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Author Topic: throttle not following rlsol_w  (Read 4130 times)
lgtmelo
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« on: March 29, 2024, 02:20:09 PM »

hi, please find attached the corresponding log in case checking it is necessary.

can someone point me to that could possibly limit the throttle opening other than KFWDKSMX (already maxed) and KLRLNMXN has more than enough load? (pic attached)

it can be seen from log that misopl1, and therefore, rlsol increases but throttle doesnt follow, up until the point where rl_w goes up regardless of throttle (because supercharger), so then throttle decides to open up. what else could i log?

*edit: car is a b8 s5 4.2, med9.1.1
« Last Edit: March 29, 2024, 04:26:21 PM by lgtmelo » Logged
lgtmelo
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« Reply #1 on: March 30, 2024, 06:58:21 AM »

checked WDKUGDN just for peace of mind, and it seems i am below the limits so not it.
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prj
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« Reply #2 on: March 30, 2024, 07:02:15 AM »

WDKUGDN is not a limiter.
Also, your ECU can not see pressure or take it in account in any way, so the entire throttle control is fucked, because it's using pu_w as the input.
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lgtmelo
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« Reply #3 on: March 30, 2024, 07:33:24 AM »

WDKUGDN is not a limiter.
Also, your ECU can not see pressure or take it in account in any way, so the entire throttle control is fucked, because it's using pu_w as the input.

i understand ecu cant see pressure, but why isnt rlsol being taken into consideration in this scenario? what limiter am i missing
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lgtmelo
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« Reply #4 on: March 30, 2024, 08:16:27 AM »

looks not to be kfpzu as well
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lgtmelo
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« Reply #5 on: March 30, 2024, 01:43:14 PM »

if it helps visualize:
« Last Edit: March 30, 2024, 01:44:57 PM by lgtmelo » Logged
prj
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« Reply #6 on: March 30, 2024, 03:50:45 PM »

You will never have a good solution unless you have a pre-throttle pressure sensor (or simulated sensor) that gets fed into the calculations in code.
You were warned, you did not listen. Now deal with it.
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lgtmelo
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« Reply #7 on: March 30, 2024, 03:52:41 PM »

You will never have a good solution unless you have a pre-throttle pressure sensor (or simulated sensor) that gets fed into the calculations in code.
You were warned, you did not listen. Now deal with it.

my question here isnt even about something happening under boost, im just trying to figure out why my TB wont open according to my load request
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lgtmelo
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« Reply #8 on: March 30, 2024, 03:57:54 PM »

MKBRMXWP, KFMDBGRG, KFMDBGRK, MIVMXPNGE, MIVMXNIVE, MDGAT, KFWDKSMX, all maxed from factory.

KFPZU has limits over what im seeing so not it.
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prj
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« Reply #9 on: March 31, 2024, 02:48:04 AM »

my question here isnt even about something happening under boost, im just trying to figure out why my TB wont open according to my load request
Because it calculates the flow over throttle plate without taking pressure into account and thinks that the throttle opening is enough that it gives for your load request. The supercharger is always producing boost, even if your manifold pressure is below atmospheric. How much the throttle sees of that really depends how it's set up and when the recirculation valve opens.
You need a dyno and then move the throttle to each operating point and calculate the actual airmass (baking the supercharger boost into it), then populate the throttle map and inverse of it.

Setting all the maps to eleven is not going to do jack shit, better get really cosy with FUEDK.

Or you need to measure pre-throttle pressure and multiply the pre-throttle flow like with SY_TURBO...
« Last Edit: March 31, 2024, 02:53:36 AM by prj » Logged

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lgtmelo
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« Reply #10 on: March 31, 2024, 04:45:31 AM »

Because it calculates the flow over throttle plate without taking pressure into account and thinks that the throttle opening is enough that it gives for your load request. The supercharger is always producing boost, even if your manifold pressure is below atmospheric. How much the throttle sees of that really depends how it's set up and when the recirculation valve opens.

exacly! and at this point, the DV isnt allowing any pressure into the TB, its working as NA. this is why i dont undertand, the throttle map in this point shouldnt change.
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prj
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« Reply #11 on: March 31, 2024, 04:57:57 AM »

exacly! and at this point, the DV isnt allowing any pressure into the TB, its working as NA. this is why i dont undertand, the throttle map in this point shouldnt change.

100 load is around atmospheric pressure, unless you scaled stuff to hell.
Pretty sure any kind of vacuum operated DV is closed at that point.

Anyway the answer is correct logging and understanding of FUEDK, you are logging like 6 vars, how do you expect to get anywhere?
Also, get a decent cable, your sample rate with 6 vars is abysmal...
« Last Edit: March 31, 2024, 05:00:26 AM by prj » Logged

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lgtmelo
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« Reply #12 on: March 31, 2024, 05:04:56 AM »

100 load is around atmospheric pressure, unless you scaled stuff to hell.
Pretty sure any kind of vacuum operated DV is closed at that point.

excellent point! so theres gotta be something going to TB even with the dv closed! thanks for this insight!

*edit: i meant dv open
« Last Edit: March 31, 2024, 05:07:37 AM by lgtmelo » Logged
lgtmelo
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« Reply #13 on: March 31, 2024, 06:45:31 AM »

so from FR, X-axis in KFMSNWDKVP is wdkbab_w, which is the minimum between wdkba_w and wdkugd_w (hence why i considered WDKUGDN as a possible limiter previously).
edit: attached is the FR portion that shows it. it depends on B_pugd (Bedingung: Druckverh¨ altnis pspvdkds_w > 0.95), so WDKUGDN would not be considered in this part throttle scenario.

regardless, this is what I have at the moment for KFMSNWDKVP:


so my understanding is that for a max of 28% TB, flow can go up to 601kg/h, which explains why at 380 flow it wont exceed the 26% at wdk1 i logged. is this the correct interpretation? meaning i should REDUCE flow limit to make opening further a possibility here.

same interpretation for its inverse, KFWDKMSNVP - 28% TB opening "works" for up to 601kg/h. need to increase TB angle here so that it will open further:
« Last Edit: March 31, 2024, 06:57:53 AM by lgtmelo » Logged
Bische
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WWW
« Reply #14 on: March 31, 2024, 01:47:00 PM »

I got contacted for this particular tuning scenario, and it is indeed a pressure conflict issue as PRJ has already pointed out.

It can be hackjob tuned around, make it run somewhat "good" - but that's nothing I would participate in, nor give pointer towards..


To have such setup tuned 100%, it needs for additional pressure sensor installed + custom code Smiley
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