What's a "normal" avg ign value? (JB4 logs)

[Mr. Tech]

Hi guys, I'm looking through my logs and noticed that my avg ign is all over the place. Sometimes it's 2, other times it's 22, and it'll swing anywhere in that range on any given day. Even within the same day, it'll range from 4 to 18 on the same tank of fuel, same map (Map 2, 93 octane most days). I'll see the same sporadic results on Map 1 as well, again, with 93 octane.

I should also clarify that the avg ign isn't varying this much in a single pull. It usually stays within 1 of whatever value it starts at in the log.

I found this snippet from the official, how to read JB4 logs thread, and it makes me think 22 is a bad thing since avg ign is timing retard. That said, the note references a range of only 0-6 which, obviously isn't the case with the Stinger. So perhaps BMS changed how this parameter is calculated?

 

[Revvdmedia]

Hi guys, I'm looking through my logs and noticed that my avg ign is all over the place. Sometimes it's 2, other times it's 22, and it'll swing anywhere in that range on any given day. Even within the same day, it'll range from 4 to 18 on the same tank of fuel, same map (Map 2, 93 octane most days). I'll see the same sporadic results on Map 1 as well, again, with 93 octane.

I should also clarify that the avg ign isn't varying this much in a single pull. It usually stays within 1 of whatever value it starts at in the log.

I found this snippet from the official, how to read JB4 logs thread, and it makes me think 22 is a bad thing since avg ign is timing retard. That said, the note references a range of only 0-6 which, obviously isn't the case with the Stinger. So perhaps BMS changed how this parameter is calculated?

View attachment 27784

I think the log reading thread you attached can't be used as a perfect reference for the Stinger since I have read it and found it was normal to see as low as 3 degreed ignition advance on the BMWs. The WMI logs I have viewed from others usually show ignition timing around 15, but up to 20 near redline. I would call the WMI runs probably "perfect" ignition advance if they are seeing zero knock. I typically see my runs starting at 10 advance, curving up to 13 to 15 near redline if a good run. I have also seen my ignition advance dip as low as 4, but consistent among all cylinders which Terry notes as "learned" timing and not the car actively scaling back timing for knock on that run, that would show as ignition retard on individual cylinders, not all.

So for timing, I think the Stinger is capable of about 15-20 average ignition advance under perfect conditions. I feel 10-15 is about the norm from other logs I review. Dipping below 5 probably indicates there is, or was knock that the ECU is adjusting for, but that is just from what I have learned so far.

Terry@BMS has noted there are other factors with ignition timing, some of which I might not be taking into full consideration (ambient, etc). I usually observe my own logs based on what fuel is in the tank and what the IAT says that day as the 2 biggest variables.

One thing to note is I'm not fully sure how the JB4 calculates average ignition. I usually pull my logs into Excel and run my own calculations. Remember that your averages will be a bit lower especially on IGN1 since the car dumps timing to zero on gear changes.

 

[Mr. Tech]

I think you're right about the log reading thread not being completely applicable to the Stinger. The ignition advance from 10-15 sounds spot on with what I'm seeing. My ignition advance curves look decent, from what I can tell. I have been checking the individual cylinders for those repeated 3 degree drops on a single cylinder that Terry warns about. I haven't seen that yet, and hope to never see that.

It's mostly the avg ign I'm concerned about since that's timing retard even though I first thought it was the average ignition advance for all cylinders haha. That said, the log reading thread makes it sound like that variable should only go to 6.. clearly that's not the case on the Stinger so I have no idea how to properly read that, or what's normal. It was helpful taking a look at your logs from the other thread, though, because you seem to have very similar avg ign values to what I have.

I'm hoping someone from BMS can shed some light on exactly how we should read avg ign on a Stinger log.

Side note. I find it very interesting that so many people just drop a tune on and run the car without ever paying attention to logs. Their gauge for whether or not it's working is "Did something break? Not yet? Then it must be totally fine." haha. I love having the tune, but I want to run it in a way that I can keep this car for about 100k miles without significantly impacting engine or transmission life. Hence why I won't be doing WMI, or any higher maps.

 

[Revvdmedia]

Side note. I find it very interesting that so many people just drop a tune on and run the car without ever paying attention to logs. Their gauge for whether or not it's working is "Did something break? Not yet? Then it must be totally fine." haha. I love having the tune, but I want to run it in a way that I can keep this car for about 100k miles without significantly impacting engine or transmission life. Hence why I won't be doing WMI, or any higher maps.

That is simply different strokes for different folks. Some people will have difficulty learning the mechanical nature of a vehicle or even the tuning aspect. Everyone has their own skill set, and for some, this is not theirs. There are also others that simply can't be bothered to worry about it, and it is their choice. I think at the minimum, as long as they're putting 91 octane in the tank, they're doing the minimum. I am blessed with the ability to mentally break down things and figure out how they work with simple drawings or explanations.

 

[Terry@BMS]

AvgIgn is not connected in the Stinger firmware, yet. When looking at timing look at cyl 1-6 timing values and specifically for cylinders diverging from the rest during higher boost higher load runs.

 

[Mr. Tech]

AvgIgn is not connected in the Stinger firmware, yet. When looking at timing look at cyl 1-6 timing values and specifically for cylinders diverging from the rest during higher boost higher load runs.

Oh, interesting. So what is AvgIgn logging then? From engineering, I know that cells can't populate unless they pull data from somewhere, or calculate it based on other cells. Otherwise, a null character is used as a place holder.

Is it just running calculations without all of the data it needs, and is therefore not valuable yet for diagnosing issues since the data is incomplete?

 

[Terry@BMS]

Oh, interesting. So what is AvgIgn logging then? From engineering, I know that cells can't populate unless they pull data from somewhere, or calculate it based on other cells. Otherwise, a null character is used as a place holder.

Is it just running calculations without all of the data it needs, and is therefore not valuable yet for diagnosing issues since the data is incomplete?

I plugged in a temporary internal calculation there early on and forgot to remove it. It should always just reflect 0 but the data there now is not useful to anyone and unrelated to ignition advance.

 

[Revvdmedia]

Busted! Lol

 

[Mr. Tech]

I plugged in a temporary internal calculation there early on and forgot to remove it. It should always just reflect 0 but the data there now is not useful to anyone and unrelated to ignition advance.

Thanks for the confirmation! I was wondering why my avg ign looked horrendous hahaha.