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Author Topic: МЕ3.8.3 - tuning KFLF and KFZW for loads above 10ms  (Read 26000 times)
prj
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« Reply #15 on: May 07, 2014, 04:12:42 PM »

Yes of course your ignition timing tables will be useless.
That's why you have knock logging, headphones and dyno.

It is NOT easy to tune these ECU's to high power.
I have a few cars running 310-350hp on these ECU's since years incl. full boost control. But it took me two weeks to calibrate the first car, and I have a lot of experience with tuning Motronic.

This ECU is really the wrong one to start with. Do an ME7 conversion and make use of the knowledge on this forum, it will be MUCH easier for you than trying to do anything with M3.2x/M3.8x. Impossible without realtime emulator and proper external data logger…

The way I did it was emulator instead of 29F200 chip. Wideband data logger with inputs logging AFR, Boost, RPM, MAF voltage.
Logging via VCDS for either Boost control or Knock control.
I converted the cars to a HFM5 R32 sensor from the old HFM2, incl. rewiring for the 5V reference…
Then many many hours tuning fuelling, timing, boost control and also COLD START, it was completely broken after messing with KHFM and FGAT0…

It's a proper nightmare tuning this, especially when doing it professionally for a customer and there can not be any glitches in the software.
« Last Edit: May 07, 2014, 04:14:35 PM by prj » Logged

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eliotroyano
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« Reply #16 on: May 08, 2014, 06:07:04 AM »

I think that old Motronic Achilles heel, is it poor tunability, basically slow & poor data logging. Maybe I am nuts, but I think that it can be treated like TEMPLATE allowing it work with 10ms+ loads. After that it can be adjusted for proper tuning.
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overspeed
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« Reply #17 on: May 08, 2014, 10:03:49 AM »

You shall try tuning an M2.10.4 to see what is an slow and poor unit lol !
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prj
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« Reply #18 on: May 09, 2014, 12:15:16 AM »

I tune M2.1, M2.3 etc.
For those I wrote custom firmware with own logging protocol.

I have 15hz data logging with 30 variables.

Never bothered to learn the 80C196 chip's assembly though, because there is only one tuneable engine with this ECU and it's 1.8T.
Not worth it investing the time.
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Dropout
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« Reply #19 on: August 05, 2014, 01:28:04 AM »

Bigger MAF + MLHFM =>  Right g/s readings, but load will increase in proportion (and shall be more than 12,75ms limit)
Bigger MAF + MLHFM + KHFM => Rigth g/s readings and load will be lowered again to "normal" levels (10ms axis)
The logic can bem simplified to
  Ld = K x MAF/KHFM
If you raise MAF value (in g/s by using rigth MLHFM) then Ld value will raise it too... and shall touch 12,75ms/umdr
to keep Ld in "sane" values you raise KHFM in same proportion...

Must of missed this post. Why would load increase in the first case if the g/s readings match after scaling ? I've scaled the MAF and the g/s readings are very close when I logged them before/after, load seems to much also (without changing KHFM).

Here is a graph of g/s before/after, I'll see if I can dig up a graph of the load before/after .

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overspeed
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« Reply #20 on: August 06, 2014, 11:30:20 AM »

let´s resume it:

The goal is to lower load to avoid reaching 12,75ms:

1- If you change MAF for a big one:
   The g/s readings will be underscaled => load will be smaller proportionally in area increase

2- If you want to keep g/s correct:
    Change MLHFM + g/s will be Ok again, but load will increase to same load before MAF changed

3- If you want to lower load and keep g/s readings rigth:
     Change MLHFM and KHFM  to compensate it.


(By the way, get an Golf done by another guy last week that reach 12,75ms/umdr in 3.500~3.800RPM but worked 100% Ok)
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Dropout
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« Reply #21 on: August 08, 2014, 12:41:02 AM »

Exactly, so to recap - if say you are hitting the MAF limit but not the load limit you can just modify MLHFM (after installing a bigger MAF) but if you are also hitting load limit then KHFM has to be changed also in order to bring load down below the 12.75 limit. Important thing to know is that after modifying KHFM one must modify the spark/fuel tables .

I've also seen 2-3 cars hitting the load limit but running fine,  on those cars KFLUL.0/KFLUL2.0/KFMLDMX ect. where maxed out, which in my opinion is not a good way to tune them.
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eliotroyano
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« Reply #22 on: August 27, 2015, 05:17:03 AM »

Looking at all this maps I get why some tuners just set the protection maps to FF and tune the ignition and fuel (rows at 10ms) to the max boost/load  Roll Eyes .

Friends sorry to take this thread to life again, but I was investigating some info and have a doubt, anyone knows which are the protection maps that was commented here?
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Dropout
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« Reply #23 on: September 07, 2015, 01:09:28 PM »

From memory -> KFMLDMX ( airflow kg/h) and LDSMXN (load)
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eliotroyano
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« Reply #24 on: September 08, 2015, 08:37:37 AM »

From memory -> KFMLDMX ( airflow kg/h) and LDSMXN (load)

Really thanks, I have saw it but do you know what changes in ECU or Engine behavior are produced when we reach these values Huh Huh Huh
Heavy AFR enrichment? timing retard?
« Last Edit: September 08, 2015, 08:41:28 AM by eliotroyano » Logged
overspeed
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« Reply #25 on: September 10, 2015, 07:14:29 AM »

From memory too

KFDLUL will cut N75% to 5%
KFMLDMX will enrich (alpha-n)
LDSMXN just lower you N75% (Don´t think it´s a limiter at all)
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eliotroyano
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« Reply #26 on: September 10, 2015, 07:52:39 AM »

From memory too
KFDLUL will cut N75% to 5%
KFMLDMX will enrich (alpha-n)
LDSMXN just lower you N75% (Don´t think it´s a limiter at all)

Thanks a lot as usual Junior...... I will look at it.
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Dropout
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« Reply #27 on: September 15, 2015, 02:36:54 AM »

LDSMXN just lower you N75% (Don´t think it´s a limiter at all)

As I understand it LDSMXN is maximum permitted load, so yes it's a limiter for the max load before the boost is cut i.e. N75 duty is lowered.

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overspeed
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« Reply #28 on: September 15, 2015, 07:39:32 AM »

for MY undestanding of this:

KFDLUL is a limiter=> above this limit ECU will cut N75 to 5%
KFMLDMX is a limiter => above this ECU will understand MAF is defective and use alpha-n

For this reason I don´t call LDSMXN a limiter, it is more a threshold.
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prj
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« Reply #29 on: September 15, 2015, 08:39:48 AM »

LDSMXN is target filling limit.
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