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Old 05-25-2018, 07:04 PM   #26
PDXREALTOR
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Originally Posted by snowridewrx View Post
have you adjusted your af learning break points or disabled your D range? i am thinking this is your issue. here is a quote from cobbs tuning guide.

Disabling Learned Fuel Trims under Open Loop Operation

From the factory, all Subaru ECUs use four distinct learning ranges for learned long-term fuel trims (LTFT). These are known as "A/F Learning A/B/C/D" and can be logged or viewed in realtime while Live Connected to the ECU. The learned value being actively applied at any given time can be monitored by viewing the "A/F Learning #1" monitor. The three break-points given in the "A/F Learning #1" table will determine the thresholds between each range (A-B, B-C, C-D). The min for range A and max for range D are determined by "A/F Learning Modify Airflow Limit (Min)/(Max)" tables, respectively. Keep in mind that this is only the cap for when learning is active, the actual learned value will be applied at all times while above the C-D threshold value. This behavior can be problematic for aftermarket or performance tuning as minute MAF scaling errors under cruising conditions can have broad impact over the entire open loop range of operation.

Thus, we can disable learning in the D range by setting the "Max" table to just below the C-D threshold. This will still allow for the A, B and C ranges to be populated and used under various cruising conditions based on fueling errors between those breakpoints. For example, if the C-D breakpoint value is 50.00 g/s, setting "A/F Learning Modify Airflow Limit (Max)" to 49.99 g/s will disable the D range from being populated with learned values.

As the engine transitions through the various MAF g/s ranges for the A-D learned ranges, a smoothing factor ("A/F Learning #1 Range Smoothing Factor") is applied to blend between the two different learned values if the difference between the current A/F Learning #1 value and the current learned range is greater than the absolute value within the "A/F Learning #1 Range Smoothing Activation (Min. Abs. Change)". This is to help prevent immediate abrupt changes to the active A/F Learning #1 value being applied, such as if the previous range being referenced was +10% and the new range being referenced is -5%. This smoothing behavior can cause learned values from the "C" range to be carried into "D" range based on the smoothing factor, even if learning has been disabled for the "D" range. The activation threshold and smoothing factor are both adjustable, so you can change these behaviors based on specific tuning needs.

https://cobbtuning.atlassian.net/wik...r+Tuning+Guide
Great info! I've don't recall ever reading that about the transitional time. I looked it up in ATR and, it doesn't refer to what the value represents. I also looked a log real quick and sure enough with a 4% correction, my D range is being affected, though very minutely.

At 100 octane I would think the cruise timing can go up from the 93 octane tunes. I wonder what flex fuel runs timing at.
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Old 05-25-2018, 08:27 PM   #27
Sw20matt
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The COBB OTS maps come with the D range disabled and come adjusted to the 49.99 value.

I am currently running the COBB OTS Stage 1+SF map and will use the it as a "base" once I get started on my own tuning.
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Old 05-31-2018, 10:59 AM   #28
BubbaRacing
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Probably not what you guys are looking for but I noticed on my 17 i get false knock in cruising from ac kicking on and off. I can get -1.41 fine just from that
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Old 06-02-2018, 02:53 PM   #29
HawkwardWagon
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2006 WRX here on Stage 1 91 octane California piss v3.10

Only mod is a HKS catback... I'm having some of the same issues with low load knock events around 2500-3000 rpm. FBK up to -11.5 which is HUGE. With city cruising I've experienced up to -7, and on the highway is when I got the -11.5 FBK.

FKL has never gone below -1.4, and it's pretty much at 0 at all times.
DAM has always been 1.0, not a single deviation.

I have some WOT runs in 3rd gear on a smooth road. No FBK at all, and just a little bit of FKL. I haven't done any regular driving logs yet.

What do you guys think about these? Here are 3 different 3rd gear WOT runs
https://drive.google.com/open?id=1hk...7i7ZCXoaD_-StG
https://drive.google.com/open?id=1VF...iDyLF8GYGKzabx
https://drive.google.com/open?id=19U...iibJ1AmIKwZrN0

So common ways to diagnose the knock events would be...
1) Check engine bay for rattles
2) Get higher octane gas (Not sure where to get higher octane gas, other than adding octane booster to a tank)
3) Retard timing on the AP

Am I right?

Last edited by HawkwardWagon; 06-02-2018 at 03:17 PM.
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Old 06-03-2018, 11:55 AM   #30
Sw20matt
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Quote:
Originally Posted by HawkwardWagon View Post

So common ways to diagnose the knock events would be...
1) Check engine bay for rattles
2) Get higher octane gas (Not sure where to get higher octane gas, other than adding octane booster to a tank)
3) Retard timing on the AP

Am I right?
generally yes,

higher octane gas typically would be race fuel you would get in a 5 gal drum.
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Old 06-03-2018, 05:13 PM   #31
TurboQueef
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Quote:
Originally Posted by TurboQueef View Post
New update…

I put a go-pro under the hood and can hear distinct “knock-knock” just before seeing knock registered in my AP.

Initially I thought this knock was caused by the alternator or power steering pump.. cause it went away after removing the belt…. But come to find out.. my issue mostly occurs when engine is cold/cool as it is warming up…and my without belt test was performed with hot engine

I decided to check for slop in my timing belt… and after removing the cover and upon fondling the belt I can hear the same “knock-knock” as the belt is fondled upward. I believe the sound is caused by the tensioner pin hitting the dowel pin in the bracket.

I am running a GATES timing belt kit that has the non OEM tensioner… it has 9K miles on it.

I am planning to replace the tensioner to see if the “knock-knock” goes away.

Will keep you posted
Update: I pulled the engine due to high leakdown (ringland issue)... and found the timing tensioner bracket pin is worn. It seems this is normal condition but with the Gates (non OEM) tensioner there was enough slop to cause the knock sensor to go crazy under low RPM low LOAD warm up. Images below show the worn pin.



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Old 06-03-2018, 05:19 PM   #32
PDXREALTOR
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Quote:
Originally Posted by Sw20matt View Post
generally yes,

higher octane gas typically would be race fuel you would get in a 5 gal drum.
You can use xylene (expensive) or Torco or Boostane. I use torco in every tank to get ~100 octane

There is a mix sheet easily found on google for how much xylene to add.

I recently upped my torco and got knock, then added timing to remove it..... So again, too little timing can be an issue.
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