Knock sensor

[Reinhoud]

Not sure if anyone started a topic before..

 

Anyone here who fiddled around with a knock sensor (air cooled engine)?

If yes, how did you do it? What are the possibilities?

 

Thanks

 

 

[Gixer1460]

Possibilities in what regard?

They are not the easiest of devices to use AND get reliable data. They have to be placed to actually 'hear' the knocking above all the other mechanical noise and then output that to a datalogger. Some kits use a flashing LED or headphones but then you are back to trying to avoid the 'noise clutter'.  I wanted to include one on a turbo install with Motec ECU but a Motec guy told me not to bother as you may get the data, but unless it can control dynamic timing adjustments on the fly it is pointless (not possible even on Motec at that time, still not now). Really, only of use in real lean burn engines trying to eak out fuel mileage with OEM ecu programming facilities to optimise dynamic ign. timing.

[Reinhoud]

Thanks.

 

Possibility as in light coming on when there is knock/detonation..

 

But it's not really possible? 

[Gixer1460]

2 hours ago, Reinhoud said:

Thanks.

Possibility as in light coming on when there is knock/detonation..

But it's not really possible? 

As above, yes a light or sound of the knock is possible but particularly with a mechanically noisy engine like a GS or GSX - defining what is and what isn't knock is really hard. And if it's really bad, yes you'll get the warning - by which time it's happened, nibbled pistons or valves and what can you do about it? With carbs and fixed ignition you either re-jet or change fuel octane and / or change ignition curve which may compromise elsewhere in rev range, hence why it needs to be dynamic and adjust microsecond to microsecond and to learn what the new boundaries are.