Hi

I've looked through the FAQ and did a bit of searching, but I can't find any information about whether the knock sensor can be used with the megasquirt V2.2? Info seems a bit scarce on knock sensing with the MS in general, so if it can't be driven with MS, what's everyone using?

Thanks

Ian

 

There's a special circuit you have to build in order to use a knock sensor. It's a fairly complicated circuit.

There's also quite a bit of info on it at www.msextra.com, going there and doing a search should turn up quite a bit of info.

I personally have never used it.

Ken

 

I installed the extra board and used it for a little while. Not much help if you ask me because you have to adjust it to work and you never know if it's correct. I wouldn't waste my time or money if i had my druthers.

 

The problem is that you have to let the engine knock on purpose before you know if it's working.

There was a guy on the msextra forum who's name I can't remember that would build a tuned circuit for you though, which makes knock sensing more useful.

Ken

 

Thanks guys. I bought a knocksense before I saw the last post, but I'll see how it goes. The exchange rate works quite nicely in my favour, so it was actually quite cheap
The little unit is very well made and nicely presented. Guess it remains to be seen how well it actually works.

 

The knocksense works great with either the bosch sensor or the stock miata sensor. No idea if you have a threaded spot on your block for the miata sensor though.

 

I suppose you could test/ set it up by using a small hammer to lightly tap on the housing near the sensor to simulate knock, and watch for retarded timing with a timing light. Not exactly a real-world scenario, but enough to test the circuit.

 

i found a knock sensor laying around the garage, probably from some Ford. we put it on the O-scope and gave it a few flicks with a finger. it is definitely picking up vibrations. i think we can set this up, but i have a few questions:
i am not experienced in this matter, is it pretty evident when the engine knocks?
the sensor is basically a microphone, but does one have to filter the signal to pick up the specific "knocking frequency"?
or does one just look for a very high amplitued spike?
does anyone know the specific "knock charecteristics" for a RE? (as far as the signal from the sensor goes)
also, i hear that one must disable the sensor at certain RPMs as to not get false readings, does this have to do with frequency as well?