Thread: Ask a tuner...
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Old 12-11-2012, 02:07 PM   #654
P3Auto
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2014 P3 Import Auto
AWD Dyno, Mods, etc

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Knock table voltages need to be set based on how much noise the motor makes when its not knocking. Remember you are dealing basically with a microphone on the block listening for the knock. As you increase RPM the noise levels go up that is why the voltage goes up.

The numbers you set sound ok but what really has to happen is you need to graph the knock voltage during a pull with your timing set nice and low so you can be "almost" positive you have no knock. One thing to note, too little timing can lead to a different kind of knock like effect. Then review the graph for any spikes. Base your knock voltages off the average noise floor of the pull. Then as you increase timing and start to knock you will see clear spikes. The idea is to have your voltage thresholds set low enough to catch real knock but high enough to ignore noise.

Here is an example pic from another thread about this..See the little spikes, thats usually what knock will look like above the avg noise floor.





Quote:
Originally Posted by 05_wRex View Post
Thanks Seth. I am using a v1 aem ems. I have the stock ecu with access port that came with it, but I've gotten used to the aem now. Lol. Plus the guy told me they had issues with the stock ecu. I didn't really understand why since he didn't explain when I asked what issues, but oh well. Lol. I also asked for the power map they had for the car and got nothing, so I'm essentially doing it on my own now. Good thing I am competent. There's just not a lot of specific info on certain things like timing. The only thing I see are superficial numbers like "that guys running a billion degrees of advance, no wonder his engine blew."

That is total total timing advance. As far as I can tell. Previous logs show those numbers for total timing. The knock cal was set to pull 4.9* at 0.04 volts at redline. 4 thousandths. Not tenths of a volt. I see a recurring 0.39 volts around 5500 or so. I have some aem log files I can send over. I only have one internal log and its outdated now. lol. I set my current knock cal table with the following procedure. I set the boost to the waste gate spring and noted the knock sensor voltage. Then set the knock cal table just above those values and it hasn't pulled timing since. knock cal table is currently set to 0.19 volts at 2500 rpm up to 0.68 volts at 8000 rpm. What are your thoughts on the original knock table? And my current one?

Thanks,
Sean
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