damianalex
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A4 B7 1.8T 8E0909518AQ 0020
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« on: December 11, 2024, 02:13:27 PM »
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Hi,
A4 B7 BFB 1.8T, hardware modification: hybrid K03 turbine, FMIC, 430cc injectors, metal tip, 200cpsi cat. Air filter and maf are stock.
I've already made a lot of remaping to tune my car equipped with 8E0909518AQ 0020 ecu.
IOP/IRL taken from BAM and rescaled all other maps to changed rl_w axis (my ecu was scaled only to 145 load)
I'm running "feed forward" control for boost controler described at forum.
But I do NOT touch antyhing related to maf.
What is my problem? S4 wiki says:"Another good MLFHFM sanity check is to log ps_w vs actual boost at WOT - ps_w should generally be slightly below actual boost"
As you can see in my log ps_w is lot higher than pvdks_w and because of that rl_w is higher than rlsol_w. (I checked and there is no leakage at inlet)
It is normal, or should I change something?
Now at WOT I feel something like torqe intervention, but I can't prove it, because i don't have all variables in ME7logger for ME7.5.
Thanks for answers.
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prj
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« Reply #1 on: December 11, 2024, 03:31:19 PM »
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ps_w is modeled pressure from VE model.
Of course it's completely wrong when you changed turbo and exhaust.
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damianalex
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A4 B7 1.8T 8E0909518AQ 0020
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« Reply #2 on: December 12, 2024, 12:00:50 AM »
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I found old topic with similar problem I guess... http://nefariousmotorsports.com/forum/index.php?topic=13929Your VE model (pressure to load conversion) is not right because ECU is requesting too much boost to reach target load.
VE model is adjusted by:
KFURL - base
KFPBRK/KFPBRKNW - multiplicative correction
KFPRG - additive correction
Which one to change I can't tell you based on the data you have - you need to check on part throttle also how it is behaving.
If you have the problem in the entire range, then KFURL will help, if it's only on high boost then KFPBRK/NW should be changed at higher load.
So I'll try make logs covering wide range of load and with that I will adjust maps mentioned above. Thanks a lot prj. |
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prj
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« Reply #3 on: December 12, 2024, 03:13:17 AM »
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Before adjusting pressure test the complete intake from turbo inlet.
If you have a small leak in something connected to the manifold it will also show up in a similar way.
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nyet
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« Reply #4 on: December 12, 2024, 10:24:57 AM »
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ps_w is modeled pressure from VE model.
Of course it's completely wrong when you changed turbo and exhaust.
Is that enough to account for the difference? |
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ME7.1 tuning guideECUx PlotME7Sum checksumTrim heatmap toolPlease do not ask me for tunes. I'm here to help people make their own. Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
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prj
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« Reply #5 on: December 12, 2024, 02:11:05 PM »
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Is that enough to account for the difference? The biggest difference is the turbo hotside/turbine being bigger. That affects VE in a massive way at higher boost levels. At lower boost the difference is very small, but as you go higher it starts to become larger and larger, as the OEM hotside/turbine wheel would be creating massive backpressure at those levels, that just isn't there with the upgraded turbo. But as I wrote before, if there's a small boost leak it'll show up the same way. |
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damianalex
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A4 B7 1.8T 8E0909518AQ 0020
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« Reply #6 on: December 12, 2024, 02:59:10 PM »
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I've looked through my logs and I can confirm that difference is only on high load, so as usually prj has right  I was rebuilding my engine this year and after that I checked for leaks, but to be sure I will do double check before adjusting VE model. |
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damianalex
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A4 B7 1.8T 8E0909518AQ 0020
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« Reply #7 on: December 19, 2024, 01:19:02 AM »
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After a few run I've adjusted KFPBRK and KFPBRKNW (maybe need small correction at 5000rpm). So now it looks like this. (I know that there is a desire boost dip around 3000rpm, I will correct this at next writing file).
As you can see ps_w is little lower than actual boost, BUT still something is wrong.
When spool up near 2500-3000rpm I still can feel that car is jerking. It getting worse with VVT on. With VVT off problem is smaller.
KFDMDARO/S and one more mapp for ARMD set to 50 at 50 column.
Can please someone look at logs?
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prj
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« Reply #8 on: December 19, 2024, 02:37:46 AM »
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If with VVT off problem is smaller probably you have turbo surge, this can happen if the turbo is not correctly designed. For example too small a/r of hotside or too small turbine for compressor wheel.
Because your hybrid most likely is just larger wheels in standard housing, there is your problem. The turbine housing a/r is most likely too small.
Only thing you can do is find the surge line and limit the pressure ratio over the turbine (kfldhbn) to avoid the issue. Of course needs well tuned boost control also, so it does not overshoot.
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aef
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« Reply #9 on: December 19, 2024, 04:16:20 AM »
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Log again and dont cut your logs at the beginning or end.
start from 1500 and hold 100% throttle until redline.
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damianalex
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A4 B7 1.8T 8E0909518AQ 0020
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« Reply #10 on: December 19, 2024, 06:04:49 AM »
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My turbo is made with k04-015 parts with some modification at original housing. What I can see from the outside is that cold side inlet has enlarged diameter, but outlet to intercooler is stock. WG has tighter spring and new membrane inside. (current crank pressure is about 0.55bar. Little to much, but I don't want to change it). Turbo has fast spool, but is weaker at the top and we can see it from logs. It is possible that this is turbo surge what I feel when car is jerking. Any noise shuld I hear connected with that? Quick look in FR and I see that kfldhbn after all calculation limits rlmax_w. I'm still making small adjustments in PID controller and in my feed forward control to prevent overboost. Now is up to 100mbar at spool and after gear changing so it isn't that much (I think...  ) |
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« Last Edit: December 19, 2024, 06:24:59 AM by damianalex »
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damianalex
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A4 B7 1.8T 8E0909518AQ 0020
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« Reply #11 on: December 19, 2024, 06:17:55 AM »
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Log again and dont cut your logs at the beginning or end.
start from 1500 and hold 100% throttle until redline.
I usually have full logs (from 1500-6500rpm). Problem is that I'm making them usually riding from work to home and log is about 3megabytes size and have a lot of unnecessary trash. I've cut the log with 160 req load and vvt on because there was no opportunity at the road to make from 1500 to 6500rpm. For 170 load and vvt off log is full. I can make log with 160 load and vvt on again if its needed. |
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aef
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« Reply #12 on: December 19, 2024, 07:06:03 AM »
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I just asked because log is ending at 3xxx rpm
I have seen surging on the maf line in the log. I dont think yours is surging.
regards
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damianalex
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A4 B7 1.8T 8E0909518AQ 0020
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« Reply #13 on: December 19, 2024, 02:52:30 PM »
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Coming with new info and new log.
- jerking I am talking about I can describe as adding and then suddenly go back with acceleration pedal, and than again adding etc.
- this happens not only when WOT, it happens also at part throotle (even for example 20%) while turbo spools up. Only to 3000rpm, then it is ok.
- it does not happens if turbo spool up at higher rpm. For example I am crusing at 3 gear at 3000rpm with minimal acceleration pedal and then I h the floor, the boost rise up and it is smooth.
- as I've wrote earlier I can feel it stronger when VVT is on (also at part throotle).
- the worst situtation is when engine is cold for example after 8 hours of staying, then even with minimal accelration pedal there is relatively big jerking while spool up.
- at least but not last I can say that while riding on LPG problem is very very small even with vvt on.
Any ideas?
Here is log with 170 load and VVT on.
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fknbrkn
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mk4 1.8T AUM
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« Reply #14 on: December 19, 2024, 03:21:49 PM »
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Coming with new info and new log.
- jerking I am talking about I can describe as adding and then suddenly go back with acceleration pedal, and than again adding etc.
- this happens not only when WOT, it happens also at part throotle (even for example 20%) while turbo spools up. Only to 3000rpm, then it is ok.
- it does not happens if turbo spool up at higher rpm. For example I am crusing at 3 gear at 3000rpm with minimal acceleration pedal and then I h the floor, the boost rise up and it is smooth.
- as I've wrote earlier I can feel it stronger when VVT is on (also at part throotle).
- the worst situtation is when engine is cold for example after 8 hours of staying, then even with minimal accelration pedal there is relatively big jerking while spool up.
- at least but not last I can say that while riding on LPG problem is very very small even with vvt on.
Any ideas?
Here is log with 170 load and VVT on.
read wiki about tighter wg spring |
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