NefMoto

Technical => Diagnostics => Topic started by: Swakefield on October 15, 2020, 05:10:40 PM



Title: Requested/Actual Boost not matching LDRXN?
Post by: Swakefield on October 15, 2020, 05:10:40 PM
Hey guys, so after not having my car for 2 weeks while i had a Single mass flywheel and rs4 clutch kit installed (b6 a4 1.8t), i ran the car on a mostly stock tune while i broke in the clutch. After breaking it in I redid my tune back to ~17PSI peak like I had before. I flashed it and I figured all was good (moron). 

My boost gauge has always been somewhat innacurate so i didnt question when it read low. But i ran a log now that I have a Surface 3 for logging and tuning(laptop battery crapped itself), and Ive found out it is actually running low. Even after re-flashing, the logs show that the ECU is only requesting about ~14.5PSI? Even though in LDRXN thts not correct. And it requests 14.5PSI for most of the RPM range which doesnt follow what LDRXN is set too? This all worked fine before and ran very well at the 17.5 I had it set for. Can someone tell me whats wrong?

Not triggering EGT protection. My buddy who uses nefmoto as well who is better than me isnt completely sure either.

Log/Bin/Xdf Attached!

Thanks in advance! please tell me its something simple and im a moron.

File is a 518AK me7.5



Title: Re: Requested/Actual Boost not matching LDRXN?
Post by: nyet on October 15, 2020, 05:18:44 PM
This all worked fine before and ran very well at the 17.5 I had it set for.

You had what "set to 17.5"? LDRXN is not in PSI.

https://s4wiki.com/wiki/Tuning#Approximation

Log the rest of the req load variables.


Title: Re: Requested/Actual Boost not matching LDRXN?
Post by: Swakefield on October 15, 2020, 05:22:37 PM
You had what "set to 17.5"? LDRXN is not in PSI.

https://s4wiki.com/wiki/Tuning#Approximation

In my xdf I have a second LDRXN labeled "LDRXN PSI" at the end with a conversion in it that gets it relatively close. Every single time ive ever used it before, its always been accurate to within ~.5psi.

I missed a few variables in the logger, had to re-set it up on the new tablet. Ill change it and re-log.


Title: Re: Requested/Actual Boost not matching LDRXN?
Post by: nyet on October 15, 2020, 05:23:56 PM
In my xdf I have a second LDRXN labeled "LDRXN PSI" at the end with a conversion in it that gets it relatively close. Every single time ive ever used it before, its always been accurate to within ~.5psi

It isn't even close. There are a ton of other things that can affect it.

That approximation is a map I put in. I likely should not have, since people tend to think it means more than it is


Title: Re: Requested/Actual Boost not matching LDRXN?
Post by: Swakefield on October 16, 2020, 06:36:57 AM
Here is an updated log from this morning. I even tried an old bin from before I had my clutch done when it was hitting 17psi and it made no difference.


Title: Re: Requested/Actual Boost not matching LDRXN?
Post by: nyet on October 16, 2020, 12:14:57 PM
rl_sol is low due being capped by rl_max (LDRXN is rlmx). you'll need to log the other torque limits. Please reread the wiki.

https://s4wiki.com/wiki/Tuning#Boost_.28rlsol.29_intervention_via_rlmax
Quote
However, there are many things which cause rlmax to not follow rlmx

Please log them.


Title: Re: Re: Requested/Actual Boost not matching LDRXN?
Post by: Swakefield on October 23, 2020, 06:19:42 AM
rl_sol is low due being capped by rl_max (LDRXN is rlmx). you'll need to log the other torque limits. Please reread the wiki.

https://s4wiki.com/wiki/Tuning#Boost_.28rlsol.29_intervention_via_rlmax
Please log them.
Thank you for putting up with my lack of knowledge, you were right, i adjusted KFLDHBN(not at my computer so I cant confirm thats correct).  Now it follows KFLDHBN and I use ldrxn as a backup, set just higher than my highest curve in KFLDHBN (roughly).

Just to clarify, I know one axis is rpm, is the other coolant temp or IAT?( in reference to KFLDHBN.

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Title: Re: Re: Requested/Actual Boost not matching LDRXN?
Post by: nyet on October 23, 2020, 11:28:27 AM
Thank you for putting up with my lack of knowledge, you were right, i adjusted KFLDHBN(not at my computer so I cant confirm thats correct).  Now it follows KFLDHBN and I use ldrxn as a backup, set just higher than my highest curve in KFLDHBN (roughly).

Just to clarify, I know one axis is rpm, is the other coolant temp or IAT?( in reference to KFLDHBN.

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Please consult the FR. Considering this is a pressure ratio, see if you can guess which makes more sense, from a physics standpoint:


Title: Re: Re: Re: Requested/Actual Boost not matching LDRXN?
Post by: Swakefield on October 23, 2020, 12:21:42 PM
Please consult the FR. Considering this is a pressure ratio, see if you can guess which makes more sense, from a physics standpoint:
IAT makes more sense. My buddy said he thought it was coolant which didn't make sense to me.

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