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Knock Sensor

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Quoll Officially Full-On Dubber

232 posts · joined Jan 2003 ·

#722251
Does anyone know a good place to put a knock sensor on a type 1 engine, as I am planning on using jaycars electronic ignition thing with the knock sensor module?

cheers

Camo Custom Title Time!

1,936 posts · joined Oct 2007 ·

#981658
It's been 4.5 years since the above question, anyone come up with any good suggestions yet.

Not sure if it should be on the case, barrels or heads 🤪

Cheers, Kev
I thought rebuilding a VW would be cheap - Shit I was wrong, just don't let the wife know !!!!

Click here for my (slowy) modded 1961 Beetle build.

bugzla Custom Title Time!

1,164 posts · joined Jun 2007 ·

#981668
that is interesting would love to know also

vlad01 Compulsive Aussie Vee Dubber

4,270 posts · joined Jun 2010 ·

#981676
Best would be on the block nearest to the cylinder. heads probably pose too much valvetrain noise as could false trigger knock counts.

I am not sure on what type of sensor you will need as some are tuned to work in certain frequencies. I think the flat response type suits all engines?

If you are using an ECU to listen to the knock sensors and do the knock retard function you will need to have a knock filter board to suit the resonant frequency of the bore diameter.

We have some programmable knock boards here. Can be used as a stand alone unit I think with the LED output but its mainly designed to work with Delco ECUs. Should be able to be used with other ECUs too?

http://pcmhacking.net/forums/viewtopic.php?f=11&t=1820

product info here.

http://pcmhacking.net/forums/viewtopic.php?f=14&t=2993

71 notchback,
Past owner of, 70 NB, 73 SB and 72 FB TLE

Camo Custom Title Time!

1,936 posts · joined Oct 2007 ·

#981693
Hi vlad01,

thanks for the links. I am not a member of that site and was wondering if you have 'festy' details as he doesn't live that far from me and I would love to have a chat with him.

I have a Megasquirt 3x system that I will be running and has inputs for knock sensors. But I have also been looking at this (click here - Knocklink G4) and was thinking I could use this setup for tuning purposes and then as a visual backup if I got bad fuel etc - example only.

Or if 'festy' wants, I can send you my details and he can ring me. Thanks again for your help.

Kev
I thought rebuilding a VW would be cheap - Shit I was wrong, just don't let the wife know !!!!

Click here for my (slowy) modded 1961 Beetle build.

psimitar Son of Jim - Creator of Good

2,506 posts · joined Jan 2009 ·

#981694
On the Subaru EJ engines the sensor is located on the block on the rear right cylinder. Closer to the crank centre than the head from memory.
madness is in the eye of the beholder 👍

vlad01 Compulsive Aussie Vee Dubber

4,270 posts · joined Jun 2010 ·

#981867
ideally it should be mounted in the cylinder water jacket as water transmits sound awesomely.

Unfortunately the AC engine doesn't have that luxury of water and the cylinders would be too hot for the sensors to last imo. The case nearest to the cylinders would be best.

71 notchback,
Past owner of, 70 NB, 73 SB and 72 FB TLE

1303Steve Scirocco Rare

8,650 posts · joined Aug 2002 ·

#981895
hi

I think it would be hard for a sensor detect a knock over other noise on an air cooled engine.

Steve

vlad01 Compulsive Aussie Vee Dubber

4,270 posts · joined Jun 2010 ·

#981916
nah, should be fine. Knock is a narrow band frequency. the knock filter is a band pass filter only letting in and processing the frequency of the knock then outputting as a digital signal.

That frequency being the the resonance of the bore diameter. So even if you have tones of noise the knock is detected as the rest of the noise it generally filtered out. That said though, the SNR is improved the less other noise there is, reducing the chance of false trigger.

That knock board I linked to is fully configurable via PC gui and can be adjusted as the engine is running to get the best knock detection.

71 notchback,
Past owner of, 70 NB, 73 SB and 72 FB TLE