How should I read the values I get from the knock sensing? my knock sensors are on both sides of v6 engine and the sensor 1 is closest to cylinder 2. sensor 2 is closest to cylinder 5. So I assume the Cyl 5 and 2 show higher values than other cylinders.
I used these sensor paramerter values from my V2 setup and tried to take on pull with 5 base ignition timing. and cyl 5 has the highest voltage. So the question is when is it really considered knocking? and what kind of voltage readings should the sensors show when engine is not knocking and when it is knocking?
How big spikes are considered as knocking? should I somehow change the loggin speed faster than 25hz or is that possible?
The channels show peak voltage betwen two samples so you do not loose any information about knocking even with 25Hz logging.
to make sure you should generate the know on medium load (safe for the engine) and check how the voltage from knock sensor reacts.
also use per cylinder gain to get equal voltage from all cylinders.
What kind of voltage range should I look for for idle and for load when setting up gains?
My system now shows around 0,25v on idle and biggest spikes I get from full throttle pull thougth whole rpm range and ignition angle set to 5 degrees full table, I get around 1-2.3v.
if I put ignition higher even to 7 degrees the voltage goes over that limit with same kind of pull. So how will I know how much voltage is bad, and how much is okey?
Biggest knock spikes I get are around 4000-5000rpm when the boost goes up. Upper rpm I dont have issues with higher ignition around 23-25degrees. I am using re85 fuel.
and for last my current ignition map that goes from 7 to 20 but think it should go higher, but im afraid to put it up more because im not sure what is considered knocking. I have had 25 at top before and it was better fot egt.
this was from some older log file, there was this one higher spike with cyl5, and the gains were not adjusted that time. is that spike hight enough to be knock?
I think noone can and will give u a clear statement if this is knock or not, since it is very hard to find the settings to detect light knocking without expensive measurement tools and just the values of the sensor.
I would do the following:
Ur gains are quite low…if this is ur target boost i would increase the gains that u roughly land at 2-2,5V with ur 5deg map. The 5 deg look quite smooth and i would take that as a no knock safe engine state (but u could also play a bit more with less ignition at lower rpm and watch the changing of the signal). Then do a run and set the engine noice to max values u see (maybe add a little).
Everything which crosses this line then u can consider as knocking.
Then play a bit with ur ignition and watch the behaviour of the spikes. U will fast get a feeling for the stronger knock events.
The real magic is to detect the light events…but this is just a guessing with the sensor values only i think.
This is an interesting topic because I have done exactly the same with my car. Set safe timing then set the threshold a little above that and then add more timing and like you said you would expect everything above the threshold you set to be knock but with mine when I add the timing the voltage rises above the threshold but still stays smooth.
Yes thats what I have beeing trying to do and test out different things. But with 5 ignition angle the car feels powerless…
I also heard that it not possible to get the engine with 9.3 compression ratio to knock with re85, and it will stop igniting before knocking.
So thats why im interested in how big of a spike is the knock really compaired to the rest of the graph. But I am scared to put ignition much higher to test it out.
I consider the big spikes as knock. If i use better fuel or reduce timeing, they get less or disappear. I have no expirience with E85, just use normal gasoline with different octane.
I think it is necesarry to push it to the limit to see real knock. If u set a proper reaction when crossing the engine noice line, there is no risk for the engine. Single knock events don’t kill the engine…permanent knocking is the dangerous thing.
Compared to ur logs my engine looks close to death^^…and i have even worse looking logs. Engine has 400k total mileage and 70k emu black mileage in this setup.
So be brave …but yeah…also heard of engines which just don’t knock.
I sadly can’t do something with V3 cause i use eWG which is not supported yet
…but yeah…also heard of engines which just don’t knock.