It seems to me the lamfa camp is saying use lamfa because you can have LAMKR fueling.
Why can't you have KR fuel when using BTS fueling? LAMFA = 1, and LAMKR < 1.

The root reason I created this thread was why fuel based on driver requested vs actual load.

Here's the same question from a different direction:

Current load input in LAMFA is mrfa_w (driver desired load). Would it be better if we changed that to rl_w (actual load) [and axis values to reflect >100]?

That way we can use BTS for what it is meant for. And for big turbo cars, we don't have to dump fuel in before car needs it.

I don't really want to re-tune my car just to point something out but I vaguely remember that my Lambda was not following driver's desired load when I had LAMFA table in use on my tune, I think it was followinf actual load...

It wouldn't be the first time FR was wrong about things.

I don't really remember as I was really testing BTS at that time. I had LAMFA set to lambda lower than 1 at very conservative 80 load and I wasn't seeing that when pedal was floored in low RPMs and desired load was definitely over 80. Only when engine started actually getting loaded then I started seeing Lambda falling down.

But I might be wrong. Please experiment and see when LAMFA is actually kicking in.

where's this even located on the mbox?

I have confirmed mrfa input into LAMFA both thru disassembly and testing with low TALFA (032HS/032LP/518AF boxes). It's hard to see the direct correlation between driver desire->lamfa->actual afr with a small frame turbo + TALFA + lowpassfilter at the end of LAMFAW. With the quick onset of actual load with a small turbo, it's hard to tell the difference between actual and requested load. Throw in a slight delay by the means of TALFA and lowpassfilter, and it makes it even harder.

The question is still out there.... Is there an advantage to driver desire fueling vs actual load fueling? Why did the engineers decide to go this route?
I under stand for NA cars. But with turbo cars where load above 100 depends on spool time of turbo, I don't see the merit. Again, this may be only an issue with slow spooling turbos.

Sorry for using torque and load interchangeably when I shouldn't. But I think you get the gist.

I'm not trying to say, I'm trying to ask: Is 'torque% request' based fueling better than actual load fueling?


Seems you are saying you use LAMFKR+LAMFA as your base fueling where as I bring up using BTS for base fueling. Seems you've done this in part because LAMFA by itself was not perfect for base fueling. This supports my concern that LAMFA alone is not perfect. We differ how we compensate for this I understand.

Why is LAMFA not perfect? I don't know how many more times I'll have to ask this question.

Another reason I like BTS over LAMFA and/or LAMKR: map resolution.

LAMFA and LMAKR are 8bit maps with only 6 load/torque axis nodes. Look at BTS. yummy. I'm considering not only changing input for LAMFA from mrfa to rl, but also changing/relocating map itself to mirror BTS map structure and hex lookup sequence. In other word replace LAMFA lookup code with a copy of BTS lookup code.

phila_dot, what turbo are you running? Stock? Why do yu feel you need fueling BEFORE actual load? Why does a car need fueling < 1 before any significant actual load? This is where my tuning knowledge lacks a lot. Does a turbo engine produce more torque @ 0psi with lambda < 1 than with lambda = 1? I have a feeling it does which explains my obvious confusion.

anybody on 91/92 octane needs to run stock timing during fuel and maf calibration phases as a strict consequence of this.
this has been my experience in oregon even with low IAT's [due to cool wet conditions].

Just a reminder since some might have missed a subtle point I made in my post about KR fueling.

The reason why KR fueling is superior to LAMFA junk is that you can re-define KFLAMKRL table so that first row is for "0.00" knock. When you do that, the LAMBDA will be calculated for normal operating condition without knock.

Since lowest LAMBDA prevails, KR fueling then becomes your fueling path.

Many are belly aching about LAMFA being in-appropriate in that it uses driver's indicated load instead of actual engine load, some want to alter assembly code and generally look for stuff they can easily get by making that slight alteration to KFLAMKRL table!

KFLAMKRL uses real load. Just stick your desired AFR/Lambda into "0.00" knock row/your load threshold column and voila. With "0.00" row there is no "by the time KR correction kicks in, its too late" situation since it is real time (like BTS for a given EGT temp) and instantaneous fueling.

You then use rest of table to react to knock/CFs. I still use BTS for temp over 900c to seriously douse the engine even if knock is not large enough for KR to already accomplish that by then.

There is also ATR system which acts on physical EGT sensors readouts, as a last resort.

I think we all understand LAMKR. I believe elray's point was about map resolution and nyet was referring to actual knock regulation dwkrz etc.

Why set BTS so high basically duplicating ATR?