In the thread on Audi Sport it's explained (
https://www.audi-sport.net/xf/threads/1-8t-m3-8-3-tuning.355810/)
Old Bosch Mx is Cable throttle (Later they became MEx, Motronic with Egas)
M3.8 has no MAP sensor and only work on MAF were it convert MAF into Injection times and call it load in ms.
So M3.8 only knows how much air is going in, but the air going in is regulated by the thottle and the turbo.
-Without the turbo, you will only be able to achive around 5ms load.
-KFLDTV control the wastegate, If you request more load in KFLDS, you also need to adjust KFLDSTV to achive it, and if you go over LDSMXN it will cut boost and flag overboost.
-KFLDTV is a base map, it gets controlled by a PID. so if KFLDS don't meet requested, the PID will control the wastegate.
-KFLDP, KFLDI, DLDRN is the P, I, D maps.
-KFLDS has the factor 0,05 to show load in ms, if you change it to 10,24 you get an approximate MAP value. (I would still use load in ms.)
Ti = (Tl * [C,D,E...]) + Tv
Ti = Real injection time in ms
Tl = Load - Theoretical injection time in ms to achive lambda 1. (Comes from Tl = Q / (n * Ki))
Tv = TVUB - Injector latancy
C,D,E... = Correction maps
KFLF and KFLFAV are both correction maps, were 1,00 = 100% = no correction.
1,10 = 110% = +10% correction
0,90= 90% = -10% correction
"Tl = Load - Theoretical injection time in ms to achive lambda 1."
-So you request Tl in KFLDS.
"C,D,E... = Correction maps"
-Correction is applied in KFLF. So if we want to go under lambda 1 we need to add more fuel.
"Ti = Real injection time in ms"
-Ti is the result + TVUB.
So when you have your wideband and can log AFR, you know if you have to increase KFLF to get more fuel or decrease KFLF to get less fuel.
KFTLWS is the same as KFLDS, but KFTLWS is without MAF and is only for limp mode so it should not be tuned.
-"Tl = Q / (n * Ki)" without the MAF you are missing Q.
Hi, thank you ZpiXDK for having a look at the file. I've typed in the corrections you made, will upload it tomorrow.
I have a wideband and boost sensor already at home and waiting to be installed soon, although thank you for the advice.
My latest concerns with understanding this ecu are these two, I will be very appreciated if you can provide some input about how they work:
- How does KFLDS and LDSMXN interact to manage boost? Isn't KFLDTV supposed to control boost by N75 duty cycles? I still don't get how or why does ms/umdr (load) translate to boost.
- If KFLF is a correction map for the injection times, are KFLTLWS and KFLFAV the base maps for KFLF to correct from? In other words, the base maps for injection?
This ECU is a pain in the ass but I'll get it to work. Thank you very much in advance!