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Author Topic: MED17 Boost Control (onset)  (Read 29239 times)
316LV
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« Reply #30 on: January 26, 2018, 04:20:55 PM »

Rodney King once asked "Can we all get along?".  Well sorry Rodney, apparently not on Nefmoto  Grin

I kid but I don't want to see Nye hit anyone with the ban hammer. Maybe time to agree to disagree and move on. Just a suggestion. Feel free to tell me to go fornicate with myself though.



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carlhook
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« Reply #31 on: December 04, 2022, 03:38:52 PM »

Hi guys,

I'm looking over boostcontrol on MED17.5 (2.0TSI). as I have a classic problem I guess.

When asking for boost say 1.3bar relative , I do get that boost BUT, at boost onset, I get N75 correction (from 96% down to around 75%) at 0.8bar relative (this is the stock boost level, so it looks like it activates the Proportional part of the PID control, I guess) then it corrects back to 96% and lets me go to 1.3 bar, the boost control is fine once it is close to target. This feels like a hesitation of the car.

Is there anyone who could help identify why this happens, why the N75 doesn't wait till closer to 1.3 to "activate" the PID or is my problem something else ?

I know people use tricks like building boost gradually in order to overcome this or tune the N75 limiter map to around 75-80% in the lower rpm's so you wouldn't feel this, or just kill the P-term in the lower rpm region to reduce the effect, but i'm looking to understand why this happens, which map(s) is (are) responsible.

Thanks for any help.

Did you ever figure this one out, Im having a similar problem with my car, I think.
Can you share your map pack or ori/mod to compare?

I have cczb with med17.5 and a patched DCWG file, but I think my WG I-part maps are wrongly defined.
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quattro85
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« Reply #32 on: December 05, 2022, 02:00:25 AM »

I'm not 100% sure about this, but I think on boost onset duty cycle of N75 is brought to 96% not by boost pre-control algorithm, but with D part of the PID.
It depends on boost gradient and prediction time to calculate when boost will go above desired. As soon as this event occur it will pull out this D part.

I don't think it have something in common with stock boost level - just coincidence.
« Last Edit: December 05, 2022, 04:30:25 AM by quattro85 » Logged
prj
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« Reply #33 on: December 05, 2022, 03:47:09 AM »

Question is answered instantly by using proper logging and looking at FR.
Then you can see directly what affects what.

For example on S18 there are three different boost controllers with different strategies.
Without logging impossible to tell when what is active.

Not the case on this ECU (there are some MED17 with 2 different controllers), but still, if you don't have correct logging, it's very difficult to get anywhere, because you simply don't see what is going on.
So you can change a million maps a million times, or you can just log the correct parameters and get there in 2-3 changes.
« Last Edit: December 05, 2022, 03:51:15 AM by prj » Logged

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carlhook
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« Reply #34 on: December 05, 2022, 05:16:11 AM »

Question is answered instantly by using proper logging and looking at FR.
Then you can see directly what affects what.

For example on S18 there are three different boost controllers with different strategies.
Without logging impossible to tell when what is active.

Not the case on this ECU (there are some MED17 with 2 different controllers), but still, if you don't have correct logging, it's very difficult to get anywhere, because you simply don't see what is going on.
So you can change a million maps a million times, or you can just log the correct parameters and get there in 2-3 changes.


Darn, I was looking for a simpler fix/ solution I can pay for without jumping in the FR as I really do not want to. I have no aspirations to tune these ECU's, just messing with my own car.

What I get it a oscillation in boost on my Stage 1 file with stock PID and Patched KFTVLDST disabled.



So I bought your VehiCAL, and it looks like I need the Advanced Protocols + patch the ECU to be able to log?
Is there a cheat sheet of parameters to log for specific issues?
« Last Edit: December 05, 2022, 05:21:15 AM by carlhook » Logged
prj
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« Reply #35 on: December 05, 2022, 08:21:50 AM »

So I bought your VehiCAL, and it looks like I need the Advanced Protocols + patch the ECU to be able to log?
Probably, but the right place for those questions is support e-mail, not this forum.
Quote
Is there a cheat sheet of parameters to log for specific issues?
No, you are going to have to learn.
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fknbrkn
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mk4 1.8T AUM


« Reply #36 on: February 22, 2024, 04:49:02 AM »

What about using CWAGTV = 4 and KFWGV as precontrol?
Only thing here confuses me - using rlsol as the axis, what if i patch it to plsol ?
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prj
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« Reply #37 on: February 22, 2024, 06:46:15 AM »

What about using CWAGTV = 4 and KFWGV as precontrol?
Only thing here confuses me - using rlsol as the axis, what if i patch it to plsol ?

You can do that.
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