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nyet
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« on: July 29, 2011, 10:38:15 AM »
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If your fueling and intake system are VERY different from stock, is there any point to sticking with the stock FKKVS and KFKHFM? Doesn't it make more sense to set them all to ones, and start fueling tweaks from there?
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s5fourdoor
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« Reply #1 on: July 29, 2011, 10:46:09 AM »
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Exactly what I was thinking about! I was thinking to do this in conjunction with the Innovative Log-works software which measures the mean and standard deviation of your Wideband AFR's. They have some two dimensional table which I believe looks at RPM vs MAP values.
Have you attempted setting these two tables to 1? Paradicisia2.7t or whatever his name is, commented on my EV14 thread. He said that his "general procedure" is to set KFKHFM to 1 and then get his KRKTE adjusted. After that he does an hour of road logging and tries to refine the KFKHFM table. He didn't say anything about FKKVS.
Also, I can't help but think that FKKVS would only come into play under serious load, if you had the ECU calibrated correctly.... I mean think about the dynamics of our cars. We have decently sized engine with two medium to large to huge turbos (depending on who you are)...
You tune a daily driver to be smooth under low-medium power conditions and then would adjust for high power running.
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nyet
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« Reply #2 on: July 29, 2011, 10:49:31 AM »
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I'm actually in the process of completely rewriting my tune for stock airbox, 85mm MAF, 60lb dekas... right now, my KFKHFM is all ones, and am THINKING about doing the same for FKKVS. I haven't decided yet if the stock FKKVS might still be applicable to my set up. Also, I'm pretty sure the stock KFKHFM is completely useless for an open air element intake, but it MIGHT be somewhat useful for a stock airbox. I have no idea really, which is why I posted  |
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« Last Edit: July 29, 2011, 12:32:11 PM by nyet »
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berTTos
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« Reply #3 on: July 29, 2011, 11:25:23 AM »
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i have to believe that the stock KFKHFM is only an appropriate match for a stock intake tract including, stock air box (without a hole), paper filter, 73mm MAF w flow straightener, K03s + stock inlets, stock DPs.
mine is set to 1s currently and i plan on dialing it in after much logging to identify rpm/load areas that indicate a need for signal correction (all it takes is time, right?). my current tune using Tony's 85mm scale w/ KFKHFM set to 1 is working beautifully from 75* - 105* ambient. i'm sure there are some spots that could use correction but nothing that's upsetting load calcs/fueling. we'll see if it needs tweaking in cold weather.
as far as FKKVS - stock table values do not contain any variance across data points so setting the table to 1 would be equivalent to slightly adjusting KRKTE - right? i have no plans to alter this table.
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s5fourdoor
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« Reply #4 on: July 29, 2011, 12:10:38 PM »
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Regarding changing the values for FKKVS from 1.02 to 1.00, I completely agree.
Honestly this table seems like a kluge with standard fueling methods. Now if you toss in NOS or sprayed Water/Meth into the picture, I could definitely see a rationale for wanting a fuel-correction. Agreed? Then again, most external controller's have their own gain controls, specifically because the engineer designing the product doesn't expect the user to have an ability to do OEM-based Fuel Supply Corrections...
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NOTORIOUS VR
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« Reply #5 on: July 29, 2011, 01:14:56 PM »
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I agree with what has been said here as well...
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nyet
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« Reply #6 on: July 29, 2011, 04:25:18 PM »
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All i can think of is that Klaus The Engineer derived the stock KRKTE mathematically, then somebody later discovered it was off by 2%. Instead of just adjusting KRKTE (which would have been sacrilege, since it was derived from injector flow rate and FPR data, no doubt), somebody hacked FKKVS by 2%.
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berTTos
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« Reply #7 on: July 29, 2011, 06:42:22 PM »
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All i can think of is that Klaus The Engineer derived the stock KRKTE mathematically, then somebody later discovered it was off by 2%. Instead of just adjusting KRKTE (which would have been sacrilege, since it was derived from injector flow rate and FPR data, no doubt), somebody hacked FKKVS by 2%.
no doubt he was shot at dawn for his mistake  |
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paracaidista2.7T
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« Reply #8 on: July 30, 2011, 04:50:36 AM »
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I have done it this way for some time. I set all to 1, and fine tune from there. Initially, I was having inconsistencies in fueling and tried this to correct. Funny thing is, I had intended to ask Nyet this very question for about a year or so.
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silentbob
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« Reply #9 on: July 30, 2011, 08:54:13 AM »
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All i can think of is that Klaus The Engineer derived the stock KRKTE mathematically, then somebody later discovered it was off by 2%. Instead of just adjusting KRKTE (which would have been sacrilege, since it was derived from injector flow rate and FPR data, no doubt), somebody hacked FKKVS by 2%.
That is excatly how the calibration process works at OEMs   |
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Bische
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« Reply #10 on: August 15, 2012, 11:45:45 AM »
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Im in the process of fine tuning my fueling and are focusing on the KFKHFM/FKKVS maps, and wanted to discuss one idea I have regarding tuning these maps. I have changed just about everything in my setup, intake/MAF/turbo/IC/injectors/exhaust, and I have nothing sane left to tune against.
Then my idea was to tune the airflow correction KFKHFM against MAP pressure. Requested boost is calculated from load, which is an cylinder filling/airflow request. And boost pressure is a direct product of airflow, right? Here is what I did:
I did set up a little calculation sheet where lde=0 did rlsol_w/rl_w to get the correction factor, ran a 1hour/50hz log through and averaged, then plot out on in an authentic KFKHFM map. Hand edited it some and applied it to my KFKHFM, but man did it backfire!
This didnt work, I was under the impression that we wanted to have the rl_w to follow rlsol_w closely when lde=0? Or am I way over thinking this?
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nyet
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« Reply #11 on: August 15, 2012, 01:17:17 PM »
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This didnt work, I was under the impression that we wanted to have the rl_w to follow rlsol_w closely when lde=0? Or am I way over thinking this?
Yea, if you do that, you'll get torque intervention up the yin yang. ME7 really really wants rl_w to be strictly less than rlsol_w |
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Bische
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« Reply #12 on: August 15, 2012, 07:20:27 PM »
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Yea, if you do that, you'll get torque intervention up the yin yang. ME7 really really wants rl_w to be strictly less than rlsol_w
Alright, so roughly rl_w<rlsol_w induces intervention. I have been experiencing more or less intervention v1 since day one, and my rl_w has always been higher than requested with like 5-10% sometimes up to 20%. Back to the drawing board, I have tried to correct KFKHFM using my wideband STFT's in the past(with success regarding mixture control), but I did end up scrapping that since there is a whole lot more to consider between rl_w to ti_b1 and I was thinking I must have been wrongly correcting for errors developed in that path. |
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pizzaschnitzer
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« Reply #13 on: November 25, 2016, 03:37:32 AM »
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my the translation from the funktionsrahmen helps you
KFKHFM:
In Bereichen ohne Pulsation wird der Luftmassenabgleich ¨uber das Kennfeld KFKHFM durchgef¨uhrt.
Dadurch k¨onnen HFM-Fehler, z.B. durch Problematische Einbaulage verursacht, korrigiret werden.
Bei beiden Abgleichen soll das Lambda ungef¨ahr 1.0 sein, damit der Fehler bei der Berechnung der Luftmasse ¨uber das Abgas gering
ist.
Die Restfehler ( Lambdaabweichungen von 1.0 ) werden als Gemischfehler interpretiert und sind ¨uber das Kennfeld FKKVS in %rkti
zu kompensieren.
The Areas without pulsations will be adjustet via KFKHFM, therfore you can correct adverse mountings and irflows in the intake system with it.
both alignments should sesult near Lambda 1.0 in order that the Lambda error in exhaust system is near zero.
Leaving errors will be corrected via FKKVS
so the theorie to set all to 1 is correct in case you have modified intake (open airbox, duct, anything)
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nyet
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« Reply #14 on: November 25, 2016, 01:49:09 PM »
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so the theorie to set all to 1 is correct in case you have modified intake (open airbox, duct, anything)
Stock ME7.1 KFKHFM is not all one Stock ME7.1 KFFVS is all one |
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