[s-cars] Of MAF's and voltages

[Trevor Frank]

So I have been doing a bit of tuning with Mihnea's help and the aid of a
voltage remapper from Split Second.  I have gotten a fairly large, 4"
inlet 3.5" outlet hot plate monometer to work on my car very well. 



In doing so I have been monitoring MAF voltages unmolested and molested
by my voltage mapper.  I think that I have found some interesting
things, at least some things that I didn't realize, but maybe should
have.



The RS2 maf is appropriately sized to full scale on a basically stock
RS2, at 320 hp I basically see full voltage out of the maf.  This makes
sense because they want to use all the voltage to get the best
resolution.  So all of us running over 320hp you will see that the maf
voltage maxes out and past that the motronic in it's infinite wisdom
relies on other things I suspect to calculate load.



I suspect that this poor hot wire monometer that is being given all the
voltage it can and in Hap, MLP and old Edwins case starting at a very
low rpm, it is no surprise the old thing get's ripped out, although this
is not the case for these three people/cars anymore they have all moved
on in one way or another..



So moving on to a larger maf my thought was always to copy the RS2
voltage map and enjoy the benefits of a lower delta P across the maf,
and hopefully the intake track.  But my realization that I would be
running into full voltage at 3k or so meant that it would make more
sense and with Mihnea help to first correct the maps to RS2 then to
re-scale the maps to basically fatten up the maps so that I could lower
the voltage offset, or lower the voltage offset and put in bigger
injectors.  This way instead of full scale at 3-4k I am full scale at or
near full hp.   My though is this will lead to more accurate load
mapping and hopefully more average hp depending on conditions, also a
bit more safety, I think.



So I am wondering when you put a resistor in place to scale the maf, I
am speculating here so feel free to chime in, if you are in fact just
hindering the benefit's that it might have given to have "more accurate"
load calculations if you allowed it to represent it's true full scale to
the motronic, instead of trying to get it to mimic the RS2 to enable
tuning to be easier, at least this is how I think it is being done,
someone correct me.



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