No single reference to well know offsets for IAM and EL?

[Ziggyrama]

Hello all,
I am ofcourse battling the same issue that everybody else has or will battle and that is the location of my IAM and engine load offsets in my 04 ECU. Do we have a place to post a location if we find it? Seems like we all trip over this and I cannot find this info anywhere. We really should share this data especially if it's been verified as a correct location. So, I am searching for my offsets, 04 USDM WRX:

Year: USDM 2004 WRX MT
Case ID: AH802 and AH794
Internal ID: A4TF400E and A4TF520F

If you have any info, please post. Hopefully we can compile enough data for it to be a sticky.

[merchgod]

Both are IAM 0x20120 and Load 0x200EE. I'm slowly compiling a list. Enginuity's logger was just released. Down the road it will have the ability to automatically choose IAM and load and some other parameters based on your ecu.

[Ziggyrama]

Merchgod, thank you for replying. Much appreciated. Now I can actually do some meaningful logging. Awesome!!!

[Ziggyrama]

Ok, I did some logging and the values don't add up to me. I have set IAM and engine load to 0x20120 and 0x200EE respectively. I attached my log. What does not make sense to me are the load values. I am generating load values upto 4.5 which seems too high for straight line pull in 2nd gear. Does that seem right? Also, the IAM is logged at 16. My map advance multiplier is set at 12. How can that be? What am I missing? The ignition timing also looks suspect to me. Based on my map, the timing is 5 degrees higher than what my map describes. It might be related to funky load values but I had to ask.
Any help in clarifying this is much appreciated.

[merchgod]

The IAM you set is the initial IAM after a reset. The advance multiplier is dynamic based on knock. So, after a reset, if you have it set to 12 it will start there and then move up and down based on knock in a range of 0-16. 16 is max, so that means that you will be using all of your ignition correction map. If it was 8, you would be using 50% of the values of your correction map.

It is possible to hit an engine load of 4.5 (16bit ecus) depending on your mods. Modifying the MAF scaling also can affect the engine load value.

Remember, total timing is your base timing + (ignition correction x (advance multiplier/16)). You are running an advance multiplier of 16, so you are using 100% of the values from the ignition correction map. Keep in mind that there are other compensation tables that can affect your total timing as well.

[Ziggyrama]

Thank you for replying. What you're saying makes sense. So, in my case, if my timing is set at 6 with max KC value at 7, maximum timing I could be running is 13, if my IAM climbed up to the maximum value. I did not occur to me that I would see the ignition advance value logged after the KC correction, not before. So, in the end, I should really look at the KC values as an indicator how well I am doing along with my IAM value. If they are running at maxed value, I am in good shape. Based on my log, looks like my car is pretty happy.

Currently, my map is scaled up to 4.28 load factor. I saw over 4.5 load values during my pulls which falls off the scale. How does the ECU treat this case? Does it use corresponding last map cell for the given RPM range to determine the value? Sounds like I should scale my map higher to account for higher load values.

Thanks a bunch for all the help. Much appreciated.

[merchgod]

If you exceed the last column or row then it simply uses the last column or row. Your KC is essentially your ignition correction that is being added to the base map. It is a lot more complicated than this, though, so don't expect it to match up perfectly to your maps, but if you see a significant drop in KC compared to what it should be then you were probably experiencing knock at that point. Some guys will change their correction map to say, all 10's, in the moderate to high rpm/load sites and then change their base timing so that the total timing remains the same. Then, when they are logging, if they see a KC of less than 10 then they know they probably had knock (or other compensation to timing such as those for coolant temp and IAT).

[Ziggyrama]

Yes, I have seen this approach before. It actually makes a lot of sense. Running through the numners after each log session and verifying the cells against the log is really time consuming. This really speeds things up. In fact, that is the first alteration I will do before I even attempt to rescale the load axis. This way I keep thing apples to apples and if behavior changes, I will know what effected it.

So, my next question I'd like to rescale my map to account for higher loads that I am seeing in my logs. I am logging 4.5 but my map goes up to 4.28. I would like to avoid redoing the entire map since that will have implications on other maps so can I just change the last load values to something higher like 4.6? I'd be running the same map values anyways so it should not have any effect, correct? Or will the ECU interpolation curve between the cells change too much since now the curve between last 2 values will change now that the map is in range?

In a case where I need to modify several columns, can I stretch the intervals in low loads and add granularity up top by mapping the ignition curve in something like excel and following the same curve with less values in low load range? This way the ECU interpolation should yield just about the same results, right?

Am I making sense?

[merchgod]

You can do it either way. Which is best depends on where you want/need the greatest resolution to be which would be highly dependent on your vehicle, its mods, and your tuning methodology. There are a lot of posts about this Nasioc, this forum and the Enginuity site.