OK. So surprised we have a Learning View thread without having a discussion on what the values mean!
First up: AF#1(and AF#2 for H6) Learning
The values are Long Term Fuel Trims which is actually a reflection of Closed Looop Fuel Compensation. The O2 sensor has constant feedback to maintain stoich(14.7 on petrol) fuel mixtures and that compensation is monitored by the ECU. It then determines a bell curve of the compensation values across a range of airflow values. So in Zac's tune the +12 means at idle, the ECU has applied +12 compensation as the most common bell curve value which is typical of a vacuum leak OR an exhaust gasket leak which results in oxygen not being measured by the MAF sensor having the O2 sensor run lean so the ECU trends to add fuel.
Just because you have values other than zero, does not mean you have an issue, it means your car is achieving optimal fuel mixtures
This applies to the first 3 of the AF#1 ranges, the red or blue means the ECU is running the target air to fuel ratio. It does not mean it is running lean or rich.
The important one is the D range as this applies the closed loop learnt range to the entire MAF scaling from D range value to the end of the MAF scale. So on a stock tune for a 2.5T, the value is from 40 to 80g/sec with 80g/sec being the typical range where 0psi occurs on spool. 2 Litre and 3L have slightly different values for the D range. A value of -10 in the 3rd range can influence spool as well even if 4th range is 0, as the ECU tries to smooth out the transition from -10 to 0 on a timer.
2nd: IAM
In the ECU software, there is two timing tables. Base Ignition Timing is a timing table designed for a bad batch of fuel as a worst case scenario and is when IAM is on zero. While there is also a timing value known as Knock Correction Advance(KCA) which is a table which adds ignition timing to the base timing value to have a total ignition timing value when IAM is on 1.00. The closer the Knock Correction Advance Value is to 0, the more likely you are to have an IAM change. Most tuners use values above 8(stock has values of up to 18 in some tunes!) so rarely see an IAM drop.
By setting the KCA table lower on lower values than stock, you are more likely to see an IAM drop BUT this has an advantage
There is also two fuel tables, Primary Fuel table which is the one run under normal conditions. There is also a Failsafe Fuel table which is for when IAM drops. Factory sets this at 0.35 IAM and the ECU has to drop to IAM of 0.349 before it will activate. I set mine at 0.751 so it only needs to drop to 0.75 before activating so if an issue is detected, the IAM drops to add fuel and pulls only a small amount of timing in comparison. Pull too much timing from the IAM being 0.35(2/3rds of KCA advanced timing)
So how does the IAM influence timing? In Zac's case 0.9375 is 15/16th's of 1.000 so in essence the Knock Correction Advance tables only applies 15/16ths of the total KCA timing. If the KCA value had been flat 16 degrees, then it would only be pulling one full degree of timing across the whole map and the blue values is the timing being added back in so the equivalent if IAM had been 1.00 would have pulled -0.75 in all the blue areas and the single red area would have been roughly -2.1
Zac's tune actually has an IAM value of 4 tapering down to 2.11 on boost as the EJ20y commonly has issues with the Camshaft solenoid filters blocking and inducing knock so since 15/16's of 2.11 is 0.125 of a degree, the ECU has actually learnt to pull 0.125 of a degree of timing across the map on boost and learnt to add more timing in Fine Learning Knock Correction as it attempts to return to IAM 1.000 so it has added timing in all of the blue areas. The single red area comes up to a total of less than -1.4 degrees of timing being pulled if IAM was on zero.
Suddenly, an IAM drop is not as 'serious' as it looks
Personally, if the EJ20y camshafts developed a problem and IAM drops to 0.75, pulls the 0.5 degrees of timing and then apllies the Failsafe Fuel map values fuel, so it wont suffer from pre-ignition from heaps of timing being pulled at IAM 0.35 with lots of fuel suddenly added in. If IAM continues to drop below 0.75, with slightly less timing and more fuel, then the Boost Disable table kicks in and disables boost... I get accused of having 'dangerous' tunes but the reality is, I tune for safety margins... the ECU logic from subaru is there ripe for the picking
Reason behind this? I drive in rural areas a lot, I have bought some NASTY claimed 98 fuel and IAM dropping to 0.75 saved my engine, it pulled the right amount of timing and added the right amount of fuel. Try finding a tuner who has mixed a litre of kero and litre of diesel sump oil into 91RON fuel to find the worst case scenario tune(IAM target of 0.00 with boost disabled, car ran completely knock free within 30 seconds after an ECU reset of IAM back to 1.00)
Fine Learning Knock Correction:
If IAM is on 1.00 then FLKC is a memorised pulled timing value that is applied between ranges. g/rev i the amount of air being sucked into two cylinders on a H4(or 3 cylinders on a H6) on each engine revolution(on a 4 stroke engine). So values of less than 1.4 are typically manifold vacuum under light throttle, with values over 2.8g/rev being over 15psi in most cases.
