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Title: not reaching desired boost Post by: aef on June 06, 2022, 11:24:10 AM Hi,
after a long night of logging on my new setup i had nearly perfectly 1,6bar req and actual matching pretty good. ignition was 16degree up top. logging the same setup today on a hotter environment, same street, same slope i have 1,4bar and wastegate is not willing to do its work to reach 1,6bar like requested. In theory on a colder night i would need less boost because of a better O2 on my intake. On a hotter day i would need more boost to reach the same power because of a lower O2 saturation. What could be the "problem" besides my limited knowledge. Is it related to tans or tmot? how is me7 knowing the air density or O2 content? Title: Re: not reaching desired boost Post by: nyet on June 06, 2022, 11:53:15 AM Maybe not the problem, but i've seen N75s behave differently depending on underhood temps, and sometimes other variations.
Re: hot days, load->boost conversion variance: https://s4wiki.com/wiki/Tuning#IAT_effect_on_specified_load_and_requested_boost Quote However, if you are running a lot of boost, and always want maximum performance, there is no point in increasing boost when it is hot, let alone reducing boost when it is cold. Also, as IATs rise, even with a perfectly flat KFTARX and LDIATA (see below), you will see more requested boost because the ECU knows that a higher P/R is required for a given cylinder fill (through the ftbr correction factor). To compensate, you may want to taper KFTARX across the board as IATs rise to keep your requested boost sane. Make sure LDIATA reflects those changes properly. Alternately, in theory, you should be able to find values for FWFTBRTA such that it cancels out the fixed IAT ftbr correction. In particular, be aware that the maximum requested boost is slightly above the maximum MAP reading. Readers who understand PIDs should recognize that really bad things happen when the measured output cannot reach the setpoint. If you have tuned your PID to really only work with a single set of req boost curves, if the req boost changes, it may not behave well. This is a pretty big problem, and hard to solve w/o taking another look at your PID tuning approach; alternately, just try to make boost request look the same across a variety of IATs. BTW you'll see the same problem with elevation variance. Title: Re: not reaching desired boost Post by: BlackT on June 06, 2022, 12:36:26 PM Get a N75 from TFSI
Those from 1.8T and 2.7T change as moon change Title: Re: not reaching desired boost Post by: aef on June 06, 2022, 02:31:24 PM Hi,
N75 is a brand new Pierburg 7.00470.07.0 The problem is not the output or the behaviour of my N75. My problem is the output of the ecu to the N75. My KFTARX is chanced to 1 up to 80 degree celsius. Only thing i did the other night was to lower my ldrxn up to 4000. Maybe i have to up it to make the gap between boost desired and boost actual greater? please ignore lambda and egt in my logs. why is todays wgdc that low when going wot? Title: Re: not reaching desired boost Post by: nyet on June 06, 2022, 02:54:06 PM Looks like IMAX trim action
Title: Re: not reaching desired boost Post by: justinvw2646 on June 06, 2022, 06:07:39 PM I have gotten more consistent boost pressure from mine by moving LDRXN up and out of the way and using KFLDHBN instead. I know the ideal way would be to use both, but I was concerned with over spinning the turbo on hot days trying to meet request. Maybe worth a try?
Title: Re: not reaching desired boost Post by: nyet on June 06, 2022, 08:58:17 PM I have gotten more consistent boost pressure from mine by moving LDRXN up and out of the way and using KFLDHBN instead. I know the ideal way would be to use both, but I was concerned with over spinning the turbo on hot days trying to meet request. Maybe worth a try? His IMAX is moving, not his boost req Title: Re: not reaching desired boost Post by: fknbrkn on June 06, 2022, 10:27:23 PM Ldiata? But its pretty conservative in stock so..
Title: Re: not reaching desired boost Post by: nyet on June 06, 2022, 10:52:30 PM No, its pretty clear his imax is changing between the two runs, which isn't boost req related
Title: Re: not reaching desired boost Post by: fknbrkn on June 06, 2022, 11:40:54 PM Iirc ldiata is the iat based additive to imax
Title: Re: not reaching desired boost Post by: BlackT on June 06, 2022, 11:48:55 PM Show your IMX table
Title: Re: not reaching desired boost Post by: aef on June 06, 2022, 11:59:37 PM I walked down the pre control road...
this was all done in the same night where the first log was created. Title: Re: not reaching desired boost Post by: BlackT on June 07, 2022, 12:15:03 AM Can you show LDIATA map
Also log STLDIA 1 2 3 4 Title: Re: not reaching desired boost Post by: aef on June 07, 2022, 05:26:09 AM my LDEIAO, LDEIAP, LDEIAPS and LDEIAU is chanced a bit from stock
could be related to 5120hack, i have to check my old revisions when i changed this and why LDEIAO from 40 to 20 LDEIAP from -20 to 1270 LDEIAPS from 50 to 20 LDEIAU from -60 to 1270 ::) LDIATA and STLDIA is stock. What do you want me to log? I have nothing like STDIA in my logger config(s) thx Title: Re: not reaching desired boost Post by: BlackT on June 07, 2022, 05:40:07 AM I mean
ldimxa_0-5 Also Ldimx_w And Ldimn_w Title: Re: not reaching desired boost Post by: nyet on June 07, 2022, 09:31:56 AM Looks like IMAX trim action Please read again :P ldimxa ... Title: Re: not reaching desired boost Post by: aef on June 07, 2022, 01:12:16 PM Attached you will find my 1st and 5th log from today. Environment was like 17degree celsius. I parket the car to let it heat soak to reproduce the problem.
As you can see, first log was wonderful, 95% 1,6bar like requested. Last log was 85% highest and underboosting. Unfortunatelly i am unable to interpret the newly logged vars. I will have to read alot about this. edit: https://s4wiki.com/wiki/Tuning#I-Regulation_adaptation Title: Re: not reaching desired boost Post by: nyet on June 07, 2022, 03:40:55 PM For some reason you have a whole lot of imx trim activity... not sure why they're so crazy negative, unless there are times when you are crazy overboosting
Title: Re: not reaching desired boost Post by: nyet on June 07, 2022, 04:06:12 PM This doesn't make much sense
Why are the imx trims going DOWN during underboost? Title: Re: not reaching desired boost Post by: aef on June 07, 2022, 10:01:13 PM Maybe its because i am near sensor limit? At least Ecu is thinking this although im running big sensor and 5120hack?
So it is not related to heat developing from first to fifth log or something, its more like a long term trim and connected to point in time after last flash? I reflashed the ecu yesterday before first log. ::) Title: Re: not reaching desired boost Post by: nyet on June 07, 2022, 10:04:15 PM Not sure, i've never seen that trim behavior.
Title: Re: not reaching desired boost Post by: nyet on June 07, 2022, 10:05:41 PM If I had to guess, there is a sign error somewhere.
Title: Re: not reaching desired boost Post by: spacey3 on June 08, 2022, 02:07:23 AM my LDEIAO, LDEIAP, LDEIAPS and LDEIAU is chanced a bit from stock could be related to 5120hack, i have to check my old revisions when i changed this and why LDEIAO from 40 to 20 LDEIAP from -20 to 1270 LDEIAPS from 50 to 20 LDEIAU from -60 to 1270 ::) LDIATA and STLDIA is stock. What do you want me to log? I have nothing like STDIA in my logger config(s) thx Not sure if this will help you at all, but I took a look at a 5120 file I've done for a sanity check. Each of the params above I divided by 2. LDEIOU 40 -> 20 LDEIAP -40 -> -20 LDEIAPS 60 -> 30 LDEIAU -40 -> -20 Though I'm not running the pre control method. Title: Re: not reaching desired boost Post by: aef on June 08, 2022, 02:23:20 AM just found a human error in LDRQ1ST 16x1
i only doubled the 1st value, not the whole map and i chanced LDEIAP and LDEIAU from some posts before -20 to -10 and -60 to -30 will log again edit: thx spacey3 for your hint Title: Re: not reaching desired boost Post by: nyet on June 08, 2022, 11:22:13 AM Definitely not a noob topic :) Moving to main tuning forum, as this could be helpful for others
Title: Re: not reaching desired boost Post by: aef on June 20, 2022, 01:39:53 PM Solved, thank you gentlemen
I am not sure which of the 3 maps was the problem, i didnt test them individually. All of the imx trims are within a small range now. attached first and fifth log |