Knock sensor position.
Turbo Mini Forums

For those of you that have experimented with these, which, if any position did you find worked best or at all ?

Cheers
Phil.

WWW.TURBO-MINI.COM

short bolt of the engine steady on the head for me Phil

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

Mines in the same position as Roberts. The ecu is compatible but I’ve Never got around use it tho 😳

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

Thanks chaps.

Phil.

WWW.TURBO-MINI.COM

Engine running but not yet tested.


In theory same distance from chamber to sensor for all 4 cylinders and away from valve gear should give decent results.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

I've seen the knock data from mine and the signal is very noisy when you get the engine going. Not had a chance to look at it in detail yet, but will have to do so to be able to set up Knock sensing propperly. My sensor is mounted on the very top screw for the coil mounting bracket on the MPi block.

I’ve seen Swiftune use a 70mm long brass pipe, squashed flat on one side...then drilled and screwed to the upper alternator bracket thread in the block. Over the other -still round- side of the pipe a length of fuel hose is fitted...put the other end in your ear and hey presto, you can now listen to knock!

Why write the above? Well a) the alternator bracket seems a good enough location for the human ear to effectively listen to knock, so it MIGHT be a good spot for a knock computer far less advanced than the human brain. B) whilst installing a knock sensor at whichever spot and dailing it in, you can run a parallel check with the human ear.

Please be advised that knock sensors only work up to about 5500rpm, so for higher rpm listening to knock yourself (at least on the dyno, not when shopping for groceries) is a good idea.

Final question: would a steel/alloy bung to replace the center core plug with be a nice central spot to mount a knock sensor without having to drill/machine the engine? If you guys think it will work where can I claim my design rights ?

On any vehicle I have ever seen with knock sensors they are aprx half way up the cylinder bore, on the block. that makes the upper alt braket bolt location almost perfect. my only concern there would be potential noise from the alternator itself. I have never experimented on an a-series with knock placement, but seems a good place to start for me.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

Link to a picture on facebook of the swiftune analog setup:

https://www.facebook.com/swiftuneengineerin...?type=3&theater

When I have had my car on the rolling road. We have always fitted it to the alternator bracket.

Just came to mind, my 16V Lancia Integrale Evo had its OE knock sensor fitted on the cylinder head close to the head gasket so your solution might just work perfectly.

On 5th Feb, 2018 Paul S said:
Engine running but not yet tested.


In theory same distance from chamber to sensor for all 4 cylinders and away from valve gear should give decent results.

Edited by Evoderby on 8th Feb, 2018.

I'm a bit puzzled by the comments that the best location is on the block. I know very little about knock but it is well documented that it usually ocurrs between TDC and 10 Degrees ATDC which means that the block is hardly exposed to the pressure pulse whereas the head gets a hammering.

Time will tell. I'll have a look and see if Tuner Studio can tell me anything next time I run it.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Most of the oe sensors I have seen are on the block. My thinking was that the noise gets transmitted down the rod into the crank and into the block by the mains, hence the sensor is listening for it there. But happy to be told otherwise.

And just to throw my tuppence in, (seing as we are lol) knock frequency is a function of the bore. That is to say knock is the "ringing" of the bore. so knock will always be picke dup most accurately on the block, on an area coupled mechinically with the bore close to where the event occurs.

EDIT I have never ever seen an OE knock sensor on a cylinder head. but in one occasion due to lazyness I added a resonant (non bosch type) knock sensor to the head of a MZ toyota engine (I later removed the inlet and did it properl)y and it did "work" i.e. the ecu flagged no codes. but im not sure id rely on it.

Edited by evolotion on 9th Feb, 2018.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

a soupcon of input ,

in the spud , on two occasions have i had the knock light on . once was at avon , good launch ,and mid track light was flashing then on fully , i tried to back off to make it go off while still on boost , but i failed , it as the one and only time it blew a head gasket , and interestingly matt woods also blew his head gasket ...we assumed back fuel from the local stn .


next was following a subaru impretsa,, i was holding 6500 rpm in top 3.1:1 dff on 165.6012 tyres , for a fair period of time say up to a minute ...and it just started flickering ..this was on 6 psi boost .i assumed i had a touch to much timing for the heat build up in the chamber .



this is a turbo xs knock-lite .

Regards
robert.

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

Interesting paper on the subject here:

https://dspace.lboro.ac.uk/2134/9175

Explains a lot about how the knock sensor works and how the block resonates due to knock.

The sensor is best located where the block is likely to vibrate the most. Very complex to determine empirically, so trial and error really.

On their particular test engine they recommended placing the sensor on the block just below the head face.

I wish I had done more research a few years ago

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."