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Discussion Starter · #1 ·
This is an example, ..base spark will be higher at times than actual
Had one 2.0
st knk, seemed like a fluke at WOT, only once, then did the next
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short WOT, seemed fine..
Anyone that knows more than I, go ahead and yap at me so I can learn..
Diablo sport i3 platinum
93 octane tune (Diablo tune)
Increased fuel to 1.0 at all rpm ranges, thought with increased air flow, richen it up a bit..
93 octane gas
CAI, 3" high flo catted midpipe, borla s type cat back
 

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The Bacon Hauler (‘12 Cop Charger)
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The key to identifying real, addressable KR will be its existence in multiple, consecutive data logs in the same RPM range. So if that one 2 degree spike were to recur in subsequent data logs in roughly the same RPM range, that would be something you would want to address.

Another indicator that spike isn’t necessarily something to do anything about (IMHO) is its shape, for lack of a better term. When it immediately spikes and then ladder steps down like that, I believe it is an indicator of false knock. That is my opinion based upon my experience though, and it would seem to be backed up at least a little by its absence in the other data log.

Keep datalogging, you can never have too much data. Don’t forget to fill in the info pop up with gas type, gas octane, and any tune mods you have for that log, as that will come in handy later when you’re trying to find logs that apply to some future condition you’re researching.
 

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Discussion Starter · #3 ·
Hey thanks, I figure there's a glitch here and there, 4 long data logs, that was the only st knk.. I wondered about the precise fuel combustion, lean, rich, some magic number.. Right now, I think it runs great, I'm in a target zone, no harmful spikes or LT KNK, It seems like the actual spark often runs below the demand, base..so that could be the fine point of enough spark to burn fuel..
Thanks again..
 

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The Bacon Hauler (‘12 Cop Charger)
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9,439 Posts
Hey thanks, I figure there's a glitch here and there, 4 long data logs, that was the only st knk.. I wondered about the precise fuel combustion, lean, rich, some magic number.. Right now, I think it runs great, I'm in a target zone, no harmful spikes or LT KNK, It seems like the actual spark often runs below the demand, base..so that could be the fine point of enough spark to burn fuel..
Thanks again..
As I understand it, the actual spark should not be less than base spark at WOT unless some KR has been applied, and if you add the amount of the most recent KR (ceiling) to the actual, you get an amount that equals the base.

But I could be off on that...
 

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The Bacon Hauler (‘12 Cop Charger)
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As I understand it, the actual spark should not be less than base spark at WOT unless some KR has been applied, and if you add the amount of the most recent KR (ceiling) to the actual, you get an amount that equals the base.

But I could be off on that...
disregard that part about base spark, etc. I just took a look at my datalogs to verify, and what I was thinking is not what I described above. I'm thinking it must be (base spark + spark advance) - KR = actual spark, but I don't have the spark advance PID in any of my most recent logs.

IDK, don't listen to me, I can't be trusted, I'm still in mourning over the loss of my beloved Bacon Hauler. :cry:
 

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2010 Challenger 6M- Brilliant Black, 426 stroker, Hellcat rear cradle, ZF 3.90 diff, DSS 1 piece
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For what it's worth: when i add timing using HP tuners there are other factors ("modifiers") that the neural network uses to determine actual spark. MAP and MAT are the two that come to mind.
When I was getting my tune together I initially did WOT pulls from a rolling start in 2nd on the highway when empty.
This was a good method to get a base tune, but the dyno is where you can finalize it.
Load and resistance can be applied to keep the engine in a certain range longer for better data logging.
The way I did it was to monitor AFR and keep it as close to 12.5 as possible, then add 1 degree in each range until I saw knock. Then back off a degree.
 
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The Bacon Hauler (‘12 Cop Charger)
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That’s the way to go for sure, but it requires a wide band though.

Although, there is a theory out there, pretty much created by me, but nonetheless a theory, that as long as the car is pretty close to stock, the narrowband AFR can be trusted. It’s only when lots of performance mods have changed the VE by a significant amount that the narrowband can no longer be considered accurate.

But since the consequences of fouling things up exists if that theory is followed, I am reticent about suggesting anyone else follow it.
 

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with the bolt-ons the OP has it's probably pretty close to stock fuel trims.
I consider a wideband a necessity when tuning though.
 

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The Bacon Hauler (‘12 Cop Charger)
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with the bolt-ons the OP has it's probably pretty close to stock fuel trims.
I consider a wideband a necessity when tuning though.
As Ed McMahon would say, “You are correct, sir!
 

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Discussion Starter · #10 ·
Thanks again for all the discussion, just re read it..just did manifold gaskets, pcv replacement and will be adding catch can.. Posted in different thread..

 
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