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*** Knock, do you have any?


LittleBlueGT

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I too only log KS and then do a lv to see if anything is learned. If I ever get a knock it almost never shows up on the lv on the highend..even though I keep fine learning active at higher loads, I mainly see learned knock at cruise.

 

Truth is, no one knows exactly when fbkc or flkc or iam is active...the ecu decides.

 

Where I really notice it is in my buddies 04 STI...there is no knock sum option and on wot runs it is always fbkc reactive to a wot knock event.

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It's been so long since I've seen any real knock in my logs, it's hard to remember.

 

This means to me...

 

You don't log.

 

You don't ever drive in boost.

 

Your tune is anemic.

 

Because, one way or another, once in a while, knock simply happens. Knock sums are a part of everyday life. Variations in fuels, temperatures, and loads are a part of life.

 

A good tune, and frequent review of logs, will occasionally populate a cell here and there in the FKL table with minor numbers, which when checked another time will be gone. But, if you check frequently and NEVER see knock... you may as well have a Honda.

 

I say this so others don't get the idea that TOTAL elimination of occasional knock means you have a perfect tune, and that seeing knock with low numbers means you have a bad tune. The best tunes can knock... for a variety of reasons. Shift knock. Doing stupid stuff with your throttle. Driving along at 70 mph and down-shifting then mashing the pedal, for example. Failing to completely warm the car up... not just having the coolant reach thermostat-opening, and hammering it. Ripping up a steep incline on a wicked cold day. Stuff.

 

Knock happens. Know why. Otherwise how will you be able to analyze it and know the difference between destructive knock and normal, and apply appropriate corrective measures, whether it is correcting your own behavior or the tune.

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I too only log KS and then do a lv to see if anything is learned. If I ever get a knock it almost never shows up on the lv on the highend..even though I keep fine learning active at higher loads, I mainly see learned knock at cruise.

 

Truth is, no one knows exactly when fbkc or flkc or iam is active...the ecu decides.

 

Where I really notice it is in my buddies 04 STI...there is no knock sum option and on wot runs it is always fbkc reactive to a wot knock event.

 

Not exactly. While, of course, the ECU decides, the decisions are clear-cut. This explains the details:

 

http://www.romraider.com/forum/topic1840.html

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i have a question. so i was dyno tuned with my amr 20g/dw 850's/65c/fmic made about 320whp to redline. i put a process west tmic on a week later and got high rpm/load knock, about -3.6 degrees. okay i kinda expected it, decreased timing in that area in KCA from 5.27 down to 2.11 with a 11.99 base timing iam 1. knock is completely gone. i'm tuned to 20psi and i adjusted wgdc to target that with the tmic, but since im pulling that much timing should i just drop the boost and run more timing? it's a 20g, 20psi and above is its best performance right? afr's 10.8
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I don't think there is any 1 correct answer. Some people like to tune for more boost/less timing, slightly leaner afr (I do). Others run less boost more timing and little bit richer afr.

 

You have to figure out which combo works best for you and your setup.

 

What fuel are you running? 93 octane?

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93. i didn't think about running less boost since it's a 20g, at 20psi it's moving a lot of air. it tapers to 16-17psi by redline. i was tuned to 11.2 afr's with the fmic but i richened it a bit when switching to the tmic and noticing the knock, perhaps i should slowly readvance kca till i get a 1.41 here or there....
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bmx, I'd think you could easily run 20-22 psi and maintain 19-20 up top. A properly configured fuel table and 11.4 AFRs are more correct than 10.x... rich makes knock, too. Lean then adjust timing.

 

Also, don't forget AVCS affects knock, too. Set your boost, get the AFRs right, AVCS right, and once knock is eliminated timing is what it is.

 

An AFR meter on the column is your friend.

 

Stock plugs for a DD is my choice.

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My avcs was os tuned when i had a fmic(now tmic), should i leave as is or return to factory? I do have a wideband, im hitting 10.8 as i set in the ol tables. I will up it back to 11's

 

You can't go too wrong with the factory AVCS settings. That said, with your new turbo, you can think about adding in some AVCS higher up once everything else is steady. The factory AVCS reflects the restrictions of the OEM turbo's hotside.

Edited by SeeeeeYa
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the response is definitely much improved for around town driving. having a bit leaner afr's will also improve spool. i went from a racerx to a process west.... right off the bat overboosted as expected and -3.8 knock in high load and rpm cells. I fixed the duty cycles so it peaked at 20/21. do you suggest i revert back to the original afr that was tuned with my fmic and then work my way back up on timing slowly? or other way around
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the response is definitely much improved for around town driving. having a bit leaner afr's will also improve spool. i went from a racerx to a process west.... right off the bat overboosted as expected and -3.8 knock in high load and rpm cells. I fixed the duty cycles so it peaked at 20/21. do you suggest i revert back to the original afr that was tuned with my fmic and then work my way back up on timing slowly? or other way around

 

Yes. Set your boost and AFR, then, as you say, work the timing back slowly and don't worry so much what the precise values end up being as long as you are knock-free.

 

A good tune will be best with AFRs nearer mid-11s, 10s are pig-rich and causes issues, not solves them.

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duly noted. looking back, my original tuned afr was 11.13 target with a base timing of 11.99 and kca of 5.27. at those settings i was knocking about -3.8* at above 3.3 load range :eek: I hit around 3.7 loads when logging. Currently I'm set at afr 10.8, base 11.99 and kca of 2.11 avcs unchanged...with these settings not a hint of knock anywhere. i will work on this when i get home tonight, thanks
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however i thought the *general* rule for fmic verse tmic is that afr's should be richer with tmics. i base this on reading nasioc badnoodle's tuning guide

 

An engine's combustion doesn't know or care about your intercooler. Also, the "general" rules are morphed slideways in consideration of ineffective and ill-managed tuning, and do not reflect the science. People generally don't want to be responsible so they give people a path even a dummy won't screw up. Those people shouldn't be tuning in the first place, "pro" or not.

 

Here is a good discussion... listen to Rifts. Really. http://forums.nasioc.com/forums/showthread.php?t=673369&highlight=leanest+afr

 

Listen carefully to post #23, and this: "Remember.. timing is just a crutch for poor VE."

 

Once you get the balls to try leaner instead of being intimidated by misinformation, and see how much better your car runs, you understand.

 

Again, don't consider a timing NUMBER some kind of goal... timing is what you adjust to get all the rest working best, and knock-free.

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