[scalbert]

There have been some questions on how to determine if one is knocking and the only way to know for sure is to log the actual ignition timing. Currently there are two ways to get the data as required; the BT tool or PROcede Rev II. OBDII interfaces can get ignition timing but is often too slow, not enough data points collected, to provide valuable data. You need at least 10 points per second to be able to see a real curve and events.

The idea is to log the Ignition Timing and RPM at a minimum. Other values can be logged but are not representative of knock occurrences. If knock occurs, only timing is adjusted by the DME, boost is not. It is only after significant knock, to where the DME has reached its limit on pulling timing, that boost will be affected by way of a code and limp occurrence.

Knock has multiple causes which all have a relation. In our case, too much boost/compression for a given A/F ratio and ignition timing are the most typical causes. Lower IAT will lessen the issue but eventually too much boost and not enough fuel will eventually run into knock.

For an example of a typical curve, see below. As a preface, there is a mechanical reason why an ignition curve looks the way it does. During cruise and light load, the engine will be running significant advance. On the onset of high load/large throttle openings, the ECU will pull timing. But as engine speed increases, timing will be added back in order to keep the actual firing and burning events the same. As the engine speeds up, the time to fire and burn decrease so that more advance is needed.

Stock Curve, blue line:



Notice the nice bowl shaped curve and the continual upward climbing of advance as engine speed increases. This is normal and what is expected.

Now for comparison, here is a new log which shows a sudden drop at 5200 RPM. The ignition timing dropped approximately four degrees at about 5200 RPM. This was due to a knock event and the DME responding accordingly.



Here is another example but with two events recorded at 4500 and 5200 RPM.



In both it appears obvious that timing was pulled as a reaction to something and that something would be knock.

One of the reasons for this thread was a discussion on whether or not knock events occurred in a recent H20/Meth kit thread. Let me add that this is not meant to take away anything from that excellent write up and the OP of that thread deserves commending for talking the time to install, write up and share with everyone. But in looking at the logs, I saw something striking; knock events when stated there was none. I disagreed; hopefully respectfully.



Please keep in mind the Y scales are not the same so the events are no as prevelant.

At 2300 RPM there was 5 degrees pulled, at 3200 RPM there was about 3 degrees pulled and at 5700 RPM there was another event which about 3 degrees was pulled. Does this mean the kit was not doing its job, absolutely not. If anything, it was doing a great job. Seeing as though this was Map 9 which is a race gas map only and the seeming severity was minimal, only about 3 degrees pulled at times, it did what it was supposed to.

But hopefully this thread provides some insight as to how to read the timing logs. And as always, discussions are welcome but please keep it respectful is you do not agree with others.

[Clap135]

I disagree with knock at 2300 rpms. Looks like ignition was retarted to spool the turbos. Many turbo cars do this. The other two events I agree with.

Now that I look at it more, that also might be the point where the OP has the meth to "kick on". He might be using to big of a nozzle. There are many members who think bigger is better, which is not the case. Too much meth/alky will actually cause the engine to knock. If its not a progressive set it up, it might be too much spray downlow.

[scalbert]

Originally Posted by Clap135

I disagree with knock at 2300 rpms. Looks like ignition was retarted to spool the turbos. Many turbo cars do this. The other two events I agree with.

Now that I look at it more, that also might be the point where the OP has the meth to "kick on". He might be using to big of a nozzle. There are many members who think bigger is better, which is not the case. Too much meth/alky will actually cause the engine to knock. If its not a progressive set it up, it might be too much spray downlow.

It is hard to say as that area is unusual. Even though the IAT starts climbing, which suggests boost rise, the timing bottoms out which is not something I have not seen in any timing logs. It then jumps up to about 11 degrees and then drops to about 6 degrees. The rest is somewhat typical of many curves.

What I do like is that it finished at nearly 12 degree advance, which is decent on this engine while running a race gas map. That was similar to the Map 6 test I did in the above chart while on 93 octane.

[usc335]

Isn't the timing drop at ~4500 rpm pretty standard on tuned cars? If so, is it due to knock events, vanos timing changes, or something else?

The logs I've posted before all consistently drop at ~4500 rpm and the timing curves for 5 runs were right on top of each other from 4500 rpm to redline.

[Former_Boosted_IS]

Originally Posted by Clap135

I disagree with knock at 2300 rpms. Looks like ignition was retarted to spool the turbos. Many turbo cars do this. The other two events I agree with.

Now that I look at it more, that also might be the point where the OP has the meth to "kick on". He might be using to big of a nozzle. There are many members who think bigger is better, which is not the case. Too much meth/alky will actually cause the engine to knock. If its not a progressive set it up, it might be too much spray downlow.

You can argue with him all day and get no where. Clap you are 100% correct and every tuner I showed my logs to said the exact same thing... the timing drop is common to help spool the turbos. What is amazing to me is that Scalbert doesn't realize this. Clap, also please look at the log below as it was the 3rd run ever on this map with the Snow Performance kit. The second timing drop (on the graph Scalbert posted) appears to be adaption occurring.

For those that do care, there are different interpretations on what is knock and what is not. Second, all knock is not the same and it can be insignificant to severe, hence the reason the superknock code wasn't triggered nor was a knock flag indicated. Please do not take this post as gospel. In the very next run (after the log posted by Scalbert), the following log was recorded and is smooth as butter:



The second timing drop in the first graph appears to me and many trusted tuners as nothing other than the DME adapting. In fact, I did the same log on a stock car after a reset of the adaption values and guess what it looked like? Exactly the same. I hope the forum understands this is the way the car adapts. If indeed the small timing drops were dangerous, then why are similar insignificant timing drops noted when the car adapts stock? Clearly in the second log I just posted (conviently not posted), you see a rock solid timing curve.

I will not participate in this thread anymore, nor will I continue discussions that are full of smoke and deception. My hope is only that the community realizes that what Scalbert says is not shared by all professionals in this or other communities.

[alextremo]

I have 3 questions about this (forgetting the event @2300 RPM) Not to discredit the meth write up (which was a great DIY BTW) but because I used the assumption that these were knock events when fine tuning my Procede and I want to understand better what I'm looking at.

1) If this is adaptation by the ECU, would you expect to see these events again after driving the car for a few days under normal driving conditions? In other words, isn't the adaptation continuous and the car would therefore adapt to not being at ~16psi and not having meth after a few days of normal driving (no WOT) and then have to re-adapt when you floor the pedal on the right? If so it would imply that these events are an expected occurence every time you change driving behavior.

2) If this is adaptation via "riding the knock sensor", is that a bad thing? Does this only occur after knock happens, or does the ECU have the ability to pull timing based on the likelihood that a knock event is imminent and therefore have no adverse effect on the engine?

3) If this is not knock, what would knock look like with the parameters that were logged?

[Former_Boosted_IS]

Originally Posted by alextremo

I have 3 questions about this (forgetting the event @2300 RPM) Not to discredit the meth write up (which was a great DIY BTW) but because I used the assumption that these were knock events when fine tuning my Procede and I want to understand better what I'm looking at.

So you understand what I am saying. Not everyone says that every timing drop always equates to a knock. If indeed it did, then every single car on here is knocking every time you floor the car.

[scalbert]

Originally Posted by usc335

Isn't the timing drop at ~4500 rpm pretty standard on tuned cars? If so, is it due to knock events, vanos timing changes, or something else?

The logs I've posted before all consistently drop at ~4500 rpm and the timing curves for 5 runs were right on top of each other from 4500 rpm to redline.

There may be an occurance at 4500 which causes a dip in timing which may still be knock induced. However, no stock logs I have done or seen have this occurance. So while it may be a vanos event, that change in cam timing may cause a knock event as well with the increased load.

Nevertheless, the logs I posted clearly show knock events outside of the 4500 RPM range.

[scalbert]

Originally Posted by alextremo

1) If this is adaptation by the ECU, would you expect to see these events again after driving the car for a few days under normal driving conditions? In other words, isn't the adaptation continuous and the car would therefore adapt to not being at ~16psi and not having meth after a few days of normal driving (no WOT) and then have to re-adapt when you floor the pedal on the right? If so it would imply that these events are an expected occurence every time you change driving behavior.

2) If this is adaptation via "riding the knock sensor", is that a bad thing? Does this only occur after knock happens, or does the ECU have the ability to pull timing based on the likelihood that a knock event is imminent and therefore have no adverse effect on the engine?

3) If this is not knock, what would knock look like with the parameters that were logged?

1) Yes, you would. Just like reseting knock adaptation or running a lower boost maps and switching. The question is if the DME is reacting quick enough so as not to worry about it. We cannot say 100% either way at this point in time.

2) Refer to 1.

3) The high load instances are a reaction to knock regardless what some want to beleive.

[scalbert]

Originally Posted by Former_Boosted_IS

You can argue with him all day and get no where. Clap you are 100% correct and every tuner I showed my logs to said the exact same thing... the timing drop is common to help spool the turbos. What is amazing to me is that Scalbert doesn't realize this. Clap, also please look at the log below as it was the 3rd run ever on this map with the Snow Performance kit. The second timing drop (on the graph Scalbert posted) appears to be adaption occurring.

For those that do care, there are different interpretations on what is knock and what is not. Second, all knock is not the same and it can be insignificant to severe, hence the reason the superknock code wasn't triggered nor was a knock flag indicated. Please do not take this post as gospel. In the very next run (after the log posted by Scalbert), the following log was recorded and is smooth as butter:



The second timing drop in the first graph appears to me and many trusted tuners as nothing other than the DME adapting. In fact, I did the same log on a stock car after a reset of the adaption values and guess what it looked like? Exactly the same. I hope the forum understands this is the way the car adapts. If indeed the small timing drops were dangerous, then why are similar insignificant timing drops noted when the car adapts stock? Clearly in the second log I just posted (conviently not posted), you see a rock solid timing curve.

I will not participate in this thread anymore, nor will I continue discussions that are full of smoke and deception. My hope is only that the community realizes that what Scalbert says is not shared by all professionals in this or other communities.

Smoke and mirrors? What would I be attempting to disguise? Who are these said tuners? If anything, it appears you have an agenda. I have no skin in this game other than an attempt at having a rational discussion which seems to be one sided.

An attempt to spool the turbos by retarding timing? Granted, yes, the EGT's will go up but there are better ways to get the turbo's moving.

But discounting the roll on event (even though timing dropped and started climbing again so the turbos were already up to speed), there were other events recorded. And I agree, the new log looks better albeit the time resolution is low. But the original one I posted from your thread showed events up higher. You say it is adaptation, but to what? Since this is ignition timing we are dealing with that adaptation would be to knock events even if they are minor.

[Former_Boosted_IS]

Originally Posted by scalbert

Smoke and mirrors? What would I be attempting to disguise? Who are these said tuners? If anything, it appears you have an agenda. I have no skin in this game other than an attempt at having a rational discussion which seems to be one sided.

An attempt to spool the turbos by retarding timing? Granted, yes, the EGT's will go up but there are better ways to get the turbo's moving.

But discounting the roll on event (even though timing dropped and started climbing again so the turbos were already up to speed), there were other events recorded. And I agree, the new log looks better albeit the time resolution is low. But the original one I posted from your thread showed events up higher. You say it is adaptation, but to what? Since this is ignition timing we are dealing with that adaptation would be to knock events even if they are minor.

I promised to stay out of the thread, but you do appear to be leaving this civil. If it stays this way, then this thread does have some merit. As long as we agree there are differences between minor KR events that are common and severe knock events, then I am fine. What people need to know is these minor KR events are actually quite common on the car during the adaptation process. Knock as most traditionally use it and understand as damaging are a whole different animal.

[scalbert]

Originally Posted by Former_Boosted_IS

I promised to stay out of the thread, but you do appear to be leaving this civil. If it stays this way, then this thread does have some merit. As long as we agree there are differences between minor KR events that are common and severe knock events, then I am fine. What people need to know is these minor KR events are actually quite common on the car during the adaptation process. Knock as most traditionally use it and understand as damaging are a whole different animal.

I agree, there are knock events with all tunes and are typically minor. I have stated as such many times in the past and have shown and discussed this in many logs.

This DME does an excellent job of reacting to knock and adding back in timing quickly. But it does occur which was merely my point. Although I have a very difficult time getting it to occur on a stock tune. But I do run 93 octane only...

[Ridge335i]

Let me guess; PROcedes "timing" control would prevent all of this.

[scalbert]

Originally Posted by Ridge335i

Let me guess; PROcedes "timing" control would prevent all of this.

Nope, does not prevent it. The idea is to minimize the frequency and intensity. But that is a discussion for another thread.

[Ridge335i]

Originally Posted by scalbert

Nope, does not prevent it. The idea is to minimize the frequency and intensity. But that is a discussion for another thread.

You know I was just giving you a hard time anyways, Steve.

[scalbert]

Originally Posted by Ridge335i

You know I was just giving you a hard time anyways, Steve.

Ya, I slowly picked that up.

[usc335]

Originally Posted by Former_Boosted_IS

I promised to stay out of the thread, but you do appear to be leaving this civil. If it stays this way, then this thread does have some merit. As long as we agree there are differences between minor KR events that are common and severe knock events, then I am fine. What people need to know is these minor KR events are actually quite common on the car during the adaptation process. Knock as most traditionally use it and understand as damaging are a whole different animal.

Scalbert is always civil and I think he's one of the most respected guys on the forum!

[jpsimon]

Originally Posted by usc335

Scalbert is always civil and I think he's one of the most respected guys on the forum!

+Infinity

I don't think I've ever seen him NOT civil.

[alextremo]

Originally Posted by scalbert

1) Yes, you would. Just like reseting knock adaptation or running a lower boost maps and switching. The question is if the DME is reacting quick enough so as not to worry about it. We cannot say 100% either way at this point in time.

2) Refer to 1.

3) The high load instances are a reaction to knock regardless what some want to beleive.

Thanks - I now have a couple more questions

a) Is the only way to know 100% if these events have a tangible negative impact on the engine to look at the internals after this has been occuring for a some period of time?

b) Assuming that they do have negative impact (me being risk averse) Are there other variables that we can log that might shed some additional light (engine load, boost target, boost, etc)?

c) Are there degrees of severity of these events that can be ascertained based on readings of these variables? For example, can we classify by [Severe, High, Medium, Low] where [x] number of these events with timing pulled more than [y] degrees are seen over [a] consecutive runs with greater than [b] % load on the engine? What would the accepted variables and values be for a N54 engine?

Seems like c) probably has a subjective answer(s), and not sure it could happen, but I think it would be nice to have some kind of consensus and standard way to measure this based on data. Would be the safety complement to the FATS performance measurement.

[scalbert]

Originally Posted by alextremo

Thanks - I now have a couple more questions

a) Is the only way to know 100% if these events have a tangible negative impact on the engine to look at the internals after this has been occuring for a some period of time?

b) Assuming that they do have negative impact (me being risk averse) Are there other variables that we can log that might shed some additional light (engine load, boost target, boost, etc)?

c) Are there degrees of severity of these events that can be ascertained based on readings of these variables? For example, can we classify by [Severe, High, Medium, Low] where [x] number of these events with timing pulled more than [y] degrees are seen over [a] consecutive runs with greater than [b] % load on the engine? What would the accepted variables and values be for a N54 engine?

Seems like c) probably has a subjective answer(s), and not sure it could happen, but I think it would be nice to have some kind of consensus and standard way to measure this based on data. Would be the safety complement to the FATS performance measurement.

A) If these events are as minimal as they seem, you are correct in the analysis. Plugs are also a good indicator and from what it seems, none have shown serious knock occurring. But it is something to keep an eye on. Maybe a compression test down the road. But the fact is that we haven't seen any telling signs as of yet and it would probably begin with damaged plugs.

B) Ignition timing is the most telling in seeing how the DME is responding to ignition events.

C) There is no distinct value we can read that shows the intensity. We can somewhat derive it by looking at how much timing is pulled when an event occurs. If I were to guess, 2 - 3 degrees is minor, 5 - 6 degrees would be moderate knock. Anymore and you will throw a code. This "Super Knock" code is due to hitting the limits on how much timing the DME will pull. At that point it will limp.

Another method would be to look at discrete points in the RPM band and see what the overall timing is on different pulls.

[alextremo]

Thanks again. I've got a bunch of data from when I was setting the user adjustables on the Procede a couple weeks back. I'll go back and see if I notice any trends on where the events were occuring and how big the drops were.