp motor but better safe than sorry.

I have PM'd Festy about his knock board :)
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Re: Knock Box Talk

Post by vlad01 »

Does his knock board have audio output?

Would be awesome if it does after the adjustable band pass.
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