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Author Topic: LEAN BURN : Target Lambda Constant  (Read 22347 times)
hipeka
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« Reply #15 on: November 18, 2012, 03:05:58 PM »

I run it this way full time on both my cars. But truthfully, I noticed more more from disabling kat heating and tuning LAMFA. The lead burn can gain you 10% better mpg but only for the time you're in that driving mode (cruise) where you're already burning a lot less that any other mode (barring overrun). Disabling kat heating (SAI) and tuning LAMFA so that ECU doesn't go pig rich every time the gas pedal even thinks you're about to press it more, will gain you more in mpg than lean burn. That's just my experience.

What is proper way to edit lamfa? Is it modifying axis data so that rich areas are in somewhere near 98-100% request or just put higher values on the last fields (in those which are allready on rich side from factory). And then make fueling depending actual load not just requested?
I have allready disable sai and katheating ,or att least i think so. Can you tell how to this also proper way? Cwkonabg maybe?

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rajivc666
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« Reply #16 on: November 18, 2012, 05:55:40 PM »

Also zeroing out kfmres and leaving kfmresk stock helps if you leave the car in neutral (without pressing clutch) while idling in traffic lights. One thing I have noticed after disabling cat and kfmres  is that it takes some  time for the car to come to operating temperature and the idle fluctuates a bit.
Also I am loosing coolant , can it be related. Huh
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jibberjive
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« Reply #17 on: November 19, 2012, 11:22:42 PM »

So, if I understood right regarding the narrowband cars, phila_dot's post #8 is basically the same method using USR that Julex posted about, but modifying those other 3 constants makes it so that the car's not fighting fuel trims.  Correct?  Anybody experimented with that any more since?
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lezsi
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« Reply #18 on: February 26, 2013, 10:56:24 AM »

Can anybody confirm that the constant to change in a HN ori
(like this: http://nefariousmotorsports.com/forum/index.php?topic=286.msg1659;topicseen#msg1659
is at 0x67944  ?

Thanks!
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lezsi
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« Reply #19 on: March 05, 2013, 05:39:14 AM »

... confirmed: Now my lambda target is always at 1.086.

Problems I've found so far:
- ignores LAMFA and KFLF enrichments (where I tried to set back to 1.00 smoothly) on lean areas. I get target 1.086 all time when it supposed to be 1 originally. I only see richer target at high loads (>100) sometimes, probably when BTS kicks in.
- lambda control is massively negative. sometimes it hangs on the -25% limit and cannot lean to target lambda. Don't know what other fueling tables need to be changed?
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lezsi
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« Reply #20 on: March 08, 2013, 08:31:16 AM »

Little progress here, I was able to enrich through LAMFA with a small DLAMFAW value, but only for LAMFA < 1 values.

I guess the lamfa_w path is maximized to 1.00 from a different 1.0 constant, hence no correction higher than 0.99 possible here.

It would be nice to set some smooth fading from 1.1 -> 1.0 through the LAMFA (or similar table).

Anyone succeeded with it?
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jibberjive
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« Reply #21 on: March 08, 2013, 10:52:00 AM »

- lambda control is massively negative. sometimes it hangs on the -25% limit and cannot lean to target lambda. Don't know what other fueling tables need to be changed?

Did you change LAMBDIAG, LREBRI, and LREBLE all to desired target lambda, like phila_dot mentions in post #8?  http://nefariousmotorsports.com/forum/index.php?topic=2515.msg24531#msg24531
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lezsi
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« Reply #22 on: March 08, 2013, 11:41:05 AM »

Did you change LAMBDIAG, LREBRI, and LREBLE all to desired target lambda, like phila_dot mentions in post #8?  http://nefariousmotorsports.com/forum/index.php?topic=2515.msg24531#msg24531

Only LAMBDIAG.
I couldn't locate the other two, and not sure they're even exist in a wideband car.
If my understanding is right, those two supposed to limit the LAMBDIAG value, and not related to trims(?). 

For limiting I've found LAMLRAMX only and that was around 1.09 already
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jibberjive
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« Reply #23 on: March 08, 2013, 11:52:22 AM »

I didn't know your car was a wideband car, and I haven't delved into the FR yet regarding those other variables to have a full knowledge, but just going off of what phila_dot said in that post, it seems like those are the only changes necessary to not be fighting the trims on a narrowband car.
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lezsi
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« Reply #24 on: March 11, 2013, 08:22:25 AM »

Sorry, I didn't emphasize it's a wideband.
Yet to see when LTFT values settle for long term use, but my first impression was that I need to set other constants too. 

I hope others will chime in with wideband experience.
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julex
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« Reply #25 on: March 12, 2013, 07:59:49 AM »

I'd ran lean lambda on my 7.1 a while ago by cahnging USR, if you search forums you will see the thread. Look at LALIUS to give you idea about V to Lambda scaling of O2 sensor.

Caveats:

Narrowband can only accurately measure a very narrow AFRs accurately, we are talking like 0.05 lambda either way.
My engine doesn't like anything over 14.7. It starts bogging down at 15.5 pretty significantly so I saw no point in running higher than stock lambda.
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lezsi
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« Reply #26 on: March 13, 2013, 08:19:27 AM »

To my best understanding of the german 7.5 FR,  two-point lambda control with USR is narrowband-only, I don't have any practice with that.

My car runs fine around lambda ~1.1, even at 750rpm idle. 
I guess the small stock injectors, larger plug gaps and TSI coils help here Smiley

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kaross
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« Reply #27 on: July 01, 2013, 03:01:06 PM »

I am also struggling to get narrowband ECU run leaner than 1.
At least 1.08-1.1 lambda.
I have read so much but can't get real answer on my question. Is it possible? For economy.
We can gain good economy running around 1,05-1,1.
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joshuafarwel
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« Reply #28 on: October 16, 2021, 05:59:38 PM »

Only LAMBDIAG.
I couldn't locate the other two, and not sure they're even exist in a wideband car.
If my understanding is right, those two supposed to limit the LAMBDIAG value, and not related to trims(?).  

For limiting I've found LAMLRAMX only and that was around 1.09 already
For kflbts fueling lambda is probably limited by
LATRO - Upper limit lambda target for exhaust gas temperature control
018ch ecu - 0X1D11E (16BIT LOHI)
offset: x*0.000244140625

latro doesnt seem to exist in 518al





« Last Edit: December 28, 2022, 08:48:08 PM by joshuafarwel » Logged
Dejw0089
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« Reply #29 on: January 19, 2022, 11:48:15 AM »

Can anyone confirm my finded adress please?
0x65C62?
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