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phila_dot
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« Reply #15 on: April 12, 2013, 05:51:03 AM »
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I think you guys assume too much that all cylinders are equal.
They are not.
And if you don't have any timing pull, you are losing power, as some cylinders can easily have 3-4 deg more advanced timing.
Tested this on dyno as well, and everything is as expected.
I'll start by saying that I get what you're saying and I'm not arguing or disagreeing, but... Typical results I see: zwgru : 21* dwkrz : 4.5* zwout : 16.5* zwgru : 19.5* dwkrz : 0* zwout : 19.5* This is how I've found the best results. So, my question to you is, are you doing something else? Modifying something in KR? |
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prj
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« Reply #16 on: April 12, 2013, 07:05:34 AM »
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I'll start by saying that I get what you're saying and I'm not arguing or disagreeing, but...
Typical results I see:
zwgru : 21*
dwkrz : 4.5*
zwout : 16.5*
zwgru : 19.5*
dwkrz : 0*
zwout : 19.5*
This is how I've found the best results.
So, my question to you is, are you doing something else? Modifying something in KR? I don't get people's obsession with zwout, when zwout is the current output for a cylinder. What you see in zwout just depends on blind luck, it's not really useful for anything. Yes, one or two cylinders will be retarded more, but the rest will be advanced, making more power in total. You can also adjust KR... The fine balance is where about half of cylinders have some sort of correction. You don't want correction on all cylinders. My experience is with dyno testing and what makes the most power. Make some back to back runs and you will see what I mean. All these engines make peak torque and power with a little correction. Your quoted numbers and observations would be correct for a single cylinder engine, but most engines have at least four cylinders. |
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« Last Edit: April 12, 2013, 07:09:12 AM by prj »
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phila_dot
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« Reply #17 on: April 12, 2013, 08:03:19 AM »
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Understood, I used zwout for simplicity. Same reason generalized dwkrz rather than being cylinder specific. I do shoot for some correction here and there, but overall near zero.
Regarding the Op's question, street tuning, how many degrees retard for dwkrz are you satisfied with?
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jibberjive
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« Reply #18 on: April 12, 2013, 08:55:12 AM »
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You can also adjust KR...
Do you usually adjust KR, or do you usually leave it stock (on the 2.7t)? About how many degrees correction (on half the cylinders like you mention) do you feel is safe but powerful ? |
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prj
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« Reply #19 on: April 12, 2013, 08:57:12 AM »
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I aim for about 0.75-1.5 WKRM, as then the most knock prone cylinders get some correction, and the rest of the cylinders run more advanced ignition.
I've also found that this gave me the best result on the dyno.
It's pointless to have correction on all cylinders, that will just make less power. With knock control I sometimes adjust how much it retards on the first event.
That said, I have not done anything on my RS4 with KR, as the stock calibration seems quite good.
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jibberjive
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« Reply #20 on: April 12, 2013, 09:06:33 AM »
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Thanks for the insight and dyno experience.
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CoupedUp
Full Member
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« Reply #21 on: April 12, 2013, 12:33:03 PM »
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While I am green to most of this. Isn't it all just a wash?
If I have my tune currently pulling say, -6.5(average) on all cylinders but don't feel like that is "safe" and dial back 4-5 degrees to achieve -1.5(average) on all cylinders it's still achieving the same actual timing, right? The -6.5 would be causing ignition at say 10(hypothetical) degrees BTDC and the "dialed" back -1.5 would also be 10 degrees BTDC ignition.
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ddillenger
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« Reply #22 on: April 12, 2013, 12:52:28 PM »
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When timing is pulled there is a delay before it's added back. Running optimal values is better all around.
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Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your experience!
Email/Google chat:
DDillenger84(at)gmail(dot)com
Email>PM
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phila_dot
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« Reply #23 on: April 12, 2013, 01:25:35 PM »
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While I am green to most of this. Isn't it all just a wash?
If I have my tune currently pulling say, -6.5(average) on all cylinders but don't feel like that is "safe" and dial back 4-5 degrees to achieve -1.5(average) on all cylinders it's still achieving the same actual timing, right? The -6.5 would be causing ignition at say 10(hypothetical) degrees BTDC and the "dialed" back -1.5 would also be 10 degrees BTDC ignition.
Did you read this thread? For one, it's better to prevent knock than to react to it. KR will pull more timing to subside the knock than was necessary to avoid it. As DD said, it takes time to recover from retard. Also, the retard is adaptive, so dwkrz will be loaded with adapted values if learned in a particular load/speed range even in the absence of knock. Also, in the case of something going wrong, you preserve the headroom in max retard. |
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« Last Edit: April 12, 2013, 01:29:15 PM by phila_dot »
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jibberjive
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« Reply #24 on: April 12, 2013, 02:57:15 PM »
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Has anyone compared the KR hysteresis etc maps in the RS4 files to the S4? I'm curious what differences there are, if any. The knock sensor filtering is likely a little bit different, with the different pistons/compression ratio etc.
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phila_dot
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« Reply #25 on: April 12, 2013, 04:11:04 PM »
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Has anyone compared the KR hysteresis etc maps in the RS4 files to the S4? I'm curious what differences there are, if any. The knock sensor filtering is likely a little bit different, with the different pistons/compression ratio etc.
Are you talking about KRANH and KRALH? These are for defining adaptation ranges. |
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littco
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« Reply #26 on: April 13, 2013, 05:40:40 AM »
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While I am green to most of this. Isn't it all just a wash?
If I have my tune currently pulling say, -6.5(average) on all cylinders but don't feel like that is "safe" and dial back 4-5 degrees to achieve -1.5(average) on all cylinders it's still achieving the same actual timing, right? The -6.5 would be causing ignition at say 10(hypothetical) degrees BTDC and the "dialed" back -1.5 would also be 10 degrees BTDC ignition.
You might find though dialling back 1 degree will get the average down to -1.5 .. Just because you gave a cf of 6 doesn't mean you need to pull 4 degrees to get back to 2.. |
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nyet
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« Reply #27 on: April 13, 2013, 09:53:25 PM »
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Are you talking about KRANH and KRALH?
These are for defining adaptation ranges.
I think there may still be some bad information about those maps in the s4wiki. I have not gone back to correct them yet. |
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