Custom STG2+ flashtune not reaching boost over 5500rpm

[PhoB]

Hello, i just did three or four revision of my custom tune. Spoted few issues, which i would be happy if anybody help me:

1. boost is start falling at 5500, looks like something starts to happen there, also STFT start to climb up +20%. Already tried to add 5% WGDC at this area, boost act the same(this log).

2. in file i set 195-190 load request, but target on log is only cca 180. Spoted torgue limit 4 active for a brief second

I feel like its some newbie issue, as i seen on many dynocharts power band starts to fall around 5500rpm (my issue?) and there is some limitation on load/boost reguest on pure flash tune - no MHD or any other thirdparty.

Car is 2007 335ix AT
-Custom hybrids(bigger both in+ex wheels), oem actuators + rattlefixed and preloaded half a pin diameter.
-Some bigger alloy FMIC
-OEM blow off valves, not cracked(vacuum tested)
-3in downpipes,no cats, 2.5in free flow exhausts
-FuelIT stg1 pump setup(255 in series)
-Alpina AT flash

here i a link, i cant post them here yet(reputation) so try it: datazap.me/u/phob/verze04?log=1&data=3-6-17-18-21-22-27

[PhoB]

I would be happy if you can point me for an answer, on how to set flat line boost at low rpm up to 3500. As Load req is flat and boost target is low, so i tried to rise Load at low rpm a bit, but to set to flat boost it must be huge load request and there is a limitation of it, so...

Also how can i cure STFT ? There is some scalar map in XDF, but seems not exist in OEM flash file - as repeat, i dont using MHD or any other, just OEM style file.

[PhoB]

Forgot to mention, car has drop in Pipercross filter, but im that doubt stock airbox can be so restrictiove to now allowing more than 8psi at 6800rpm. Did every STG1/2 tunes require intakes?

[Sticky]

here i a link, i cant post them here yet(reputation) so try it: datazap.me/u/phob/verze04?log=1&data=3-6-17-18-21-22-27

You can post links now: https://datazap.me/u/phob/verze04?lo...17-18-21-22-27

[PhoB]

thank you.

I just found, that my second issue it due non modified Load to torque limit table(s).

And i also ported top airbox part, to flow a bit better. Going to test it tommorow. Also going to check boost solenoid for leakage. As i think it will be mechanical issue than ECU.

[bradsm87]

Boost limit multiplier needs to be raised (I run 2.7 across the board on that one) and raise torque monitor ceiling way up out of the way.

[PhoB]

Was already set, according local xls spreadsheet and comparing several tuned files.

Here is my file prepared for a next test.I8A0Srom_05.zip

[CarAbuser]

What was the logic behind the "Max torque at clutch" change? I don't think the function of the table is fully understood so would revert that back to stock.

Also some questionable axis scaling on the WGDC adder axis' but I don't think that's causing the issue.

I do agree that the problem looks to be mechanical rather than the tune.

[PhoB]

Thanks for a reaction.
I just used setting of this map from some E30 base file, which contains a sense modification on other well know maps, so i trust it. I will try it set back.
WGDC adders is made as try to cure boost drop at high rpm, but as you can see, boost not following same path/progress as WGDC (mean constant rising WGDC with correct boost and it immediately starts to drop at certain RPM).

Here is a actual log with posted file, no change at all. At cca 180+ load there is some "silent" limiter. Ported or open airbox not change anything on boost drop.

https://datazap.me/u/phob/log-151196...22-24-26-28-30

[CarAbuser]

Given the trims go positive as boost starts to taper tells me that the ECU is trying to compensate for something mechanically but I may be wrong.

Positive trims means there's too much air or not enough fuel. Fuel pump pressure look fine so possibly either unmetered air getting into the engine or a problem with the O2 reading in the exhaust (fresh air getting in or sensor issue).

[RSL]

Boost mean is actual TMAP reading, boost is DME modeled boost, so something is going on between reality and what the DME thinks is going on.

https://datazap.me/u/phob/log-151196...-22&solo=18-19

I've seen this issue before, person said it resolved itself after not boosting for a while. It was also a 2007, so might be something specific to the MSD80/IA80S and maybe weather conditions?

From 2012:

I think I found a bug, feature, or very odd deliberate limit. I'm betting it's not the last one, but I digress. Fuel is staying where it should be when running the stage map I have been running.

Several of the internal calculations use MAF, a calculated value. Two different calculated MAF values are compared together to create a calculated pressure that, way down the road, hits the fuel calculations. In short one of the values was being clipped above 290ish g/s. I fixed the clipping and all is well now.

[PhoB]

Thank you RSL, i feel stupid about not know boost and boost mean difference, i logged it just now firstime. Actually, car is running smooth, the drop at 5500 was not notiecable in a car, now i know why
So my problem at 5500rm is the 290g/s limit, good point. Ecu start to use fuel for this amount of airflow, but engine is getting more, thats why im in positive climbing fuel trims.

And second issue is the reguest load limit, can i use 195? as i have 3000+3500rpm set 195 and then 190 (tried slightly bandaid low rpm boost target). I will try just 190.

[RSL]

Another 5 on load probably isn't going to make or break anything, but I'd be leery of increasing boost/load more with that issue. Trims are already high and not sure if you have it tuned like that, but AFR lean up a bit already, so keep a close eye on things.

[PhoB]

Make some progress, tried to copy some unknown changes from JB and EK stage 2 binaries, but doesnt have influence on anything.

I found, that my load request limit is probably due "torque output req nm" limited at 510nm , did not find solution for it. So i must extend Load to torque1/2/3 maps, now im at almost 1.2bar with just little over 510nm request.
Similar solution i did on my Maf limit issue, activated fuel scalar maps and add XX% at high load and rpm where its needed. Simply tuning on blind as on other cars with have maxedout maf

Log if anybody want a look, it was just test run, finetune needed.
https://datazap.me/u/phob/08scalar?l...23-28-29-30-31

[RSL]

Playing with fire. MAF calculation is not maxed out (there is no MAF to max out), calc will go well over 500g/s. It's a glitch or something in the tune/environment causing it to limit. That's holding down boost the DME seems, dropping your load and moving all parameters associated with it, but not actually limiting the actual boost. Actual load drops with the boost/MAF.

Torque request is capped at 510nm in the DME, torque output can be adjusted much higher, but you really need to stop trying to add until the MAF calculation gets resolved.

[CarAbuser]

Props to RSL for spotting that. I didn't check boost mean since I've never seen an issue like that!

Torque request is always maxed at 510. That isn't the source of the issues.

[PhoB]

CarAbuser: same on me, give RSL a rep I think i must fake DME to see lower than "real=OEMcalculated" torque to be able set load i want, so on more powerful car, DME than see ridiculous low torque. Therefore i think there must be a solution.

RSL: i know, but i didnt find any more info about it. I will pay for this info if anyone can quickly take a look on it. Now i setup is this way, have some experience from non bmw cars tuning, so will make it safe enought. I count with limited high rpm load also in timing and vanos.

In simply words, actual opensource info is enought for say DYI STG1 tune. Anything else need purchase OTS or custom map from commercial vendor - which have done hard work and solved the spoken "secret" limitation. If may i know it at beginning, never try to do my own custom tune from scratch and purchase some tune and than make a just finetune on it.

[RSL]

This seems like a pretty rare occurrence, but might consider working with an experienced tuner because of it.

[Tony@Codewerx]

The wgdc base is too low.

Revert wgdc base, adder and ceiling - scales and values to stock and do a datalog. From there let’s see if there is a hardware issue.

You are boosting from 5500 rpm and above with just 20+ % of wgdc base on stock turbos ?

There is only so much PID can do for you with that much of a difference to make up.

[RSL]

PID is actually pulling DC. Mean is at target, it's DME boost that's reading way low. In other words, he's really running boost at target, DME isn't following though.

https://datazap.me/u/phob/log-151196...olo=18&mark=39

[Tony@Codewerx]

Get the 3 wgdc tables sorted would a recommended start — he has a bunch of throttle closures as well which typically results in high boost means vs low boost numbers. ...