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Title: Why are some stock ECU's so rich? (KFLBTS) Post by: s-company on January 25, 2011, 07:15:12 AM Hello!
For me it makes no sense why some stock KFLBTS maps are so rich, down to lambda 0,66. (a picture from S4 "D-box" is attached) If i make cars rich i set it maximum to 0,8, thats rich enough... imho Mybe someone can tell me the reason.. Best Regards Title: Re: Why are some stock ECU's so rich? (KFLBTS) Post by: Jason on January 25, 2011, 08:46:51 AM Sometimes it is to protect the catalysts by keeping the EGT's low. I think that OEM's don't want to rely on component protection being invoked all the time, so they try to richen areas where component protection would always be invoked.
But this is just a guess... Title: Re: Why are some stock ECU's so rich? (KFLBTS) Post by: nyet on January 25, 2011, 12:23:37 PM Hello! For me it makes no sense why some stock KFLBTS maps are so rich, down to lambda 0,66. (a picture from S4 "D-box" is attached) If i make cars rich i set it maximum to 0,8, thats rich enough... imho The enrichment is proportional to calc EGT vs TABGTBS. Unless your calc EGT gets significantly higher than TABGBTS, you'll never see your car run that rich. Go and log a stock ecu at WOT. Tell me what you see. http://s4wiki.com/wiki/Exhaust_gas_temperature#Audi_documentation Title: Re: Why are some stock ECU's so rich? (KFLBTS) Post by: s-company on January 26, 2011, 05:44:21 AM Hello nyet!
Yes, thats my next job with my ols300 and the Lambdatool, i will do some tests with kflbts and tabgbts to check egt and lambda. Anyway at the moment it makes no sense. The RS4 B5 for Example with 380HP is set to Lambda 0,9 at its richest point. tabgbts=800C° And the old S4 (551C box) with tabgbts=500C° is also set that rich like the D box.... 500C° is not much, so i guess this car often runs in kflbts. Whatever i will report my experience with emulator and Lambdatool here :-) Title: Re: Why are some stock ECU's so rich? (KFLBTS) Post by: Rick on January 26, 2011, 03:41:50 PM It will hit the KFLBTS value as soon as the EGT exceeds TABGBTS. It gets richer as the calculated EGT rises using FASTGBTS.
It won't however hit 0.6x as there is an absolute limit set in another map which isn't exceeded - it's around 0.7x. I set my KFLBTS to be the same as my LAMFA on boost - around 0.82 for max power. I then use the actual EGT sensors to richen the mixture if needed to protect. Rick Title: Re: Why are some stock ECU's so rich? (KFLBTS) Post by: nyet on January 26, 2011, 03:46:29 PM It will hit the KFLBTS value as soon as the EGT exceeds TABGBTS. It gets richer as the calculated EGT rises using FASTGBTS. It won't however hit 0.6x as there is an absolute limit set in another map which isn't exceeded - it's around 0.7x. Whoa. Thanks for the correction, Rick. Is FASTGBTS related to FSTABGM? What limit map are you referring to? Can you take a look at this http://s4wiki.com/wiki/Tuning#Desired_AFR and make suggestions? Thanks! Title: Re: Why are some stock ECU's so rich? (KFLBTS) Post by: Rick on January 27, 2011, 02:45:21 AM Sorry Nyet, I meant FSTABGM.
You multiply FSTABGM for a given calculated egt by KFLBTS to get the AFR. Obviously the Ignition correction maps come into play as well. The result cannot be richer or leaner than certain limits - i'll post the maps up later when I get home. Rick Title: Re: Why are some stock ECU's so rich? (KFLBTS) Post by: ArgDub on January 28, 2011, 05:39:42 AM @ Nyet
While reading this thread, I remember you asked me once what lambda is used when egt temperature exceeds TABGBTS, if LAMFA gets completely ignored when you hit TABGBTS and the fueling completely switches to KFLBTS, or if the ecu sets up "mixing" between the two as a transition. Well the mechanism very simple, in order to protect exhaust components the ecu always uses the smaller lambda. Hope that answers your question. Title: Re: Why are some stock ECU's so rich? (KFLBTS) Post by: nyet on January 28, 2011, 07:10:01 PM Sorry Nyet, I meant FSTABGM. You multiply FSTABGM for a given calculated egt by KFLBTS to get the AFR. Obviously the Ignition correction maps come into play as well. The result cannot be richer or leaner than certain limits Again, please help me refine http://s4wiki.com/wiki/Tuning#Desired_AFR. As far as i know, it is accurate... @ Nyet While reading this thread, I remember you asked me once what lambda is used when egt temperature exceeds TABGBTS, if LAMFA gets completely ignored when you hit TABGBTS and the fueling completely switches to KFLBTS, or if the ecu sets up "mixing" between the two as a transition. Well the mechanism very simple, in order to protect exhaust components the ecu always uses the smaller lambda. Hope that answers your question. Yes :) I tried to use that info to update s4wiki... hopefully what i have now is correct Title: Re: Why are some stock ECU's so rich? (KFLBTS) Post by: s-company on February 01, 2011, 05:23:09 PM Hello!
Another car makes me crazy, the opposite to the very rich maps above, look at this KFLBTS Map, also makes no sense, at least for me it makes no sense at the moment... Why its set to Lambda 1,500, thats strange... Is there a Correction map or something? Title: Re: Why are some stock ECU's so rich? (KFLBTS) Post by: Rick on February 07, 2011, 04:57:26 AM What does LAMFA look like, what is TABGBTS set to?
Rick Title: Re: Why are some stock ECU's so rich? (KFLBTS) Post by: s-company on February 07, 2011, 05:02:50 AM Hi!
TABGBTS is set to 500C Title: Re: Why are some stock ECU's so rich? (KFLBTS) Post by: Rick on February 07, 2011, 09:54:24 AM Is there there a FSTABGM map?
Title: Re: Why are some stock ECU's so rich? (KFLBTS) Post by: s-company on February 07, 2011, 11:12:07 AM Title: Re: Why are some stock ECU's so rich? (KFLBTS) Post by: ArgDub on February 07, 2011, 12:22:34 PM KFLBTS set to 1.5 or 0.6 lambda doesn't mean that you are going to end running that extreme values. As I said before, ecu uses the smaller lambda and max(LAMFA) is usualy set to 1, so setting KFLBTS higher than LAMFA, 1.5 eg, is the same as disable it.
Is strange FSTABGM all 1, isn't first value 0 |