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Author Topic: LAMFA vs KFLF  (Read 17492 times)
Rick
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« on: October 28, 2010, 02:31:07 PM »

I understand that KFLF is the partial load fuel table, so will be used during cruise etc.

If so, what is LAMFA used for?  Is it for WOT when EGT is below the BTS threshold?  What are the axis? One is RPM, what is the other?  I presume the data is Lamba, but on a stock tune all values are set to 1, so what is the point of the table?

Rick
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hammersword
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« Reply #1 on: October 28, 2010, 04:32:17 PM »

I understand that KFLF is the partial load fuel table,
wrong. The translation name it part load, but is a pre correction map for fuel algo

so will be used during cruise etc.
at cruise you run close loop, other maps do the calculation to give you the stoich mix and lambda trims fuel to keep it 14.6 - 15
Wink

If so, what is LAMFA used for?  Is it for WOT when EGT is below the BTS threshold?  What are the axis? One is RPM, what is the other?
LAMFA is lambda demand. You request mixure, the ECU makes calculation and give it to you!
The BTS is another story and there is for component protection


 I presume the data is Lamba, but on a stock tune all values are set to 1, so what is the point of the table?
If you wanna run 14.7, set it to 1.0. If you like richer fix it!
becareful with BTS because in some situations they are activated.

Understand when BTS is activated, how EGT is calculated by ECU and what maps do that, and then you find all your answers and you will decide if you wanna work only with LAMFA, or with alternative load by BTS as sometimes Bosch like to tune!

Ciao
Fotis



« Last Edit: November 29, 2010, 06:55:04 PM by Tony@NefMoto » Logged

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Rick
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« Reply #2 on: October 29, 2010, 02:22:56 AM »

Fotis,

thank you for your input, very informative.

I am still having difficulty understanding KFLF.  Bosch run Stoich for emission reasons, for the cat to work efficently.  I will have no cat, and so would like to run around lambda 1.1 for greater fuel economy on cruise. 

Do I not need to touch KFLF?  I can just edit LAMFA so that at certain loads I enter lambda 1.1 instead of 1? 

When WOULD i edit KFLF?  I understand that BTS is activated for component protection, but when the EGT is below TABGBTS, is closed loop/LAMFA still used?  That is, on a WOT pull, if the EGT' are low does the engine run Lambda 1?  This would seem bad from power - I would like to run lambda 0.85 every time the car is under WOT, then use BTS to richen when needed.

Rick

   
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turboskipper
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« Reply #3 on: October 29, 2010, 06:03:49 AM »

You should not use KFLF, it has to do with fuel pulsations and other things. See this note from Bosch here...
Quote
The KFLF map should not be used for intervening in the mixture, because the relative air charge rl must be balanced to the engine
demand via the pulsation map KFPU. If rl is corrected by KFPU faktor fgru has to be 1.0
The two interventions vsfrk and FRKAP are multiplying interventions via application devices. FRKAP is changed by VS100 adjustment;
vsfrk by VS20 or via the serial interface. These two interventions must be set to neutral during definition after start of
production

So you should use LAMFA, LAMBTS or LAMKR. There is a good thread about LAMFA, LAMBTS and LAMKR already.

Cheers
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Rick
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« Reply #4 on: October 29, 2010, 07:37:19 AM »

turboskipper -

it seems then the map isn't very usefully named!

have you got a copy of the doc you got that info from please?

Rick
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hammersword
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« Reply #5 on: October 29, 2010, 05:42:36 PM »

there are no Part or full or idle maps on ME7 and newer Motronics!

The KFLF is that what turboskipper says. Forgot it, you will not do anything, just a lot of fuel trims.

If you like to run at 1.1 then go and change lamda controller upper and lower limit, so the lambda corrects from 1 - 1.1 and not from 0.95 - 1.05 as stock

LAMFA has RPM and KFPED values as axis!
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turboskipper
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« Reply #6 on: November 01, 2010, 07:08:26 AM »

turboskipper -

it seems then the map isn't very usefully named!

have you got a copy of the doc you got that info from please?

Rick

You need the ME7 documentation. Normally this can be found for $$$ or trade of files.
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vanrhj
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« Reply #7 on: May 24, 2022, 03:11:22 AM »

You should not use KFLF, it has to do with fuel pulsations and other things. See this note from Bosch here...
So you should use LAMFA, LAMBTS or LAMKR. There is a good thread about LAMFA, LAMBTS and LAMKR already.

Cheers

Can u maybe share the link to this thread?
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nyet
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« Reply #8 on: May 24, 2022, 01:43:53 PM »

holy necro bump lol.

Did you start with the stickies, or god forbid *my fucking sig*

https://s4wiki.com/wiki/Tuning#Fueling
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