Hello,

I would like to know, how exactly the knock control works on my Audi 200 20V.

What exactly the ECU does, if it recognises the knock event?

Does it everytime set IGA about -3 degrees and than slowly back?

And what the boost does? Is it also everytime somehow controled and reduced?

Thanx!
Karel5000

Piston ring land will break when you run at the knock limit.
Soft knocking the knock detection will not recognize.

Maybe 2° aren't enought - because knock control only detects strong knocking.
I know a lot of tuned turbo engines where the ring land is broken after 10-20k km.
From my experience with a knock box you have a "wide" range of "slight" knocking before it really knocks very loud.
I tested this with 95 Octane fuel, high CR in summer.
I will repeat it this summer with 102 Octane - I guess there is different behavior in the range of "slight" knocking.
Slight means, you can hear it with extra equipment but "standard" knock detections from the ECM won't detects it.

Here's a third gear pull from a 400+ hp car with my logger.
You can see knock, you can see ECU reacting, and you can see that requested timing does not change...

I use stock pistons in most cases. The stock pistons on AAN/ABY/ADU/3B are very strong and capable of 700hp. The only issues is the compression ratio.
We are talking about M2.3 here and the 2.2T engine. None of what you said holds any water in case on these engines or with this engine management.

It's perfectly safe to run M2.3 with some knock events occurring. Nothing will break, because the ECU sees knock perfectly unless you do exotic things

On V8 it's not adjustable, and it's crap. It doesn't have per-cylinder control...

On 2.2T everything is adjustable, as there is a different MCU and software for knock control.
And it's much better.

Yeah, from the V8 I only have experience with 3.6
I don't know about 4.2 but on 3.6 it was really crap at detecting knock.

Interresting. Thanx for your tips. I am very glad to hear from you.

I suspected the VAG COM, that it shows the ignition setpoint without the additional ignition nocking value only, because i set the ignition about 4° sooner and nothing. Without the Motronic 2.3 specifications it is not easy to do something...

Thats the reason, why i also build such an audio knock detection system - my older knock sensor as a microphone, my laptop and FFT. To hear nocking without a measurement, it is not so reliabe. At least for me. I have not tested the system yet.

I am very surprised, that such an old knock management system is so sophysticated. Can you tune the knock pre-windows, knock windows, frequencies (for each cylinder separetely), gain...?

I can not believe, that it is so reliable, anyway. There is still development of the knock management strategies in the car industry but there are still some problems with it. The nocking is practically detected throw statistics while sometims the knocking appeares but the knock control does not recognises it because of noise and on the contrary...

Yes, as the knocking depends very strong on the combustion area, specially on the materials, sizes or timing of components (knock frequency), and very much on the load (knock windows), it is very important to adjust these maps during tuning of engins. This is probably the reason, why engines blow after tuning not recognising knocking...

I would like to know, if the known tuning companies also adjust the knock maps during tuning...