correct KHFM-Calculation @ M3.83 /M3.8x?
eliotroyano:
Quote from: prj on March 27, 2014, 02:48:22 PM
This discussion does not matter in the slightest if you are going to be doing any actual tuning.
You are going to hit 12.75 load and you are f…d
After that you can downscale load using KHFM and scale fuelling back up via FGAT0. Of course you will have to re-do all the timing maps, cold start etc.
Thanks for your comment PRJ. As I understand from your comment, experience play a huge role in how to deal with old Motronic ECUs in a real world. But without that experience or detailed information, manage these ECUs gets hard, so only way to investigate about it, make some assumptions and with trial and error obtain some ideas/formulas about how to tune it as smart as possible.
In the case of this topic, in my humble opinion, I agree with MIL_On that KHFM could be something similar to KRKTE. Then our idea is try to define and modify KHFM in the same way that was done from the factory, letting us tweaking related ECU maps in a less empirical way.
MIL_on:
Quote from: prj on March 27, 2014, 02:48:22 PM
This discussion does not matter in the slightest if you are going to be doing any actual tuning.
You are going to hit 12.75 load and you are f…d
After that you can downscale load using KHFM and scale fuelling back up via FGAT0. Of course you will have to re-do all the timing maps, cold start etc.
touché, you're right ( as usual :P )
i only thought it could be easier to scale stuff by knowing the correct formula and being able to take the injectors into account in it.
but i also start to realize that theres no other way to do it other than tweak those few factors and constants till it fits.
overspeed:
Elio...As I said to you in MP...
Don´t try undertand M3.8 going down from ME7... it make no sense...
FGATO => fuel multiplier
Try looking at chanell 099 in VCDS
if you raise it => you get STFT going negative
if you low down it => you get STFT going positive
KHFM => is used to convert g/s in to load
It´s kind of logic that´s the most simple way to equation injector time to load in ms
eliotroyano:
Thanks a lot for the comment Overspeed ;D ;D ;D
prj:
When you hit 12.75 load you are going to have to rescale load anyway.
Otherwise it will just cap out and nothing will work.
Also make sure you never ever hit the MAF limit or really funny things will happen with N75 duty cycle as actual can not reach setpoint. And when I say funny, I mean molten engine stuff.
Basically to tune it for high outputs, scale down KHFM by a factor, so you never hit 12.75 load.
Then scale FGAT0 up by the same factor, so that they cancel each other out.
Then re-calibrate all the timing and fueling maps, as well as cold start maps and you're done.
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