Knock help

[Caric]

What are the best ways we have to monitor knock in our cars?

[ojcool]

You would have to datalog the Knock sensor with something. If someone has a scantool and the right cartridge for the sRT I would think the scantool could give you some data from the knock sensor.

[Caric]

Quote: Originally Posted by ojcool

You would have to datalog the Knock sensor with something. If someone has a scantool and the right cartridge for the sRT I would think the scantool could give you some data from the knock sensor.

I do have a scan tool and I can see timing in real time. The thing is that while most claim timing being pulled even at like 22psi I noticed that my timing was rather strong and steady. Almost the same as stock. I was going to just do the old school thing and just keeping going up bit by bit untill I saw timing being pulled and than back off a bit. I figured that having something that read knock would allow me to do it a bit easier.

[dsmlights]

Quote: Originally Posted by Caric

I do have a scan tool and I can see timing in real time. The thing is that while most claim timing being pulled even at like 22psi I noticed that my timing was rather strong and steady. Almost the same as stock. I was going to just do the old school thing and just keeping going up bit by bit untill I saw timing being pulled and than back off a bit. I figured that having something that read knock would allow me to do it a bit easier.

rage teck sells knock meters

[never2muchboost]

you can buy guages but the more accurate way unfortunately is much more expensive.i did some research on mine and ran a twisted pair down to the knock sensor then hooked up a scope in the car

[ojcool]

Quote: Originally Posted by never2muchboost

you can buy guages but the more accurate way unfortunately is much more expensive.i did some research on mine and ran a twisted pair down to the knock sensor then hooked up a scope in the car

Necessity is the mother of invention....

[OrAnGe-SrT4]

HKS sells a A/F-knock monitor device..pretty kool

[Caric]

Quote: Originally Posted by never2muchboost

you can buy guages but the more accurate way unfortunately is much more expensive.i did some research on mine and ran a twisted pair down to the knock sensor then hooked up a scope in the car

how did it work out for you?
how did the knock you saw messure up aganist timing being pulled?

[Caric]

and thank you to all those that have pointed us in the right directin of where to look for knock sensors

[never2muchboost]

Quote: Originally Posted by Caric

how did it work out for you?
how did the knock you saw messure up aganist timing being pulled?

i saw tons and tons of noise,there was a almost constant .5v positive spike which would make sense why the safc knock feature doesnt work but i did notice just above a +1v it would start to pull timing.the negative side of the scope looked like a fish finder

[supernavagator]

Quote: Originally Posted by OrAnGe-SrT4

HKS sells a A/F-knock monitor device..pretty kool

does this work/fit on our cars

[WhatsADSM]

Quote: Originally Posted by never2muchboost

i saw tons and tons of noise,there was a almost constant .5v positive spike which would make sense why the safc knock feature doesnt work but i did notice just above a +1v it would start to pull timing.the negative side of the scope looked like a fish finder

You do know that you have perform frequency based analysis to get a really good idea of what is knocking and what is just engine noise... right? Remember the knock sensor is a microphone (AC) not just a basic voltmeter (DC).

So unless you can perform DFT - in your head on the fly, while driving - having it on a scope may not help very much. Besides if all you wanted was a voltage, just hook up to the knock sensor with a standard multimeter (analog display would help you see the quick spikes).

If you really want a way to get the BEST knock reading, get a DRBIII... That way it is literally the PCM telling you when it sees knock.

Murray

[turbojack]

Murry, that DFT link......WAY, WAY beyond me. I'm not gonna get a headache trying to make sense of that. Help me a little to understand more without making me read that.

From what I gather/guess, the software in the PCM has been programmed to read the knock signal, clean it up (ignore back round noise), and then advance this cleaned info further along in the code for the PCM to process and then take action if necessary = pull timing. No way we can do this without big time $$$$ tools/equipment.

What about a simple device that taps into the knock sensor signal and logs knock events as well as timing? Even though it's not perfect it should serve as enough info to help a little, no?

http://www.viatrack.ca/
"There is also a separate pseudo analog channel that allows capturing the knock event with a data logger"
After reading a little about this and thinking, this could mimic what the code in the PCM does in cleaning up the knock signal...and pretty inexpensively.

When analyzing, the knock event logs from this they would need to be overlayed onto timing logs, find timing being pulled, then look at what shows for the knock event. This setup would not be 100% but enough to get a basic idea of what conditions and when knock starts ocurring.

After a fair amount of logging and analyzing you might be able to tweak the knocksense unit so that you can have it send a signal (to a LED for example) just before you would expect the PCM to pull timing....set the knocksense to be a little more sensitive then factory.

" The internal threshold pot can be set so that it triggers on the desired level of the knock signal".

Using the led from the knocksense, a decient wideband, EGT readings, and boost you might be able to road tune a little better, no?

Anyway, if you have some time, explain a little more about DFT withou me having to read what you linked

[never2muchboost]

Quote: Originally Posted by WhatsADSM

You do know that you have perform frequency based analysis to get a really good idea of what is knocking and what is just engine noise... right? Remember the knock sensor is a microphone (AC) not just a basic voltmeter (DC).

So unless you can perform DFT - in your head on the fly, while driving - having it on a scope may not help very much. Besides if all you wanted was a voltage, just hook up to the knock sensor with a standard multimeter (analog display would help you see the quick spikes).

If you really want a way to get the BEST knock reading, get a DRBIII... That way it is literally the PCM telling you when it sees knock.

Murray

a dvom isnt quick enough to see it, you would have to look at it on at least a 5ms scale.i actually have a drb and have logged it but i wanted to see exactly what it was doing in real time.anyone who can figure dft on the fly or at least says they can is full of shit but the scope gives you a good idea of how much noise the pcm is filtering out.i get ur point though

[05SilverStreak]

I think the Pythagorean theorum would be faster and easier but not while driving. But in all actuallity the inconsistency of the algorythms of any of your theorums in that link would make it impossible to perform in your head while driving, so the idea that any of this is actually related the original question is ambivolent. Here we go with the smart guy shit again.