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      08-31-2012, 09:16 AM   #1
BADS335
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Knock Retard after 5k rpm (Procede logs inside)

Hello, I have been experiencing this for some time regardless of fuel, map, settings.

This log is Stage 2 (Procede Rev3 5-23 maps OLF at 85%). Mods include DCI, Catless DPs, Cat-back exhaust. Ambient was about 91*F. 93 octane fuel. I know IATs are high, but I have seen the same KR at much lower IATs in the past. But this is probably worst case. Any suggestions or thoughts? I would hate to lower anything globally (IE boost or timing) since it is only occuring above 5k. I suppose I could try lowering IC way down to see what it does. But I have seen this with 100 octane in the past too. So I am thinking it is something else.
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      08-31-2012, 10:18 AM   #2
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You have a huge boost swing when your timing drops like that. Maybe fix that?
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      08-31-2012, 10:32 AM   #3
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Quote:
Originally Posted by themyst View Post
You have a huge boost swing when your timing drops like that. Maybe fix that?
Can you explain a little more? The way I think I understand what you are saying is that the boost should taper down more after 5k instead of creeping back up?
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      08-31-2012, 10:43 AM   #4
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Quote:
Originally Posted by BADS335 View Post
Can you explain a little more? The way I think I understand what you are saying is that the boost should taper down more after 5k instead of creeping back up?
Exactly.
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      08-31-2012, 10:59 AM   #5
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Actually, after looking at the boost alone (I had way too many overlays) there is no swing. It is a pretty steady taper all the way.
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      08-31-2012, 11:17 AM   #6
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I was looking at IC and it tapers closer to zero pretty aggressively after 5k. So I think my issue is too much timing up top.
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      08-31-2012, 11:22 AM   #7
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Quote:
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Actually, after looking at the boost alone (I had way too many overlays) there is no swing. It is a pretty steady taper all the way.
Yep, your boost is fine and smooth. If the knock retard is persistent when running 100oct, then it's unlikely to be an issue with software/tuning but rather a hardware issue. Could be as simple as a problematic plug/coil or as irritating as carbon build up in your valves/on your piston. When was the last time you changed plugs? Ever done walnut shell bashing?
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      08-31-2012, 11:28 AM   #8
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Quote:
Originally Posted by shiv@vishnu View Post
Yep, your boost is fine and smooth. If the knock retard is persistent when running 100oct, then it's unlikely to be an issue with software/tuning but rather a hardware issue. Could be as simple as a problematic plug/coil or as irritating as carbon build up in your valves/on your piston. When was the last time you changed plugs? Ever done walnut shell bashing?
I just did the walnut shells and plugs a couple months ago. I would hate to swap out all the coils to find out it was not a coil issue. One is fairly new as one did go bad.

Any other way to diagnose the KR without swapping hardware?
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      08-31-2012, 11:40 AM   #9
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Quote:
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I just did the walnut shells and plugs a couple months ago. I would hate to swap out all the coils to find out it was not a coil issue. One is fairly new as one did go bad.

Any other way to diagnose the KR without swapping hardware?
Not really unfortunately. You essentially diagnosed the nature of the KR by running 100oct fuel already. I presume the same KR exists at lower boost levels as well?
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      08-31-2012, 11:43 AM   #10
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Quote:
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Not really unfortunately. You essentially diagnosed the nature of the KR by running 100oct fuel already. I presume the same KR exists at lower boost levels as well?
I have not tried at lower boost levels. I was going to set the Ignition Advance MAP1 table at 4750+ all load levels to -12 and see what happens. Maybe lowering boost is a better method?
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      08-31-2012, 11:47 AM   #11
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Quote:
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I have not tried at lower boost levels. I was going to set the Ignition Advance MAP1 table at 4750+ all load levels to -12 and see what happens. Maybe lowering boost is a better method?
Yes that's a much better method that running negative ignition advance
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      08-31-2012, 11:49 AM   #12
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Nevermind. I can't edit the table anyhow.
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      08-31-2012, 11:53 AM   #13
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I will set start boost to zero and see if that makes any difference.
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      08-31-2012, 12:10 PM   #14
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Nevermind. I can't edit the table anyhow.
Yes you can. Another simpler option would be to just upload a more conservative map file (stage 0 for instance).
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      09-04-2012, 08:42 AM   #15
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I dropped the boost on stage 2 and it did the same thing. I can try stage 0 and see if I get the same thing. But I am starting to believe a coil is on its way out as well. Not sure why this would cause KR instead of missfires though.
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      09-04-2012, 08:48 AM   #16
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At 4500 rpms I see there was slight wheel slippage and if you have DSC on it will reduce boost and timing. Did u have DSC fully off?
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      09-04-2012, 09:52 AM   #17
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At 4500 rpms I see there was slight wheel slippage and if you have DSC on it will reduce boost and timing. Did u have DSC fully off?
Yes, fully off. Even still, it would not give KR. Just reduce actual advance.
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      09-04-2012, 11:12 AM   #18
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Another thing I find odd is it looks the same every time. No KR anywhere else in the band. Only above 5k.

Maybe I should buy a coil and swap out one at a time till it goes away?
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      09-29-2012, 02:18 PM   #19
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Wanted to bring this back up for more opinions. Thinking of getting a coil soon but want to have more confidence that will fix it before I buy yet another part I do not need.

Thanks
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      09-30-2012, 09:19 AM   #20
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It won't be hard to sell barely used coils.

Also might want to check fuel pressure on the low side during the pulls. High RPM problems can typically be inadequate fuel delivery or weak spark.
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      10-02-2012, 11:00 AM   #21
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Quote:
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It won't be hard to sell barely used coils.

Also might want to check fuel pressure on the low side during the pulls. High RPM problems can typically be inadequate fuel delivery or weak spark.
If it was inadequate fuel, then the AFR would be way off. It is right where it should be. I do agree on the weak spark, but not sure how to check that.
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      10-16-2012, 07:48 AM   #22
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Ok, swapped each coil and logged each...same issue. I am out of ideas. I will try stage 0 today but I have doubts. Only other thing I can imagine is I have a valvetrain tick that may be resonating at 5k triggering the knock sensor (again, another issue that I have no idea what or how it started). But I don't feel it in the car. I only feel loss of power when it pulls all that timing.
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