Knock detection system
Turbo Mini Forums

Does anyone have any experience of these on an A?I've read some comments in the archive but no clear guidance there.Thor engineering have a system called Knocklink.

'Where does the engine go?'

What do you want to do with it ?

If its just something to plug into your ears and listen....then copper tube bolted to the block, then rubber hose into a pair of ear defenders is as good as most.

For electronic trickery.....the Phormula Knock Analyser Pro is much better then the Knockblock, and also easier to install ( ideal for car to car use too )
Also far better quality than the ink stuff.
Phormula do a visual/audio display and warning device to. I have one, but havent used it yet.
It is also of excellent quality.

I have the knockblock on my own car, and it works ok. I only chose it for its 0-5v logging output. Ive yet to see detonation on this, but its very difficult, as there are lots of spikes on the log. I cannot hear any detonation, so Im sure its just noise.

Filtering is the problem.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

i have a turboxs knock lite .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=2563

I plan to use this as a warning light,so that having set up the engine on the RR,I can see any det before I destroy the engine (again!).Hopefully I could calibrate it when on the RR.
Thanks for the link,Rob,I read this before but there didn't seem to be any followup on whether it all worked.

'Where does the engine go?'

Hi,
I've not heard of anyone using one on an A series until Robert posted.
I plan to, but it will be integrated into the ECU.
As Stevie says, the filtering of the sensor signal is the important part, mine uses a bandpass filter to cut out the noise either side of the det frequency.
Cheers,
Gavin :)

Edited by Bat on 6th Jul, 2008.

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Robert,What's your experience with the Knocklite?Did you have a filtering problem/

'Where does the engine go?'

ummm , its a bit eager to go of if you run it at the sensitivity level 1 or 2 ,but on 3 it only goes off on low rpm high boost which is where i feel its a bit advanced , i havnt ever heard any knocking from my engine at any time so its mainly for higher boost which i havnet used yet .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

I could never hear any knock,but close examination of the piston lands suggests det in all cylinders.

'Where does the engine go?'

yes steve thats what i thought ,the amount of engines that have gone bang with no warning seems to suggest the a series has the capacity for silent termination !

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Hi,
You're right it does vary on bore size, I've not set mine up yet so I don't know the freq. However this might help...
Cheers,
Gavin :)

VEMs Authorised Installer / Re-seller. K head kits now available!

WB/EGT gauges. Click here for customers write-up

Visit www.doyouneedabrain.co.uk

My Mini build diary

Thanks Gav,that looks useful.I'm only trying to set up a warning system,rather than adaptive control,so can probably live with a degree less sensitivity.

'Where does the engine go?'

Thing is, its still no use if your enginee knocks and the knockbox doesnt tell you, thats what people are saying


You need it to be sensative to the right frequency at the right time, otherwise the information the ebox will tell you is useles for purpose.


As said, every engine is different, so you neeed to find a system that you can tune to tthe eright frequency.

If you look deep enough through the VEMS Wiki, you will find that there is a chap who used he VEMS only for wideband, knock and ignition, and that was on a Turbo A Series!

Yes I noticed some familiar names on there.So from this i conclude I need a tuneable system,but then I have to identify my blocks natural frequency.this could be as simple as hitting it with a hammer.So how do the RR guys detect knock,just from wideband analysis?

'Where does the engine go?'

Hi,
From what I've read on the wiki, there's 2 ways, one needs closed loop controlled injection and the other is to twat the block near the sensor with a big spanner or the like.
Cheers,
Gavin :)

VEMs Authorised Installer / Re-seller. K head kits now available!

WB/EGT gauges. Click here for customers write-up

Visit www.doyouneedabrain.co.uk

My Mini build diary

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

OK Steve I hear you!

'Where does the engine go?'

Some also say detonation can be detected on the graph trace on the dyno....others cant.

Whether its nonsense or not, Im not sure, or perhaps it depends which dyno.
Using your ears is the best way though. Although it takes a bit to get used to what you are listening for.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

I would've thought that whacking the block with something could cause bad calibration - sure, you'll get a burst of HF noise but it won't be the same as the standing wave you get in the chamber when it really knocks.

I reckon that hooking a knock sensor up to a good high-bandwidth digital oscilloscope (or failing that a decent PC soundcard with the correct amplification), making it knock a few times by advancing the timing, and then running spectral analysis on your data would give you good information about how to set your filter up. You could then play your recorded waveform back into your filter to see if it gets through cleanly.

DSPs are the best way but that's a level of development best suited to large manufacturers!

ttfn,
--
Olly

Edited by Funkster on 8th Jul, 2008.

Thanks Oliver,sounds like I need someone to make up a bespoke bit of electronic wizardry!

'Where does the engine go?'

;o)

Data gathering can be done with standard gear that's lying around us, but what matters is how adjustable the filters are on any piece of knock detecting hardware. If it's only a very basic filter, then a bespoke filter to replace or go in line would be the way to go.

Taraa!

Guys.

Just to add to the list of DIY knock detectors ............

I'm using KnockSense MS. I imported this from the US for about 60 USD and I have it connected into my Megasquirt ECU which is set up to retard ignition by an amount I set on detection of the first knock after a given RPM and MAP, which I set as well. The unit has all the filtering and amplifying built in. It's very easy to fit and just requires a Bosche sensor (or equiv) which I bought new in Uk for £20. The sensor is bolted to the front of the block using one of the two alternator bracket bolt holes between cyls 2 & 3. Certainly not ideal, but better than nothing at all.

There is a sensitivity screw but I haven't really set it up yet as I'm still on light loads running in. However, the thing is giving me a whacking great super bright LED output on the dash and a voltage output to the ECU which I can data log.

The unit was recommended by Phil Ringwood on the Megasquirt website: www.ExtraEFi.co.uk.

More details on KnockSense MS can be found at :

http://www.viatrack.ca/

Richard

Minivanless, but reluctantly happy living with the decision. There'll be another one day.
http://www.youtube.com/profile?user=minimadmotorman#p/u

Thanks,Richard,I'll be interested to hear how you get on with this when you wind the boost up.

'Where does the engine go?'

I'm running a Knocksense as well, he did mention the bore size when I told him what car I was going to put it on so that makes me suspect that it may be tuned for the boresize.

My problem is does it work?? Only way to find out is to make it knock I guess and I'm a bit reluctant!!


Currently I have it mounted on the alternator bracket bolt between cylinders 1-2, probably not ideal. Initially It was oversensitive but adding a 200k resistor to desense it seems to have calmed it down. I am a bit worried about drilling holes in the block so was thinking about having a nut welded on the block at a strategic position, whats the thoughts lads?? anyone have any views on strategic positions??

terry

website:- http://www.terryhunt.co.uk