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Old 10-29-2011, 08:48 PM   #1
MakuseruSukotto
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Default Fine Knock Learn & Feedback Knock.

05 WRX running the new v310 Stage 1 @ 93oct.

So from what I understand it is bad to have either one of these values read anything other than 0.

Well I took a trip today down to Atlanta. (250 miles or so) I was monitoring some values, and noticed both values would drop below 0.
Sometimes it would just be down to .3. Other times it would go down to 2.13.

Now is this bad? And if it is, how bad is it?

Here are some spreadsheets of logs.
https://docs.google.com/spreadsheet/...hl=en_US#gid=0
This was just going down the interstate, 70-80mph or so.



Also, don't know if this is related to this or not. But as I was coming back, I would be in 5th gear, 3k-3.5k rpm if I tried to accelerate the car would feel like it was just bogging down, almost lurching around, jumping. Just felt terrible, not much power. 4th gear did the same thing going up some mountains. But 3rd gear felt fine, like it had full power. (I did get to rev 3rd to 5-6k, where as the others I couldn't get it that high)
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Old 10-29-2011, 10:42 PM   #2
Black94Snake
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subscribed. My datalogs sow the same thing.
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Old 10-30-2011, 10:00 AM   #3
Cobb Tuning
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Quote:
Originally Posted by MakuseruSukotto View Post
05 WRX running the new v310 Stage 1 @ 93oct.

So from what I understand it is bad to have either one of these values read anything other than 0.

Well I took a trip today down to Atlanta. (250 miles or so) I was monitoring some values, and noticed both values would drop below 0.
Sometimes it would just be down to .3. Other times it would go down to 2.13.

Now is this bad? And if it is, how bad is it?

Here are some spreadsheets of logs.
https://docs.google.com/spreadsheet/...hl=en_US#gid=0
This was just going down the interstate, 70-80mph or so.



Also, don't know if this is related to this or not. But as I was coming back, I would be in 5th gear, 3k-3.5k rpm if I tried to accelerate the car would feel like it was just bogging down, almost lurching around, jumping. Just felt terrible, not much power. 4th gear did the same thing going up some mountains. But 3rd gear felt fine, like it had full power. (I did get to rev 3rd to 5-6k, where as the others I couldn't get it that high)
Skimming through your log, you have some learned fine knock correction at low loads (around 1.0 g/rev or less). This is normal. Where it can be a problem is when you start seeing consisent multiple counts (-2.8, -4.2, etc.) or you see the correction (feedback or fine) at high load that is not due to mashing the throttle or lifting abruptly off the throttle. Or if the DAM drops after it has learned up to its max value of 16 other than after reflashing a map, resetting the ECU, or disconnecting the car's battery.

I would try to get a log of the "lurching" that you are experiencing. Don't make giant logs - they are difficult to go through on google docs and a bunch of highway driving, etc. is not generally useful. Try just to start the logging just before the issue and stop it a little after.

Also, the best thing to do is to get a log with the car under some load, such as a 3rd gear wide open throttle run from 2000 RPM to near redline (if you can do so safely). Our AskCobb video describes this process:

Bill
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Old 10-30-2011, 12:33 PM   #4
MakuseruSukotto
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Sorry about that long log, I just didn't know when either value would spike down.

I'll try and get some logs of the stuttering.

I've done a few 3rd gear pulls and aside from not hitting target boost everything is fine. No FKL or FK.
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Old 11-05-2011, 08:15 PM   #5
MakuseruSukotto
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Ok, I was finally able to get the "stutter" in 5th gear.

I tried to hide all rows that didn't really apply to it so it would be smaller.

This was on the highway in 5th gear, when ever I put my foot down like to pass, it just would kind of stutter towards the end. Didn't feel right at all.

Here's the log.

https://docs.google.com/spreadsheet/...hl=en_US#gid=0
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Old 11-05-2011, 09:28 PM   #6
Black94Snake
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i only looked quickly, but I dont see anything in your datalog that shows your car "shuttering" but then again, the d-log resolution on the AP is friggin terrible...

Is your BPV working properly? your "shutter" could be a stuck BPV that is causing cavitation in the intake tract, and messing with the MAF and AFR's
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Old 11-05-2011, 11:16 PM   #7
MakuseruSukotto
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Quote:
Originally Posted by Black94Snake View Post
i only looked quickly, but I dont see anything in your datalog that shows your car "shuttering" but then again, the d-log resolution on the AP is friggin terrible...

Is your BPV working properly? your "shutter" could be a stuck BPV that is causing cavitation in the intake tract, and messing with the MAF and AFR's
Stuttering. The only other time I've felt something like this is in my old ford ranger when I had some plug wires go bad and I was misfiring. But 3rd gear pulls feel great in the WRX right now. How would I know if my BPV is working properly or not?
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Old 11-06-2011, 12:48 AM   #8
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Your airflow readings seems too high relative to the boost reading (~11psi). Check for boost leak?
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Old 11-06-2011, 08:05 AM   #9
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Quote:
Originally Posted by MakuseruSukotto View Post
Ok, I was finally able to get the "stutter" in 5th gear.

I tried to hide all rows that didn't really apply to it so it would be smaller.

This was on the highway in 5th gear, when ever I put my foot down like to pass, it just would kind of stutter towards the end. Didn't feel right at all.

Here's the log.

https://docs.google.com/spreadsheet/...hl=en_US#gid=0
When you say towards the end, was it after you started to lift off the throttle? Or did you lift off the throttle after the stutter happens?

Bill
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Old 11-06-2011, 01:14 PM   #10
MakuseruSukotto
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Quote:
Originally Posted by Cobb Tuning
When you say towards the end, was it after you started to lift off the throttle? Or did you lift off the throttle after the stutter happens?

Bill
I lifted off after it did it for ten seconds or so. It was doing it at wot.
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Old 11-06-2011, 02:09 PM   #11
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Quote:
Originally Posted by MakuseruSukotto View Post
I lifted off after it did it for ten seconds or so. It was doing it at wot.
It looks like your clutch is slipping. You can see in the log how RPM drops while you at WOT. It is common to notice this in the higher gears rather than low. May be time for a new clutch.

Bill
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Old 11-06-2011, 08:11 PM   #12
MakuseruSukotto
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Quote:
Originally Posted by Cobb Tuning View Post
It looks like your clutch is slipping. You can see in the log how RPM drops while you at WOT. It is common to notice this in the higher gears rather than low. May be time for a new clutch.

Bill
You mean how it kind of fluctuates up and down a few hundred RPM? That's how the car feels when ever its happening, like its going up/down in power. But the clutch feels fine in every gear.
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Old 11-07-2011, 12:10 AM   #13
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From the ignition and WGDC numbers it Looks like you are running the "Stage1 91 v310" map?

Almost 10 seconds at full throttle at 3000rpm and RPM hardly went up...


The Engine Load values are way too high for 10-11psi. You shouldn't see those load numbers until you boost beyond 16psi.


If you have the stock intake then it could be the MAF, or a boost leak. Either way, I think you are running really, really rich.
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Old 11-07-2011, 09:33 AM   #14
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Quote:
Originally Posted by MakuseruSukotto View Post
You mean how it kind of fluctuates up and down a few hundred RPM? That's how the car feels when ever its happening, like its going up/down in power. But the clutch feels fine in every gear.
Airboy has a great point. You need to get a pressure (or smoke) test of the intake tract done ASAP.

Bill
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Old 11-07-2011, 09:44 AM   #15
MakuseruSukotto
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I'll look into doing that very soon.

I really appreciate the help guys.

Could a possible boost leak also stop me from hitting target boost? (since that's been happening as well)

Last edited by MakuseruSukotto; 11-07-2011 at 10:14 AM.
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Old 11-07-2011, 11:52 AM   #16
Black94Snake
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a boost leak WILL stop you from hitting target boost. The ECM only allows for small corrections in WG DC to fix boost error. its not going to make a 5PSI correction...
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Old 11-07-2011, 12:01 PM   #17
Cobb Tuning
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Quote:
Originally Posted by MakuseruSukotto View Post
I'll look into doing that very soon.

I really appreciate the help guys.

Could a possible boost leak also stop me from hitting target boost? (since that's been happening as well)
Certainly can. Although not hitting target boost does not necessarily mean you have a boost leak. In this case, though, there is other evidence in that load is too high. You need to verify that you have a boost leak (via pressure/smoke test), fix it, and then go from there.

Bill
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Old 04-25-2015, 09:49 PM   #18
walsh
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Default 09 forrester xt fine knock learn of-1.05

Hello, i am having a fine knock learn reading of -1.05 at around 5000 rpm. i just want to make sure this isnt a bad thing and that it isnt hurting my car. The fine knock learn goes back to 0 at 5225 rpm and stays at zero until redline. Thanks!
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Old 04-25-2015, 11:04 PM   #19
snoopy_sti
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So the simplest way to explain it is your car had a single knock event at one time. It originally pulled 1.4 where you are seeing the 1.05. Then it no longer heard the noise so it is adding the timing back in. So you are fine. Just watch it learn itself away it will decrease to .70 then .35 and be gone. If it hears the noise again though it will populate to -1.4
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