Whats the difference between a knock and a ping?
05-08-2005, 06:11 PM
#1
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Whats the difference between a knock and a ping? I know what a knock is, when the gasoline dentonates before the spark plug fires (caused by lower octane for higher compression cars). My Monte always use to ping so I replaced the vacume advance and retimed the car. That would make me think that the sparks were fireing before they were suppose to. My question is, what's the difference between and engine knock and a ping. Also, what is the difference between an upper engine knock and a lower engine knock and what would cause this to happen in an engine (like examples of both)?
I know this isn't an LS1-LS6 specific question, but I've always been curious and never asked (It's always embarrasing to admitt you don't know something).
I know this isn't an LS1-LS6 specific question, but I've always been curious and never asked (It's always embarrasing to admitt you don't know something).
05-08-2005, 07:27 PM
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It's all the same terminology.
A knock sensor spans a frequency of 5000 Hz to 8000 Hz (depending on the
MFG).
In that range of frequencies, sounds tend to resemble 'pinging' noises like a
fork against a glass, or rice shaken in a glass jar.
To make the sound of knocking on a door with your fist, the frequencies would
be much lower (about 1000Hz and lower).
So... the knock sensor is listening for pings. It's all semantics.
A knock sensor spans a frequency of 5000 Hz to 8000 Hz (depending on the
MFG).
In that range of frequencies, sounds tend to resemble 'pinging' noises like a
fork against a glass, or rice shaken in a glass jar.
To make the sound of knocking on a door with your fist, the frequencies would
be much lower (about 1000Hz and lower).
So... the knock sensor is listening for pings. It's all semantics.
Yes...and they are all BAD! 
