HPTuners - MAP to KPA Vac?
07-09-2004, 09:57 AM
#1
HPTuners - MAP to KPA Vac? Hi all, Im trying to get my LTFT's all straightened out with a stock MAF before I move back to my ported MAF. All my LTFT's are in line (-2 to -4) except for my idle and decel FTCs which have a LTFT of +6. I know that most people dont bother tuning for the idle or decel cell, however Id like to get those inline as well so that when I switch over to the ported MAF, I can accurately scale the MAF frequency over the whole range, not just the usable cells. After logging, I know that the Idle and decel cells (FTCs 19 and 21) have an average MAP of 4.2 and 2.7 respectively. What do these MAPs translate to in terms of KPA Vac., as used in the IFR table?
This poses yet another problem, should I get these MAPs richened up to get the LTFT's down, what happens about overlapping MAP FTCs? For instance, If i richen everything from 2.7 - 4.2 MAP to richen up idle and decel, that will over richen cells 0 and 1, with 3.5 and 3.4 MAPs. I dont want idle and decel FTCs stepping on real FTCs toes. Perhaps there's another way to tune for this? Perhaps MAF scaling is the only way, even though I wanted to keep from scaling the MAF freq. till I get my ported MAF back on there.
Any input?
This poses yet another problem, should I get these MAPs richened up to get the LTFT's down, what happens about overlapping MAP FTCs? For instance, If i richen everything from 2.7 - 4.2 MAP to richen up idle and decel, that will over richen cells 0 and 1, with 3.5 and 3.4 MAPs. I dont want idle and decel FTCs stepping on real FTCs toes. Perhaps there's another way to tune for this? Perhaps MAF scaling is the only way, even though I wanted to keep from scaling the MAF freq. till I get my ported MAF back on there.
Any input?
07-09-2004, 10:52 AM
#2
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PSI Vac = BARO-MAP
kPa Vac = PSI Vac * 6.89
The VCM_Editor>Tools>Unit_Conversion menu will
help you out with this kind of stuff.
Idle and decel I think are stronly affected by the
VE table and the speed-density calculations, as
the MAF is known-inaccurate at low flow these
cells use the SD as part of fuel shot, not just a
"sanity checker". Bunch of people messing with
the VE trying to get it right, no real clear "recipe"
I've seen (too variable w/ mods, which is the
whole reason the MAF is the main metering for
as much of the operating range, as it will give
sane data over).
kPa Vac = PSI Vac * 6.89
The VCM_Editor>Tools>Unit_Conversion menu will
help you out with this kind of stuff.
Idle and decel I think are stronly affected by the
VE table and the speed-density calculations, as
the MAF is known-inaccurate at low flow these
cells use the SD as part of fuel shot, not just a
"sanity checker". Bunch of people messing with
the VE trying to get it right, no real clear "recipe"
I've seen (too variable w/ mods, which is the
whole reason the MAF is the main metering for
as much of the operating range, as it will give
sane data over).
