LTrim - RPM & MAP Boundaries
LTrim - RPM & MAP Boundaries 
08-31-2006, 08:10 AM
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I usually leave that stock. I'm suspicious there are other parts of the tune we don't see or have access to that expect certain cells to do certain things. Once you start moving those cells around too much, things start to get screwy (at least they did on my '02).
08-31-2006, 10:30 AM
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I arranged RPM to segment into idle, low cruise, medium
acceleration and put the top line at the all-MAF cutover
of 4000Hz. 1000, 2000, 4000. My street cruising RPM is
usually below 2000 by part throttle shift settings and
highway is 2500. Want to not be straddling any of the
boundaries in general because it can get jerky if you
are popping from cell to cell. If you do a drive-cycle
scatter-plot of RPM and MAP you should be able to
see "bunching" in the primary driving "sweet spots"
and put the fence between the cows.
Similarly for MAP I put the bottom line just above idle
and the top line just above PE enable MAP (maybe I
should have made them coincident). 35, 45, 55. A
big cam car needs to untangle PE from idle, the
TPS threshold and RPM banding should do this but
a little "overspray" seems to be something I've
observed with PE adjustments pushing closed loop
trims. But then this could just be thermal history.
acceleration and put the top line at the all-MAF cutover
of 4000Hz. 1000, 2000, 4000. My street cruising RPM is
usually below 2000 by part throttle shift settings and
highway is 2500. Want to not be straddling any of the
boundaries in general because it can get jerky if you
are popping from cell to cell. If you do a drive-cycle
scatter-plot of RPM and MAP you should be able to
see "bunching" in the primary driving "sweet spots"
and put the fence between the cows.
Similarly for MAP I put the bottom line just above idle
and the top line just above PE enable MAP (maybe I
should have made them coincident). 35, 45, 55. A
big cam car needs to untangle PE from idle, the
TPS threshold and RPM banding should do this but
a little "overspray" seems to be something I've
observed with PE adjustments pushing closed loop
trims. But then this could just be thermal history.
