In no way I had the flame-thrower pointed out at JD when I said that I thought that secondary fuel tweak dealt with idle fuel. I remember that I read from some post that it adjusted WOT fuel, but I tried it and never got any changes at WOT no matter how much I changed it. Then, I remember reading some info on motronic fuel trims and there i saw that there are 3 different types of fuel trims: offset, additive, and multiplicative.
the offset just adds fuel to the entire curve by a certain absolute number (say +3 arbitrary units to the entire curve. Then, at idle where fuel is 10 (just arbitrary numbers to give an example), the 3 added will have more effect than at WOT that the fuel is 1000. A fixed small number, affects the result by way more if you add it to a smaller number (less fuel at idle) than if you add it to a bigger number (more fuel up top). Therefore, this offset value or trim will almost only affect idle. I then assumed by elimination that this was the secondary, but have no proof or hard data to support this.
The linear term or additive term, adds a certain amount of fuel proportional to the already amount of fuel that there is. such as a linear funtion... so if you think of it as a x-y plot, and you have a fuel function f(x), then f(x)=mx+b, m would be the "additive" fuel trim or the primary in lemmi and the b will be the secondary.

Then there is a multiplicative or, as I think of it, a "derivative" term, which is dependant on the rate of change of the fuel such as a geometric term where the faster its changing, the more it adds (accel trim) and also the opposite, where the faster it decreases, the more it changes the fuel. Sorry about the run-ons... Hope this helps.
I have no proof of the secondary. I more or less concluded that it doesnt do much, if anything at all.
Regarding that specific AMS case, I dont know why you were not getting any more fuel as you added primary, since it should have been richer. That is a very strange fueling curve too... probably there is some flow limitation in the line. I would log inj pulse time and desired load/actual load to see if the ecu IS actually requesting more fuel and its just not getting there.

 

I had a tuner reseller tell me so. I just don't know. Have there been Vag logs showing an actual effect from lemmi tweaks on certain chips? Does it work with GIAC and APR and not with AMS?

It would be nice to have good information on what lemmi really does and whether it offsets, adds or multiplies through the adapdation channel. Revo will not tell. Nobody seems to know.

 

Wouldn't f(x) = mx+b be for offset, f(x) = (m+b)x for additive, f(x) = mbx for multiplicative ?

 

Yeah, their channel descriptions are pretty vague. What are the units of a "Tweak"?

 

and does revo keep it quiet cause they want to protect their ideas, or because they dont know?

 

I'm pretty sure, REVO knows. Wouldn't it make lemmi more sellable to people who could use the info?

 

Whoops, my bad. Let's say "more useful". :/

 

considering all the ME7 profiles that are out there. It assumes that the adaptation channels/data are in the same relative spaces on these ecus though and that could be hazzardous in some cases.

Overall a much appreciated tool for me vs having to figure out where to peek/poke to change adapatation settings with Vag_com or VAG_1551/2. You'd need many AoA/VWoA manuals and understanding of hex/block calculations/changes if Lemmi did not exist. The generalization there is probably for ease of use.

Remember VTune and its inception? Don't think it has changed much or maybe is gone because of APR's want to profile ecu types for tuning accuracy. I'm sure they know the ecus equally as well if not better but probably have the safety factor of tweaking at the top of their list vs broad accessability like Lemmi. Lemmi is free - use at your own risk - eliminates liability doesn't it?

 

thinking only about the changes that I want, since I dont know what it looks like initially.

 

Diego, I didn't take offense to your post at all. I understood that your intent was not malicious.