Pages: [1]
Author Topic: Limiters, what units are used in LDRXN, LDRXNZK and KFLDHBN?  (Read 19287 times)
fredrik_a
Full Member
***

Karma: +25/-0
Offline Offline

Posts: 221


« on: December 13, 2010, 04:22:55 PM »

Hi all,

Being new to Audi I just stumbled across this site and immediately got a warm and nice feeling.  Grin
In the past I've tuned my older Volvo's (using Motronic 4.3 and 4.4) but the ME7 is all new to me and I'd like to (if it's ok with you guys) ask a few questions about my car that I have not yet found any answers for whilst using the search function.

Allright, here we go...

A week ago I got an Audi A3 1.8TQ. I've read the stock software (it's a 0261206892/06A906032BJ/360151) and started to look around.

a) Using a proper damos it's easily navigated but there are a few things that I'm not familiar with... The german description of the maps (as I do speak german) suggests that LDRXN and LDRXNZK are limiters for nominal operation and and knocking conditions, but what is the actual value in the map representing? As the map is also labled "LDR" (which usually is an abbrevation for "ladengedruck" (in german) or "boost" in english), one would guess that it represents boost levels, but the map contains figures well belo actual boost values read during driving. Not much of a limiter then? What is the unit...?

b) There is another map labled KFLDHBN, which with the german description also refers to LDR which suggests boost pressure, and at the same time it says (regarding on how the wording is interpreted in german) "altitude/height/level"-limiter. Looking in the damos, that map has a degrees Celcius scale... What is the temperature? Manifold air temp?


If anyone has any info on this I'd be so happy.


Best regards
Fredrik
Logged
setzi62
Full Member
***

Karma: +142/-0
Offline Offline

Posts: 249


« Reply #1 on: December 14, 2010, 09:47:13 AM »

LDR means boost control. The unit of LDRXN and LDRXNZK is percent (%) and
the values represent a load (to get real values, multiply with 0.0234375).
KFLDHBN has no unit, the values represent max. pressure ratios. This map should
compensate for different height levels.
The axes of this map are engine speed and intake air temperature.
Logged
Rick
Hero Member
*****

Karma: +62/-4
Offline Offline

Posts: 704


« Reply #2 on: December 14, 2010, 09:55:08 AM »

The units are engine load.  To get absolute oressure, add 30 and multiplt by 10.  For example, load of 120=120+30 *10=1500mbar, or 0.5 bar boost.

Rick
Logged
fredrik_a
Full Member
***

Karma: +25/-0
Offline Offline

Posts: 221


« Reply #3 on: December 14, 2010, 10:21:52 AM »

Thanx a lot guys. I really appreciate this!
Logged
99pwr
Full Member
***

Karma: +15/-0
Offline Offline

Posts: 85


« Reply #4 on: December 14, 2010, 01:22:46 PM »

The units are engine load.  To get absolute oressure, add 30 and multiplt by 10.  For example, load of 120=120+30 *10=1500mbar, or 0.5 bar boost.

Rick

Or can be used 0.234375 factor and 300 offset.
Logged
fredrik_a
Full Member
***

Karma: +25/-0
Offline Offline

Posts: 221


« Reply #5 on: December 14, 2010, 05:07:41 PM »

Thanks for the swift feedback, it's really appreciated. Stock file has now been modified (just a few maps) and flashed in the ECU. After a testspin (as I have no clear picture of what primarily KFMIRL and KFMIOP means in terms of actual boost pressures) it was evident though that stock boost of about 0.6 bar has now become 1.15-1.20 bar in the modified file. I see a little swift overshoot in the boost pressure of about 0.15 bars that needs to be adressed. As the KFLDRL seems to be set all the way up to 95% for the final row, I will try to reduce this somewhat as the true frequency of the valve isn't near that during "normal operation" at 1.1 bar so to speak... Perhaps I'm mistaken here but at least it might be worth trying as I fail to find any D-part of the PID that can help me with predicting a coming overshoot...?

As fueling and ignition timing hasn't been altered yet I will need to confirm that mixture is decent tomorrow and that I don't have any excessive ignition retard. If so, stock ignition table needs to be adjusted for the load increase. Other than that, it seems to be working properly.
Logged
RaraK
Hero Member
*****

Karma: +58/-2
Offline Offline

Posts: 537


« Reply #6 on: December 15, 2010, 09:28:39 AM »

Thanks for the swift feedback, it's really appreciated. Stock file has now been modified (just a few maps) and flashed in the ECU. After a testspin (as I have no clear picture of what primarily KFMIRL and KFMIOP means in terms of actual boost pressures) it was evident though that stock boost of about 0.6 bar has now become 1.15-1.20 bar in the modified file. I see a little swift overshoot in the boost pressure of about 0.15 bars that needs to be adressed. As the KFLDRL seems to be set all the way up to 95% for the final row, I will try to reduce this somewhat as the true frequency of the valve isn't near that during "normal operation" at 1.1 bar so to speak... Perhaps I'm mistaken here but at least it might be worth trying as I fail to find any D-part of the PID that can help me with predicting a coming overshoot...?

As fueling and ignition timing hasn't been altered yet I will need to confirm that mixture is decent tomorrow and that I don't have any excessive ignition retard. If so, stock ignition table needs to be adjusted for the load increase. Other than that, it seems to be working properly.


I didnt really do too much with timing on my car, so make very small changes, the stock map is fairly decent on mbox s4, but dont just select the whole map and start bumping it up, you only need to modify a 1/3 of the map realistically.  I only modded the top end a bit too, my CF's are usualy 4-6 on a 4th gear pull with stock IC's

Logged
fredrik_a
Full Member
***

Karma: +25/-0
Offline Offline

Posts: 221


« Reply #7 on: December 15, 2010, 12:04:50 PM »

...so make very small changes...

The only change done now was to decrease the dc-level for the boost valve that is set to 95% in the stock file to about 87% instead and the overshoots went away. As far as I can see, spool wasn't affected by this change so it's still fast regulation but with less overshoot so it worked out OK I guess.

Having logged a bit more today revealed that ignition retard due to knock isn't active either so ignition timing seems to be fairly allright although todays weather isn't really suited for this kind of evaluation perhaps... It's -8 degrees C outside so...
« Last Edit: December 15, 2010, 12:09:36 PM by fredrik_a » Logged
ArgDub
Full Member
***

Karma: +60/-1
Offline Offline

Posts: 202


« Reply #8 on: December 22, 2010, 10:52:44 AM »

Have a look at http://s4wiki.com/wiki/Tuning, it gives a good run down on what to do to get started, once you have absorbed that you can get a copy of the me7 docs
Logged
fredrik_a
Full Member
***

Karma: +25/-0
Offline Offline

Posts: 221


« Reply #9 on: December 25, 2010, 04:14:39 PM »

Have a look at http://s4wiki.com/wiki/Tuning, it gives a good run down on what to do to get started, once you have absorbed that you can get a copy of the me7 docs

Thanks, I started reading that at the same time that I posted this thread originally :-)
Another thing that still puzzles me somewhat... KFMIRL states "basic" load if I understand things corectly, KFPED is the requested "relative" torque (0-100%) by the driver, but what does KFMIOP actually do? (I adjusted this map also and car runs fine, but perhaps that was unneccesary?) Is that map "multiplied" together with KFMIRL & KFPED for torque/boost control?
Logged
lu1227@op.pl
Newbie
*

Karma: +1/-1
Offline Offline

Posts: 9


« Reply #10 on: August 01, 2020, 11:06:39 AM »

what do i have to do to correct the torque from below???
Logged
Pages: [1]
  Print  
 
Jump to:  

Powered by SMF 1.1.21 | SMF © 2015, Simple Machines Page created in 0.026 seconds with 17 queries. (Pretty URLs adds 0s, 0q)