[IRTsti]

1.5 was low at 2500 rpms starting point and scaled slowly as rpms increased
7.5 was highest reading at 6k rpms.

I just realized i dont have the definitions for Fine learning or Feeback knock. I only have Knock correction advance which is what i logged last night.

[bluedemon_II]

If you downloaded Romraider then you have the most up to date def. You chose the Fine learning parameters when you are already reading form the ecu. Before that they wont appear in the screen. Really we cant tell you an exact number of what KC you should have because the KC map on the ecu is pretty much random numbers. Yo would need to flatten out the KC map in the high load points to see if you are knocking etc.

[gabedude]

Originally Posted by kpnorton

You want to watch both.

FBKC is a timing retard in response to a "real time" knock event (e.g. the previous combustion cycle). It is a reactive knock suppression function.

FLKC is a stored parameter based on the presence of knock at similar load and RPM in the past. It is a preemptive knock suppression function.

They both can tell you where to make timing adjustments, however FBKC is a bit more precise for locating where knock occured (load & RPM) in that you see it in response to an actual event. That said FBKC can occasionally occur spuriously and/or result from a rapid change in load (shifting). FLKC is less precise for locating the point of onset (load & RPM) in that the FLKC table is coarser (fewer rows & columns) than the timing maps. However, the FLKC values will change over time and with finer precision so they can give insight into the intensity of the knock and are less likely to be spurious.

Keep in mind that FLKC and KBKC are additive.

How much correction were you seeing?

Not entirely correct.

FBKC = instaneous response to a knock event that just occurred. Example for a stock 07 STI is that the ECU pulls 1.4 degrees per knock event encountered. There is also a delay. So what you look for is increasingly large negative values:

EX of bad knock: -1.4, -2.8, -5.6, etc

EX of slight knock (one knock event ocurred): -1.4, -.7, -.35, 0, 0, etc

The same applies for FLKC, however FLKC can be positive and may have a starting learned value pulled (or added if IAM is not at 1). You must look at the trend and know what is in you FLKC table. Use Learningview tool to see this before you log.

FBKC and FLKC can both occur at the same time as well. Remember that FLKC is the trigger for the ECU to enter into rough correction (where a global IAM adjustment is made dependent upon knock occurring right then as all learned timing gets reset for a global correction: IAM is reset to it's intial value (0.5 for stock mapping) and it flip flops based on absence or presence of knock). Your IAM may do something like this:

IAM = 1. Knock makes FLKC go past -4 in a cell in the DA table that can trigger Rough Correction (IE: The DA cell has a 6 in it). IAM may do this:

Enter rough corretion-> FLKC table reset -> IAM reset -> IAM = 0.5 -> no knock -> FLKC grows to +4 -> IAM step value is .25 -> IAM = 0.75 ->FLKC table reset -> Car encounters knock -> FLKC goes to -4 (flip flop) -> IAM step value halved to 0.125 -> IAM = 0.625 -> FLKC table reset -> no knock -> FLKC grows to +4 (flip flop) -> IAM step value halved to 0.0625 -> IAM = 0.6875 -> FLKC table reset -> IAM stable, some positive and negative values of FLKC now should show up. Car runs smoothly.

RomRaider • View topic - Subaru's knock control strategy explained

The same example can be held for 16 bit ECUs, but your IAM is an integer value instead of a float (16 max, default starting 8, default step 4). There are still two times that the step value can get halved when in rough correction (during a flip flop).

I think it is imperative that people tuning a Subaru with the stock ECU understand how the levels of knock protection work and how final timing is derived.

Standalone knock control is much simpler.

Also, forget about Knock Correction. It is totally dependent upon several factors (the DA table value, IAM, FLKC and FBKC). I don't even log Knock Correction. Only FLKC, FBKC, IAM and total ign timing as far as timing goes.

[Maverick31]

Sorry to thread jack, but how exactly do you scale your maf?

[nhat]

there are a couple different ways...hop on over to romraider forums and read up!

RomRaider • View forum - Tuning Discussion

[bluedemon_II]

Basically you look at AF learning and corrections and get them into a certain number by scaling the maf. Its something that will take a few tries but once you have mastered its pretty easy. Sometimes you could play with the injectors but that is not advised.

[Maverick31]

Thanks guys, that helps.